Search | arXiv e-print repository

<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"/> <meta name="viewport" content="width=device-width, initial-scale=1"/>  <link rel="apple-touch-icon" sizes="180x180" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/apple-touch-icon.png"> <link rel="icon" type="image/png" sizes="32x32" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/favicon-16x16.png"> <link rel="manifest" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/site.webmanifest"> <link rel="mask-icon" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/safari-pinned-tab.svg" color="#b31b1b"> <link rel="shortcut icon" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/favicon.ico"> <meta name="msapplication-TileColor" content="#b31b1b"> <meta name="msapplication-config" content="images/icons/browserconfig.xml"> <meta name="theme-color" content="#b31b1b">  <title>Search | arXiv e-print repository</title> <script defer src="https://static.arxiv.org/static/base/1.0.0a5/fontawesome-free-5.11.2-web/js/all.js"></script> <link rel="stylesheet" href="https://static.arxiv.org/static/base/1.0.0a5/css/arxivstyle.css" /> <script type="text/x-mathjax-config"> MathJax.Hub.Config({ messageStyle: "none", extensions: ["tex2jax.js"], jax: ["input/TeX", "output/HTML-CSS"], tex2jax: { inlineMath: [ ['$','$'], ["\$","\$"] ], displayMath: [ ['$$','$$'], ["\\[","\\]"] ], processEscapes: true, ignoreClass: '.*', processClass: 'mathjax.*' }, TeX: { extensions: ["AMSmath.js", "AMSsymbols.js", "noErrors.js"], noErrors: { inlineDelimiters: ["$","$"], multiLine: false, style: { "font-size": "normal", "border": "" } } }, "HTML-CSS": { availableFonts: ["TeX"] } }); </script> <script src='//static.arxiv.org/MathJax-2.7.3/MathJax.js'></script> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/notification.js"></script> <link rel="stylesheet" href="https://static.arxiv.org/static/search/0.5.6/css/bulma-tooltip.min.css" /> <link rel="stylesheet" href="https://static.arxiv.org/static/search/0.5.6/css/search.css" /> <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha256-k2WSCIexGzOj3Euiig+TlR8gA0EmPjuc79OEeY5L45g=" crossorigin="anonymous"></script> <script src="https://static.arxiv.org/static/search/0.5.6/js/fieldset.js"></script> <style> radio#cf-customfield_11400 { display: none; } </style> </head> <body> <header><a href="#main-container" class="is-sr-only">Skip to main content</a>  <div class="attribution level is-marginless" role="banner"> <div class="level-left"> <a class="level-item" href="https://cornell.edu/"><img src="https://static.arxiv.org/static/base/1.0.0a5/images/cornell-reduced-white-SMALL.svg" alt="Cornell University" width="200" aria-label="logo" /></a> </div> <div class="level-right is-marginless"><p class="sponsors level-item is-marginless"><span id="support-ack-url">We gratefully acknowledge support from<br /> the Simons Foundation, <a href="https://info.arxiv.org/about/ourmembers.html">member institutions</a>, and all contributors. <a href="https://info.arxiv.org/about/donate.html">Donate</a></span></p></div> </div>  <div class="identity level is-marginless"> <div class="level-left"> <div class="level-item"> <a class="arxiv" href="https://arxiv.org/" aria-label="arxiv-logo"> <img src="https://static.arxiv.org/static/base/1.0.0a5/images/arxiv-logo-one-color-white.svg" aria-label="logo" alt="arxiv logo" width="85" style="width:85px;"/> </a> </div> </div> <div class="search-block level-right"> <form class="level-item mini-search" method="GET" action="https://arxiv.org/search"> <div class="field has-addons"> <div class="control"> <input class="input is-small" type="text" name="query" placeholder="Search..." aria-label="Search term or terms" /> <p class="help"><a href="https://info.arxiv.org/help">Help</a> | <a href="https://arxiv.org/search/advanced">Advanced Search</a></p> </div> <div class="control"> <div class="select is-small"> <select name="searchtype" aria-label="Field to search"> <option value="all" selected="selected">All fields</option> <option value="title">Title</option> <option value="author">Author</option> <option value="abstract">Abstract</option> <option value="comments">Comments</option> <option value="journal_ref">Journal reference</option> <option value="acm_class">ACM classification</option> <option value="msc_class">MSC classification</option> <option value="report_num">Report number</option> <option value="paper_id">arXiv identifier</option> <option value="doi">DOI</option> <option value="orcid">ORCID</option> <option value="author_id">arXiv author ID</option> <option value="help">Help pages</option> <option value="full_text">Full text</option> </select> </div> </div> <input type="hidden" name="source" value="header"> <button class="button is-small is-cul-darker">Search</button> </div> </form> </div> </div>  <div class="container"> <div class="user-tools is-size-7 has-text-right has-text-weight-bold" role="navigation" aria-label="User menu"> <a href="https://arxiv.org/login">Login</a> </div> </div> </header> <main class="container" id="main-container"> <div class="level is-marginless"> <div class="level-left"> <h1 class="title is-clearfix"> Showing 1–50 of 100 results for author: <span class="mathjax">Gillanders, G H</span> </h1> </div> <div class="level-right is-hidden-mobile">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> <div class="content"> <form method="GET" action="/search/astro-ph" aria-role="search"> Searching in archive <strong>astro-ph</strong>. <a href="/search/?searchtype=author&query=Gillanders%2C+G+H">Search in all archives.</a> <div class="field has-addons-tablet"> <div class="control is-expanded"> <label for="query" class="hidden-label">Search term or terms</label> <input class="input is-medium" id="query" name="query" placeholder="Search term..." type="text" value="Gillanders, G H"> </div> <div class="select control is-medium"> <label class="is-hidden" for="searchtype">Field</label> <select class="is-medium" id="searchtype" name="searchtype"><option value="all">All fields</option><option value="title">Title</option><option selected value="author">Author(s)</option><option value="abstract">Abstract</option><option value="comments">Comments</option><option value="journal_ref">Journal reference</option><option value="acm_class">ACM classification</option><option value="msc_class">MSC classification</option><option value="report_num">Report number</option><option value="paper_id">arXiv identifier</option><option value="doi">DOI</option><option value="orcid">ORCID</option><option value="license">License (URI)</option><option value="author_id">arXiv author ID</option><option value="help">Help pages</option><option value="full_text">Full text</option></select> </div> <div class="control"> <button class="button is-link is-medium">Search</button> </div> </div> <div class="field"> <div class="control is-size-7"> <label class="radio"> <input checked id="abstracts-0" name="abstracts" type="radio" value="show"> Show abstracts </label> <label class="radio"> <input id="abstracts-1" name="abstracts" type="radio" value="hide"> Hide abstracts </label> </div> </div> <div class="is-clearfix" style="height: 2.5em"> <div class="is-pulled-right"> <a href="/search/advanced?terms-0-term=Gillanders%2C+G+H&terms-0-field=author&size=50&order=-announced_date_first">Advanced Search</a> </div> </div> <input type="hidden" name="order" value="-announced_date_first"> <input type="hidden" name="size" value="50"> </form> <div class="level breathe-horizontal"> <div class="level-left"> <form method="GET" action="/search/"> <div style="display: none;"> <select id="searchtype" name="searchtype"><option value="all">All fields</option><option value="title">Title</option><option selected value="author">Author(s)</option><option value="abstract">Abstract</option><option value="comments">Comments</option><option value="journal_ref">Journal reference</option><option value="acm_class">ACM classification</option><option value="msc_class">MSC classification</option><option value="report_num">Report number</option><option value="paper_id">arXiv identifier</option><option value="doi">DOI</option><option value="orcid">ORCID</option><option value="license">License (URI)</option><option value="author_id">arXiv author ID</option><option value="help">Help pages</option><option value="full_text">Full text</option></select> <input id="query" name="query" type="text" value="Gillanders, G H"> <ul id="abstracts"><li><input checked id="abstracts-0" name="abstracts" type="radio" value="show"> <label for="abstracts-0">Show abstracts</label></li><li><input id="abstracts-1" name="abstracts" type="radio" value="hide"> <label for="abstracts-1">Hide abstracts</label></li></ul> </div> <div class="box field is-grouped is-grouped-multiline level-item"> <div class="control"> <span class="select is-small"> <select id="size" name="size"><option value="25">25</option><option selected value="50">50</option><option value="100">100</option><option value="200">200</option></select> </span> <label for="size">results per page</label>. </div> <div class="control"> <label for="order">Sort results by</label> <span class="select is-small"> <select id="order" name="order"><option selected value="-announced_date_first">Announcement date (newest first)</option><option value="announced_date_first">Announcement date (oldest first)</option><option value="-submitted_date">Submission date (newest first)</option><option value="submitted_date">Submission date (oldest first)</option><option value="">Relevance</option></select> </span> </div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Gillanders%2C+G+H&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Gillanders%2C+G+H&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Gillanders%2C+G+H&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Gillanders%2C+G+H&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.11894">arXiv:2109.11894</a> <span> [<a href="https://arxiv.org/pdf/2109.11894">pdf</a>, <a href="https://arxiv.org/format/2109.11894">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac29b7">10.3847/1538-4357/ac29b7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of the gamma-ray binary HESS J0632+057 with the H.E.S.S., MAGIC, and VERITAS telescopes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Adams%2C+C+B">C. B. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Capasso%2C+M">M. Capasso</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Farrell%2C+K+A">K. A. Farrell</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Foote%2C+G">G. Foote</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hassan%2C+T">T. Hassan</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hona%2C+B">B. Hona</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Jin%2C+W">W. Jin</a> , et al. (387 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2109.11894v1-abstract-short" style="display: inline;"> The results of gamma-ray observations of the binary system HESS J0632+057 collected during 450 hours over 15 years, between 2004 and 2019, are presented. Data taken with the atmospheric Cherenkov telescopes H.E.S.S., MAGIC, and VERITAS at energies above 350 GeV were used together with observations at X-ray energies obtained with Swift-XRT, Chandra, XMM-Newton, NuSTAR, and Suzaku. Some of these obs… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.11894v1-abstract-full').style.display = 'inline'; document.getElementById('2109.11894v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.11894v1-abstract-full" style="display: none;"> The results of gamma-ray observations of the binary system HESS J0632+057 collected during 450 hours over 15 years, between 2004 and 2019, are presented. Data taken with the atmospheric Cherenkov telescopes H.E.S.S., MAGIC, and VERITAS at energies above 350 GeV were used together with observations at X-ray energies obtained with Swift-XRT, Chandra, XMM-Newton, NuSTAR, and Suzaku. Some of these observations were accompanied by measurements of the H伪 emission line. A significant detection of the modulation of the VHE gamma-ray fluxes with a period of 316.7+-4.4 days is reported, consistent with the period of 317.3+-0.7 days obtained with a refined analysis of X-ray data. The analysis of data of four orbital cycles with dense observational coverage reveals short timescale variability, with flux-decay timescales of less than 20 days at very high energies. Flux variations observed over the time scale of several years indicate orbit-to-orbit variability. The analysis confirms the previously reported correlation of X-ray and gamma-ray emission from the system at very high significance, but can not find any correlation of optical H伪 parameters with X-ray or gamma-ray energy fluxes in simultaneous observations. The key finding is that the emission of HESS J0632+057 in the X-ray and gamma-ray energy bands is highly variable on different time scales. The ratio of gamma-ray to X-ray flux shows the equality or even dominance of the gamma-ray energy range. This wealth of new data is interpreted taking into account the insufficient knowledge of the ephemeris of the system, and discussed in the context of results reported on other gamma-ray binary systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.11894v1-abstract-full').style.display = 'none'; document.getElementById('2109.11894v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication by The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.05119">arXiv:2109.05119</a> <span>  </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> VERITAS contributions to the 37th International Cosmic Ray Conference </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Adams%2C+C+B">C. B. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Capasso%2C+M">M. Capasso</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Farrell%2C+K+A">K. A. Farrell</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Foote%2C+G+M">G. M. Foote</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hona%2C+B">B. Hona</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Jin%2C+W">W. Jin</a> , et al. (36 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2109.05119v1-abstract-short" style="display: inline;"> Compilation of papers presented by the VERITAS Collaboration at the 37th International Cosmic Ray Conference (ICRC), held July 12 through July 23, 2021 (online) in Berlin, Germany. </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.05119v1-abstract-full" style="display: none;"> Compilation of papers presented by the VERITAS Collaboration at the 37th International Cosmic Ray Conference (ICRC), held July 12 through July 23, 2021 (online) in Berlin, Germany. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.05119v1-abstract-full').style.display = 'none'; document.getElementById('2109.05119v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">html page. 2021 ICRC, Berlin, Germany</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.12735">arXiv:2104.12735</a> <span> [<a href="https://arxiv.org/pdf/2104.12735">pdf</a>, <a href="https://arxiv.org/format/2104.12735">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/abf926">10.3847/1538-4357/abf926 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> VERITAS Observations of the Galactic Center Region at Multi-TeV Gamma-Ray Energies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Adams%2C+C+B">C. B. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Capasso%2C+M">M. Capasso</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Jin%2C+W">W. Jin</a>, <a href="/search/astro-ph?searchtype=author&query=Kaaret%2C+P">P. Kaaret</a> , et al. (34 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2104.12735v1-abstract-short" style="display: inline;"> The Galactic Center (GC) region hosts a variety of powerful astronomical sources and rare astrophysical processes that emit a large flux of non-thermal radiation. The inner 375 pc x 600 pc region, called the Central Molecular Zone, is home to the supermassive black hole Sagittarius A*, massive cloud complexes, and particle accelerators such as supernova remnants. We present the results of our impr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.12735v1-abstract-full').style.display = 'inline'; document.getElementById('2104.12735v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.12735v1-abstract-full" style="display: none;"> The Galactic Center (GC) region hosts a variety of powerful astronomical sources and rare astrophysical processes that emit a large flux of non-thermal radiation. The inner 375 pc x 600 pc region, called the Central Molecular Zone, is home to the supermassive black hole Sagittarius A*, massive cloud complexes, and particle accelerators such as supernova remnants. We present the results of our improved analysis of the very-high-energy (VHE) gamma-ray emission above 2 TeV from the GC using 125 hours of data taken with the VERITAS imaging-atmospheric Cherenkov telescope between 2010 and 2018. The central source VER J1745-290, consistent with the position of Sagittarius A*, is detected at a significance of 38 standard deviations above the background level $(38蟽)$, and we report its spectrum and light curve. Its differential spectrum is consistent with a power law with exponential cutoff, with a spectral index of $2.12^{+0.22}_{-0.17}$, a flux normalization at 5.3 TeV of $1.27^{+0.22}_{-0.23}\times 10^{-13}$ TeV-1 cm-2 s-1, and cutoff energy of $10.0^{+4.0}_{-2.0}$ TeV. We also present results on the diffuse emission near the GC, obtained by combining data from multiple regions along the GC ridge which yield a cumulative significance of $9.5蟽$. The diffuse GC ridge spectrum is best fit by a power law with a hard index of 2.19 $\pm$ 0.20, showing no evidence of a cutoff up to 40 TeV. This strengthens the evidence for a potential accelerator of PeV cosmic rays being present in the GC. We also provide spectra of the other sources in our field of view with significant detections, composite supernova remnant G0.9+0.1 and HESS J1746-285. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.12735v1-abstract-full').style.display = 'none'; document.getElementById('2104.12735v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 8 figures, Accepted for publication in Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2005.03110">arXiv:2005.03110</a> <span> [<a href="https://arxiv.org/pdf/2005.03110">pdf</a>, <a href="https://arxiv.org/format/2005.03110">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab910e">10.3847/1538-4357/ab910e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> VERITAS Discovery of VHE Emission from the Radio Galaxy 3C 264: A Multi-Wavelength Study </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Carini%2C+M+T">M. T. Carini</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Fortin%2C+P">P. Fortin</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Georganopoulos%2C+M">M. Georganopoulos</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hassan%2C+T">T. Hassan</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a> , et al. (45 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2005.03110v1-abstract-short" style="display: inline;"> The radio source 3C 264, hosted by the giant elliptical galaxy NGC 3862, was observed with VERITAS between February 2017 and May 2019. These deep observations resulted in the discovery of very-high-energy (VHE; E $>100$ GeV) $纬$-ray emission from this active galaxy. An analysis of $\sim$57 hours of quality-selected live time yields a detection at the position of the source, corresponding to a stat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.03110v1-abstract-full').style.display = 'inline'; document.getElementById('2005.03110v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2005.03110v1-abstract-full" style="display: none;"> The radio source 3C 264, hosted by the giant elliptical galaxy NGC 3862, was observed with VERITAS between February 2017 and May 2019. These deep observations resulted in the discovery of very-high-energy (VHE; E $>100$ GeV) $纬$-ray emission from this active galaxy. An analysis of $\sim$57 hours of quality-selected live time yields a detection at the position of the source, corresponding to a statistical significance of 7.8 standard deviations above background. The observed VHE flux is variable on monthly time scales, with an elevated flux seen in 2018 observations. The VHE emission during this elevated state is well-characterized by a power-law spectrum with a photon index $螕= 2.20 \pm 0.27$ and flux F($>315$ GeV) = ($7.6\pm 1.2_{\mathrm stat} \pm 2.3_{\mathrm syst})\times 10^{-13}$ cm$^{-2}$ s$^{-1}$, or approximately 0.7% of the Crab Nebula flux above the same threshold. 3C 264 ($z = 0.0217$) is the most distant radio galaxy detected at VHE, and the elevated state is thought to be similar to that of the famously outbursting jet in M 87. Consequently, extensive contemporaneous multi-wavelength data were acquired in 2018 at the time of the VHE high state. An analysis of these data, including VLBA, VLA, HST, Chandra and Swift observations in addition to the VERITAS data, is presented, along with a discussion of the resulting spectral energy distribution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.03110v1-abstract-full').style.display = 'none'; document.getElementById('2005.03110v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 11 figures, Accepted for publication in Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2003.13615">arXiv:2003.13615</a> <span> [<a href="https://arxiv.org/pdf/2003.13615">pdf</a>, <a href="https://arxiv.org/format/2003.13615">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab8310">10.3847/1538-4357/ab8310 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evidence for proton acceleration up to TeV energies based on VERITAS and Fermi-LAT observations of the Cas A SNR </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Das%2C+S">S. Das</a>, <a href="/search/astro-ph?searchtype=author&query=Dwarkadas%2C+V+V">V. V. Dwarkadas</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hassan%2C+T">T. Hassan</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a> , et al. (38 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2003.13615v1-abstract-short" style="display: inline;"> We present a study of $纬$-ray emission from the core-collapse supernova remnant Cas~A in the energy range from 0.1GeV to 10TeV. We used 65 hours of VERITAS data to cover 200 GeV - 10 TeV, and 10.8 years of \textit{Fermi}-LAT data to cover 0.1-500 GeV. The spectral analysis of \textit{Fermi}-LAT data shows a significant spectral curvature around $1.3 \pm 0.4_{stat}$ GeV that is consistent with the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.13615v1-abstract-full').style.display = 'inline'; document.getElementById('2003.13615v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2003.13615v1-abstract-full" style="display: none;"> We present a study of $纬$-ray emission from the core-collapse supernova remnant Cas~A in the energy range from 0.1GeV to 10TeV. We used 65 hours of VERITAS data to cover 200 GeV - 10 TeV, and 10.8 years of \textit{Fermi}-LAT data to cover 0.1-500 GeV. The spectral analysis of \textit{Fermi}-LAT data shows a significant spectral curvature around $1.3 \pm 0.4_{stat}$ GeV that is consistent with the expected spectrum from pion decay. Above this energy, the joint spectrum from \textit{Fermi}-LAT and VERITAS deviates significantly from a simple power-law, and is best described by a power-law with spectral index of $2.17\pm 0.02_{stat}$ with a cut-off energy of $2.3 \pm 0.5_{stat}$ TeV. These results, along with radio, X-ray and $纬$-ray data, are interpreted in the context of leptonic and hadronic models. Assuming a one-zone model, we exclude a purely leptonic scenario and conclude that proton acceleration up to at least 6 TeV is required to explain the observed $纬$-ray spectrum. From modeling of the entire multi-wavelength spectrum, a minimum magnetic field inside the remnant of $B_{\mathrm{min}}\approx150\,\mathrm{渭G}$ is deduced. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.13615v1-abstract-full').style.display = 'none'; document.getElementById('2003.13615v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 March, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">33 pages, 9 Figures, 6 Tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2002.04119">arXiv:2002.04119</a> <span> [<a href="https://arxiv.org/pdf/2002.04119">pdf</a>, <a href="https://arxiv.org/format/2002.04119">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab765d">10.3847/1538-4357/ab765d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A decade of multi-wavelength observations of the TeV blazar 1ES 1215+303: Extreme shift of the synchrotron peak frequency and long-term optical-gamma-ray flux increase </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Valverde%2C+J">Janeth Valverde</a>, <a href="/search/astro-ph?searchtype=author&query=Horan%2C+D">Deirdre Horan</a>, <a href="/search/astro-ph?searchtype=author&query=Bernard%2C+D">Denis Bernard</a>, <a href="/search/astro-ph?searchtype=author&query=Fegan%2C+S">Stephen Fegan</a>, <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hassan%2C+T">T. Hassan</a> , et al. (64 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2002.04119v2-abstract-short" style="display: inline;"> Blazars are known for their variability on a wide range of timescales at all wavelengths. Most studies of TeV gamma-ray blazars focus on short timescales, especially during flares. With a decade of observations from the Fermi-LAT and VERITAS, we present an extensive study of the long-term multi-wavelength radio-to-gamma-ray flux-density variability, with the addition of a couple of short-time radi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.04119v2-abstract-full').style.display = 'inline'; document.getElementById('2002.04119v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.04119v2-abstract-full" style="display: none;"> Blazars are known for their variability on a wide range of timescales at all wavelengths. Most studies of TeV gamma-ray blazars focus on short timescales, especially during flares. With a decade of observations from the Fermi-LAT and VERITAS, we present an extensive study of the long-term multi-wavelength radio-to-gamma-ray flux-density variability, with the addition of a couple of short-time radio-structure and optical polarization observations of the blazar 1ES 1215+303 (z=0.130), with a focus on its gamma-ray emission from 100 MeV to 30 TeV. Multiple strong GeV gamma-ray flares, a long-term increase in the gamma-ray and optical flux baseline and a linear correlation between these two bands are observed over the ten-year period. Typical HBL behaviors are identified in the radio morphology and broadband spectrum of the source. Three stationary features in the innermost jet are resolved by VLBA at 43.1, 22.2, and 15.3 GHz. We employ a two-component synchrotron self-Compton model to describe different flux states of the source, including the epoch during which an extreme shift in energy of the synchrotron peak frequency from infrared to soft X-rays is observed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.04119v2-abstract-full').style.display = 'none'; document.getElementById('2002.04119v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in the Astrophysical Journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 891 (2020) 170 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2002.03567">arXiv:2002.03567</a> <span> [<a href="https://arxiv.org/pdf/2002.03567">pdf</a>, <a href="https://arxiv.org/format/2002.03567">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab6612">10.3847/1538-4357/ab6612 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Great Markarian 421 Flare of February 2010: Multiwavelength variability and correlation studies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Galante%2C+N">N. Galante</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hassan%2C+T">T. Hassan</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a> , et al. (234 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2002.03567v1-abstract-short" style="display: inline;"> We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during the month of February, 2010 when an extraordinary flare reaching a level of $\sim$27~Crab Units above 1~TeV was measured in very-high-energy (VHE) $纬$-rays with the VERITAS observatory. This is the highest flux state for Mrk 421 ever observed in VHE $纬$-rays. Data are analyzed from a co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.03567v1-abstract-full').style.display = 'inline'; document.getElementById('2002.03567v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.03567v1-abstract-full" style="display: none;"> We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during the month of February, 2010 when an extraordinary flare reaching a level of $\sim$27~Crab Units above 1~TeV was measured in very-high-energy (VHE) $纬$-rays with the VERITAS observatory. This is the highest flux state for Mrk 421 ever observed in VHE $纬$-rays. Data are analyzed from a coordinated campaign across multiple instruments including VHE $纬$-ray (VERITAS, MAGIC), high-energy (HE) $纬$-ray (Fermi-LAT), X-ray (Swift}, RXTE, MAXI), optical (including the GASP-WEBT collaboration and polarization data) and radio (Mets盲hovi, OVRO, UMRAO). Light curves are produced spanning multiple days before and after the peak of the VHE flare, including over several flare `decline' epochs. The main flare statistics allow 2-minute time bins to be constructed in both the VHE and optical bands enabling a cross-correlation analysis that shows evidence for an optical lag of $\sim$25-55 minutes, the first time-lagged correlation between these bands reported on such short timescales. Limits on the Doppler factor ($未\gtrsim 33$) and the size of the emission region ($ 未^{-1}R_B \lesssim 3.8\times 10^{13}\,\,\mbox{cm}$) are obtained from the fast variability observed by VERITAS during the main flare. Analysis of 10-minute-binned VHE and X-ray data over the decline epochs shows an extraordinary range of behavior in the flux-flux relationship: from linear to quadratic to lack of correlation to anti-correlation. Taken together, these detailed observations of an unprecedented flare seen in Mrk 421 are difficult to explain by the classic single-zone synchrotron self-Compton model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.03567v1-abstract-full').style.display = 'none'; document.getElementById('2002.03567v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">41 pages including 3 appendices, 13 figures; version accepted to Astrophysical Journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, Volume 890, Number 2 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1911.09434">arXiv:1911.09434</a> <span> [<a href="https://arxiv.org/pdf/1911.09434">pdf</a>, <a href="https://arxiv.org/format/1911.09434">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab59de">10.3847/1538-4357/ab59de <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Probing the Properties of the Pulsar Wind in the Gamma-Ray Binary HESS J0632+057 with NuSTAR and VERITAS Observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hassan%2C+T">T. Hassan</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Kaaret%2C+P">P. Kaaret</a> , et al. (38 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1911.09434v3-abstract-short" style="display: inline;"> HESS J0632+057 is a gamma-ray binary composed of a compact object orbiting a Be star with a period of about $315$ days. Extensive X-ray and TeV gamma-ray observations have revealed a peculiar light curve containing two peaks, separated by a dip. We present the results of simultaneous observations in hard X-rays with NuSTAR and in TeV gamma-rays with VERITAS, performed in November and December 2017… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.09434v3-abstract-full').style.display = 'inline'; document.getElementById('1911.09434v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.09434v3-abstract-full" style="display: none;"> HESS J0632+057 is a gamma-ray binary composed of a compact object orbiting a Be star with a period of about $315$ days. Extensive X-ray and TeV gamma-ray observations have revealed a peculiar light curve containing two peaks, separated by a dip. We present the results of simultaneous observations in hard X-rays with NuSTAR and in TeV gamma-rays with VERITAS, performed in November and December 2017. These observations correspond to the orbital phases $蠁\approx0.22$ and $0.3$, where the fluxes are rising towards the first light-curve peak. A significant variation of the spectral index from 1.77$\pm$0.05 to 1.56$\pm$0.05 is observed in the X-ray data. The multi-wavelength spectral energy distributions (SED) derived from the observations are interpreted in terms of a leptonic model, in which the compact object is assumed to be a pulsar and non-thermal radiation is emitted by high-energy electrons accelerated at the shock formed by the collision between the stellar and pulsar wind. The results of the SED fitting show that our data can be consistently described within this scenario, and allow us to estimate the magnetization of the pulsar wind at the location of the shock formation. The constraints on the pulsar-wind magnetization provided by our results are shown to be consistent with those obtained from other systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.09434v3-abstract-full').style.display = 'none'; document.getElementById('1911.09434v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 November, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1909.08114">arXiv:1909.08114</a> <span>  </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> VERITAS contributions to the 36th International Cosmic Ray Conference </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Das%2C+S">S. Das</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hassan%2C+T">T. Hassan</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a> , et al. (43 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1909.08114v2-abstract-short" style="display: inline;"> Compilation of papers presented by the VERITAS Collaboration at the 36th International Cosmic Ray Conference (ICRC), held July 24 through August 1, 2019 in Madison, Wisconsin. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.08114v2-abstract-full" style="display: none;"> Compilation of papers presented by the VERITAS Collaboration at the 36th International Cosmic Ray Conference (ICRC), held July 24 through August 1, 2019 in Madison, Wisconsin. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.08114v2-abstract-full').style.display = 'none'; document.getElementById('1909.08114v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">html page. 2019 ICRC, Madison, Wisconsin</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1904.06324">arXiv:1904.06324</a> <span> [<a href="https://arxiv.org/pdf/1904.06324">pdf</a>, <a href="https://arxiv.org/format/1904.06324">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41550-019-0741-z">10.1038/s41550-019-0741-z <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Direct measurement of stellar angular diameters by the VERITAS Cherenkov Telescopes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Giuri%2C+C">C. Giuri</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Halpern%2C+J">J. Halpern</a>, <a href="/search/astro-ph?searchtype=author&query=Hassan%2C+T">T. Hassan</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Joyce%2C+A+M">A. M. Joyce</a>, <a href="/search/astro-ph?searchtype=author&query=Kaaret%2C+P">P. Kaaret</a>, <a href="/search/astro-ph?searchtype=author&query=Kar%2C+P">P. Kar</a>, <a href="/search/astro-ph?searchtype=author&query=Kelley-Hoskins%2C+N">N. Kelley-Hoskins</a>, <a href="/search/astro-ph?searchtype=author&query=Kertzman%2C+M">M. Kertzman</a>, <a href="/search/astro-ph?searchtype=author&query=Kieda%2C+D">D. Kieda</a> , et al. (32 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1904.06324v1-abstract-short" style="display: inline;"> The angular size of a star is a critical factor in determining its basic properties. Direct measurement of stellar angular diameters is difficult: at interstellar distances stars are generally too small to resolve by any individual imaging telescope. This fundamental limitation can be overcome by studying the diffraction pattern in the shadow cast when an asteroid occults a star, but only when the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.06324v1-abstract-full').style.display = 'inline'; document.getElementById('1904.06324v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1904.06324v1-abstract-full" style="display: none;"> The angular size of a star is a critical factor in determining its basic properties. Direct measurement of stellar angular diameters is difficult: at interstellar distances stars are generally too small to resolve by any individual imaging telescope. This fundamental limitation can be overcome by studying the diffraction pattern in the shadow cast when an asteroid occults a star, but only when the photometric uncertainty is smaller than the noise added by atmospheric scintillation. Atmospheric Cherenkov telescopes used for particle astrophysics observations have not generally been exploited for optical astronomy due to the modest optical quality of the mirror surface. However, their large mirror area makes them well suited for such high-time-resolution precision photometry measurements. Here we report two occultations of stars observed by the VERITAS Cherenkov telescopes with millisecond sampling, from which we are able to provide a direct measurement of the occulted stars' angular diameter at the $\leq0.1$ milliarcsecond scale. This is a resolution never achieved before with optical measurements and represents an order of magnitude improvement over the equivalent lunar occultation method. We compare the resulting stellar radius with empirically derived estimates from temperature and brightness measurements, confirming the latter can be biased for stars with ambiguous stellar classifications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.06324v1-abstract-full').style.display = 'none'; document.getElementById('1904.06324v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 April, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Nature Astronomy</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1810.05271">arXiv:1810.05271</a> <span> [<a href="https://arxiv.org/pdf/1810.05271">pdf</a>, <a href="https://arxiv.org/format/1810.05271">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/aae70e">10.3847/2041-8213/aae70e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Periastron Observations of TeV Gamma-Ray Emission from a Binary System with a 50-year Period </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+VERITAS+Collaboration"> The VERITAS Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gent%2C+A">A. Gent</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hassan%2C+T">T. Hassan</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Kaaret%2C+P">P. Kaaret</a>, <a href="/search/astro-ph?searchtype=author&query=Kar%2C+P">P. Kar</a>, <a href="/search/astro-ph?searchtype=author&query=Kertzman%2C+M">M. Kertzman</a>, <a href="/search/astro-ph?searchtype=author&query=Kieda%2C+D">D. Kieda</a> , et al. (191 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1810.05271v1-abstract-short" style="display: inline;"> We report on observations of the pulsar / Be star binary system PSR J2032+4127 / MT91 213 in the energy range between 100 GeV and 20 TeV with the VERITAS and MAGIC imaging atmospheric Cherenkov telescope arrays. The binary orbit has a period of approximately 50 years, with the most recent periastron occurring on 2017 November 13. Our observations span from 18 months prior to periastron to one mont… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.05271v1-abstract-full').style.display = 'inline'; document.getElementById('1810.05271v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1810.05271v1-abstract-full" style="display: none;"> We report on observations of the pulsar / Be star binary system PSR J2032+4127 / MT91 213 in the energy range between 100 GeV and 20 TeV with the VERITAS and MAGIC imaging atmospheric Cherenkov telescope arrays. The binary orbit has a period of approximately 50 years, with the most recent periastron occurring on 2017 November 13. Our observations span from 18 months prior to periastron to one month after. A new, point-like, gamma-ray source is detected, coincident with the location of PSR J2032+4127 / MT91 213. The gamma-ray light curve and spectrum are well-characterized over the periastron passage. The flux is variable over at least an order of magnitude, peaking at periastron, thus providing a firm association of the TeV source with the pulsar / Be star system. Observations prior to periastron show a cutoff in the spectrum at an energy around 0.5 TeV. This result adds a new member to the small population of known TeV binaries, and it identifies only the second source of this class in which the nature and properties of the compact object are firmly established. We compare the gamma-ray results with the light curve measured with the X-ray Telescope (XRT) on board the Neil Gehrels \textit{Swift} Observatory and with the predictions of recent theoretical models of the system. We conclude that significant revision of the models is required to explain the details of the emission we have observed, and we discuss the relationship between the binary system and the overlapping steady extended source, TeV J2032+4130. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.05271v1-abstract-full').style.display = 'none'; document.getElementById('1810.05271v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 3 figures, 1 table. Accepted for publication in ApJL</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal Letters, 867:L19 (8pp), 2018 November 1 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1808.04300">arXiv:1808.04300</a> <span> [<a href="https://arxiv.org/pdf/1808.04300">pdf</a>, <a href="https://arxiv.org/ps/1808.04300">ps</a>, <a href="https://arxiv.org/format/1808.04300">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201833704">10.1051/0004-6361/201833704 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The extreme HBL behaviour of Markarian 501 during 2012 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ahnen%2C+M+L">M. L. Ahnen</a>, <a href="/search/astro-ph?searchtype=author&query=Ansoldi%2C+S">S. Ansoldi</a>, <a href="/search/astro-ph?searchtype=author&query=Antonelli%2C+L+A">L. A. Antonelli</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Babi%C4%87%2C+A">A. Babi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Banerjee%2C+B">B. Banerjee</a>, <a href="/search/astro-ph?searchtype=author&query=Bangale%2C+P">P. Bangale</a>, <a href="/search/astro-ph?searchtype=author&query=de+Almeida%2C+U+B">U. Barres de Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=Barrio%2C+J+A">J. A. Barrio</a>, <a href="/search/astro-ph?searchtype=author&query=Gonz%C3%A1lez%2C+J+B">J. Becerra Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Bednarek%2C+W">W. Bednarek</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Blanch%2C+O">O. Blanch</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">G. Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Carosi%2C+R">R. Carosi</a>, <a href="/search/astro-ph?searchtype=author&query=Carosi%2C+A">A. Carosi</a>, <a href="/search/astro-ph?searchtype=author&query=Chatterjee%2C+A">A. Chatterjee</a>, <a href="/search/astro-ph?searchtype=author&query=Colak%2C+S+M">S. M. Colak</a>, <a href="/search/astro-ph?searchtype=author&query=Colin%2C+P">P. Colin</a>, <a href="/search/astro-ph?searchtype=author&query=Colombo%2C+E">E. Colombo</a>, <a href="/search/astro-ph?searchtype=author&query=Contreras%2C+J+L">J. L. Contreras</a>, <a href="/search/astro-ph?searchtype=author&query=Cortina%2C+J">J. Cortina</a>, <a href="/search/astro-ph?searchtype=author&query=Covino%2C+S">S. Covino</a> , et al. (254 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1808.04300v2-abstract-short" style="display: inline;"> A multiwavelength campaign was organized to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on board the Swift and Fermi spacecraft, and the telescopes operated by the GASP-WEBT collaboration. Mrk 501 showed a very high energy (VHE) gamma-ray flux above 0… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.04300v2-abstract-full').style.display = 'inline'; document.getElementById('1808.04300v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.04300v2-abstract-full" style="display: none;"> A multiwavelength campaign was organized to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on board the Swift and Fermi spacecraft, and the telescopes operated by the GASP-WEBT collaboration. Mrk 501 showed a very high energy (VHE) gamma-ray flux above 0.2 TeV of $\sim$0.5 times the Crab Nebula flux (CU) for most of the campaign. The highest activity occurred on 2012 June 9, when the VHE flux was $\sim$3 CU, and the peak of the high-energy spectral component was found to be at $\sim$2 TeV. This study reports very hard X-ray spectra, and the hardest VHE spectra measured to date for Mrk 501. The fractional variability was found to increase with energy, with the highest variability occurring at VHE, and a significant correlation between the X-ray and VHE bands. The unprecedentedly hard X-ray and VHE spectra measured imply that their low- and high-energy components peaked above 5 keV and 0.5 TeV, respectively, during a large fraction of the observing campaign, and hence that Mrk 501 behaved like an extreme high-frequency- peaked blazar (EHBL) throughout the 2012 observing season. This suggests that being an EHBL may not be a permanent characteristic of a blazar, but rather a state which may change over time. The one-zone synchrotron self-Compton (SSC) scenario can successfully describe the segments of the SED where most energy is emitted, with a significant correlation between the electron energy density and the VHE gamma-ray activity, suggesting that most of the variability may be explained by the injection of high-energy electrons. The one-zone SSC scenario used reproduces the behaviour seen between the measured X-ray and VHE gamma-ray fluxes, and predicts that the correlation becomes stronger with increasing energy of the X-rays. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.04300v2-abstract-full').style.display = 'none'; document.getElementById('1808.04300v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">25 pages, 9 figures, accepted for publication in A&A. Corresponding authors: Gareth Hughes (gareth.hughes@cfa.harvard.edu), David Paneque (dpaneque@mppmu.mpg.de), Amit Shukla (amit.shukla@astro.uni-wuerzburg.de)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 620, A181 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.04607">arXiv:1807.04607</a> <span> [<a href="https://arxiv.org/pdf/1807.04607">pdf</a>, <a href="https://arxiv.org/format/1807.04607">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/aad053">10.3847/2041-8213/aad053 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> VERITAS observations of the BL Lac object TXS 0506+056 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Chromey%2C+A+J">A. J. Chromey</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Gueta%2C+O">O. Gueta</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+C+A">C. A. Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Kaaret%2C+P">P. Kaaret</a>, <a href="/search/astro-ph?searchtype=author&query=Kar%2C+P">P. Kar</a> , et al. (35 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1807.04607v1-abstract-short" style="display: inline;"> On 2017 September 22, the IceCube Neutrino Observatory reported the detection of the high-energy neutrino event \icnu, of potential astrophysical origin. It was soon determined that the neutrino direction was consistent with the location of the gamma-ray blazar \txs~(3FGL J0509.4+0541), which was in an elevated gamma-ray emission state as measured by the \emph{Fermi} satellite. VERITAS observation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.04607v1-abstract-full').style.display = 'inline'; document.getElementById('1807.04607v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.04607v1-abstract-full" style="display: none;"> On 2017 September 22, the IceCube Neutrino Observatory reported the detection of the high-energy neutrino event \icnu, of potential astrophysical origin. It was soon determined that the neutrino direction was consistent with the location of the gamma-ray blazar \txs~(3FGL J0509.4+0541), which was in an elevated gamma-ray emission state as measured by the \emph{Fermi} satellite. VERITAS observations of the neutrino/blazar region started on 2017 September 23 in response to the neutrino alert and continued through 2018 February 6. While no significant very-high-energy (VHE; E $>$ 100 GeV) emission was observed from the blazar by VERITAS in the two-week period immediately following the IceCube alert, TXS 0506+056 was detected by VERITAS with a significance of 5.8 standard deviations ($蟽$) in the full 35-hour data set. The average photon flux of the source during this period was $(8.9 \pm 1.6) \times 10^{-12} \; \mathrm{cm}^{-2} \, \mathrm{s}^{-1}$, or 1.6\% of the Crab Nebula flux, above an energy threshold of 110 GeV, with a soft spectral index of $4.8 \pm 1.3$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.04607v1-abstract-full').style.display = 'none'; document.getElementById('1807.04607v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJL 2018 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1806.04144">arXiv:1806.04144</a> <span> [<a href="https://arxiv.org/pdf/1806.04144">pdf</a>, <a href="https://arxiv.org/format/1806.04144">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aacbd0">10.3847/1538-4357/aacbd0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> HESS J1943+213: An Extreme Blazar Shining Through The Galactic Plane </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+VERITAS+Collaboration"> The VERITAS Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Flinders%2C+A">A. Flinders</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=H%C3%BCtten%2C+M">M. H眉tten</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+C+A">C. A. Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Kaaret%2C+P">P. Kaaret</a>, <a href="/search/astro-ph?searchtype=author&query=Kar%2C+P">P. Kar</a> , et al. (38 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1806.04144v1-abstract-short" style="display: inline;"> HESS J1943+213 is a very-high-energy (VHE; $>$100 GeV) $纬$-ray source in the direction of the Galactic Plane. Studies exploring the classification of the source are converging towards its identification as an extreme synchrotron BL Lac object. Here we present 38 hours of VERITAS observations of HESS J1943+213 taken over two years. The source is detected with $\sim$20 standard deviations significan… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.04144v1-abstract-full').style.display = 'inline'; document.getElementById('1806.04144v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1806.04144v1-abstract-full" style="display: none;"> HESS J1943+213 is a very-high-energy (VHE; $>$100 GeV) $纬$-ray source in the direction of the Galactic Plane. Studies exploring the classification of the source are converging towards its identification as an extreme synchrotron BL Lac object. Here we present 38 hours of VERITAS observations of HESS J1943+213 taken over two years. The source is detected with $\sim$20 standard deviations significance, showing a remarkably stable flux and spectrum in VHE $纬$-rays. Multi-frequency very-long-baseline array (VLBA) observations of the source confirm the extended, jet-like structure previously found in the 1.6 GHz band with European VLBI Network and detect this component in the 4.6 GHz and the 7.3 GHz bands. The radio spectral indices of the core and the jet and the level of polarization derived from the VLBA observations are in a range typical for blazars. Data from VERITAS, $Fermi$-LAT, $Swift$-XRT, FLWO 48$''$ telescope, and archival infrared and hard X-ray observations are used to construct and model the spectral energy distribution (SED) of the source with a synchrotron-self-Compton model. The well-measured $纬$-ray peak of the SED with VERITAS and $Fermi$-LAT provides constraining upper limits on the source redshift. Possible contribution of secondary $纬$-rays from ultra-high-energy cosmic ray-initiated electromagnetic cascades to the $纬$-ray emission is explored, finding that only a segment of the VHE spectrum can be accommodated with this process. A variability search is performed across X-ray and $纬$-ray bands. No statistically significant flux or spectral variability is detected. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.04144v1-abstract-full').style.display = 'none'; document.getElementById('1806.04144v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1803.01266">arXiv:1803.01266</a> <span> [<a href="https://arxiv.org/pdf/1803.01266">pdf</a>, <a href="https://arxiv.org/format/1803.01266">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aab371">10.3847/1538-4357/aab371 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A strong limit on the very-high-energy emission from GRB 150323A </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Flinders%2C+A">A. Flinders</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=H%C3%BCtten%2C+M">M. H眉tten</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+C+A">C. A. Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Kaaret%2C+P">P. Kaaret</a> , et al. (41 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1803.01266v1-abstract-short" style="display: inline;"> On 2015 March 23, VERITAS responded to a $Swift$-BAT detection of a gamma-ray burst, with observations beginning 270 seconds after the onset of BAT emission, and only 135 seconds after the main BAT emission peak. No statistically significant signal is detected above 140 GeV. The VERITAS upper limit on the fluence in a 40 minute integration corresponds to about 1% of the prompt fluence. Our limit i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.01266v1-abstract-full').style.display = 'inline'; document.getElementById('1803.01266v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1803.01266v1-abstract-full" style="display: none;"> On 2015 March 23, VERITAS responded to a $Swift$-BAT detection of a gamma-ray burst, with observations beginning 270 seconds after the onset of BAT emission, and only 135 seconds after the main BAT emission peak. No statistically significant signal is detected above 140 GeV. The VERITAS upper limit on the fluence in a 40 minute integration corresponds to about 1% of the prompt fluence. Our limit is particularly significant since the very-high-energy (VHE) observation started only $\sim$2 minutes after the prompt emission peaked, and $Fermi$-LAT observations of numerous other bursts have revealed that the high-energy emission is typically delayed relative to the prompt radiation and lasts significantly longer. Also, the proximity of GRB~150323A ($z=0.593$) limits the attenuation by the extragalactic background light to $\sim 50$ % at 100-200 GeV. We conclude that GRB 150323A had an intrinsically very weak high-energy afterglow, or that the GeV spectrum had a turnover below $\sim100$ GeV. If the GRB exploded into the stellar wind of a massive progenitor, the VHE non-detection constrains the wind density parameter to be $A\gtrsim 3\times 10^{11}$ g cm$^{-1}$, consistent with a standard Wolf-Rayet progenitor. Alternatively, the VHE emission from the blast wave would be weak in a very tenuous medium such as the ISM, which therefore cannot be ruled out as the environment of GRB 150323A. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.01266v1-abstract-full').style.display = 'none'; document.getElementById('1803.01266v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 March, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 1 figure. Accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1802.10113">arXiv:1802.10113</a> <span> [<a href="https://arxiv.org/pdf/1802.10113">pdf</a>, <a href="https://arxiv.org/format/1802.10113">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aab35c">10.3847/1538-4357/aab35c <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multiwavelength observations of the blazar BL Lacertae: a new fast TeV gamma-ray flare </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brantseg%2C+T">T. Brantseg</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Gunawardhana%2C+I">I. Gunawardhana</a>, <a href="/search/astro-ph?searchtype=author&query=H%C3%BCtten%2C+M">M. H眉tten</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+C+A">C. A. Johnson</a> , et al. (52 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1802.10113v1-abstract-short" style="display: inline;"> Combined with very-long-baseline interferometry measurements, the observations of fast TeV gamma-ray flares probe the structure and emission mechanism of blazar jets. However, only a handful of such flares have been detected to date, and only within the last few years have these flares been observed from lower-frequency-peaked BL~Lac objects and flat-spectrum radio quasars. We report on a fast TeV… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1802.10113v1-abstract-full').style.display = 'inline'; document.getElementById('1802.10113v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1802.10113v1-abstract-full" style="display: none;"> Combined with very-long-baseline interferometry measurements, the observations of fast TeV gamma-ray flares probe the structure and emission mechanism of blazar jets. However, only a handful of such flares have been detected to date, and only within the last few years have these flares been observed from lower-frequency-peaked BL~Lac objects and flat-spectrum radio quasars. We report on a fast TeV gamma-ray flare from the blazar BL~Lacertae observed by VERITAS, with a rise time of $\sim$2.3~hr and a decay time of $\sim$36~min. The peak flux above 200 GeV is $(4.2 \pm 0.6) \times 10^{-6} \;\text{photon} \;\text{m}^{-2}\; \text{s}^{-1}$ measured with a 4-minute-binned light curve, corresponding to $\sim$180\% of the flux which is observed from the Crab Nebula above the same energy threshold. Variability contemporaneous with the TeV gamma-ray flare was observed in GeV gamma-ray, X-ray, and optical flux, as well as in optical and radio polarization. Additionally, a possible moving emission feature with superluminal apparent velocity was identified in VLBA observations at 43 GHz, potentially passing the radio core of the jet around the time of the gamma-ray flare. We discuss the constraints on the size, Lorentz factor, and location of the emitting region of the flare, and the interpretations with several theoretical models which invoke relativistic plasma passing stationary shocks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1802.10113v1-abstract-full').style.display = 'none'; document.getElementById('1802.10113v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 February, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 856 (2018) 95 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1709.07843">arXiv:1709.07843</a> <span>  </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> VERITAS contributions to the 35th International Cosmic Ray Conference </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Fernandez-Alonso%2C+M">M. Fernandez-Alonso</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=H%C3%BCtten%2C+M">M. H眉tten</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+G">G. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Humensky%2C+T+B">T. B. Humensky</a> , et al. (41 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1709.07843v1-abstract-short" style="display: inline;"> Compilation of papers presented by the VERITAS Collaboration at the 35th International Cosmic Ray Conference (ICRC), held July 12 through July 20, 2017 in Busan, South Korea. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1709.07843v1-abstract-full" style="display: none;"> Compilation of papers presented by the VERITAS Collaboration at the 35th International Cosmic Ray Conference (ICRC), held July 12 through July 20, 2017 in Busan, South Korea. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1709.07843v1-abstract-full').style.display = 'none'; document.getElementById('1709.07843v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 September, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">html page. 2017 ICRC, Busan, South Korea. A full list of author affiliations can be found at this link: https://veritas.sao.arizona.edu/conferences/ICRC2017_AuthList.html</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1709.05403">arXiv:1709.05403</a> <span> [<a href="https://arxiv.org/pdf/1709.05403">pdf</a>, <a href="https://arxiv.org/ps/1709.05403">ps</a>, <a href="https://arxiv.org/format/1709.05403">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4365/aa8d76">10.3847/1538-4365/aa8d76 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discovery of very-high-energy emission from RGB J2243+203 and derivation of its redshift upper limit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Griffin%2C+S">S. Griffin</a>, <a href="/search/astro-ph?searchtype=author&query=Grube%2C+J">J. Grube</a>, <a href="/search/astro-ph?searchtype=author&query=Hutten%2C+M">M. Hutten</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a>, <a href="/search/astro-ph?searchtype=author&query=Holder%2C+J">J. Holder</a> , et al. (45 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1709.05403v1-abstract-short" style="display: inline;"> Very-high-energy (VHE; $>$ 100 GeV) gamma-ray emission from the blazar RGB J2243+203 was discovered with the VERITAS Cherenkov telescope array, during the period between 21 and 24 December 2014. The VERITAS energy spectrum from this source can be fit by a power law with a photon index of $4.6 \pm 0.5$, and a flux normalization at 0.15 TeV of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1709.05403v1-abstract-full').style.display = 'inline'; document.getElementById('1709.05403v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1709.05403v1-abstract-full" style="display: none;"> Very-high-energy (VHE; $>$ 100 GeV) gamma-ray emission from the blazar RGB J2243+203 was discovered with the VERITAS Cherenkov telescope array, during the period between 21 and 24 December 2014. The VERITAS energy spectrum from this source can be fit by a power law with a photon index of $4.6 \pm 0.5$, and a flux normalization at 0.15 TeV of $(6.3 \pm 1.1) \times 10^{-10} ~ \textrm{cm}^{-2} \textrm{s}^{-1} \textrm{TeV}^{-1}$. The integrated \textit{Fermi}-LAT flux from 1 GeV to 100 GeV during the VERITAS detection is $(4.1 \pm 0.8) \times 10^{\textrm{-8}} ~\textrm{cm}^{\textrm{-2}}\textrm{s}^{\textrm{-1}}$, which is an order of magnitude larger than the four-year-averaged flux in the same energy range reported in the 3FGL catalog, ($4.0 \pm 0.1 \times 10^{\textrm{-9}} ~ \textrm{cm}^{\textrm{-2}}\textrm{s}^{\textrm{-1}}$). The detection with VERITAS triggered observations in the X-ray band with the \textit{Swift}-XRT. However, due to scheduling constraints \textit{Swift}-XRT observations were performed 67 hours after the VERITAS detection, not simultaneous with the VERITAS observations. The observed X-ray energy spectrum between 2 keV and 10 keV can be fitted with a power-law with a spectral index of $2.7 \pm 0.2$, and the integrated photon flux in the same energy band is $(3.6 \pm 0.6) \times 10^{-13} ~\textrm{cm}^{-2} \textrm{s}^{-1}$. EBL model-dependent upper limits of the blazar redshift have been derived. Depending on the EBL model used, the upper limit varies in the range from z $<~0.9$ to z $<~1.1$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1709.05403v1-abstract-full').style.display = 'none'; document.getElementById('1709.05403v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 September, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2017. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1708.02829">arXiv:1708.02829</a> <span> [<a href="https://arxiv.org/pdf/1708.02829">pdf</a>, <a href="https://arxiv.org/format/1708.02829">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx1756">10.1093/mnras/stx1756 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Very-High-Energy $纬$-Ray Observations of the Blazar 1ES 2344+514 with VERITAS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Allen%2C+C">C. Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Bourbeau%2C+E">E. Bourbeau</a>, <a href="/search/astro-ph?searchtype=author&query=Brose%2C+R">R. Brose</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Fernandez-Alonso%2C+M">M. Fernandez-Alonso</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Flinders%2C+A">A. Flinders</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a> , et al. (57 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1708.02829v1-abstract-short" style="display: inline;"> We present very-high-energy $纬$-ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above background of $20.8蟽$ in $47.2$ hours (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Usi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.02829v1-abstract-full').style.display = 'inline'; document.getElementById('1708.02829v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1708.02829v1-abstract-full" style="display: none;"> We present very-high-energy $纬$-ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above background of $20.8蟽$ in $47.2$ hours (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Using these observations the temporal properties of 1ES 2344+514 are studied on short and long times scales. We fit a constant flux model to nightly- and seasonally-binned light curves and apply a fractional variability test, to determine the stability of the source on different timescales. We reject the constant-flux model for the 2007-2008 and 2014-2015 nightly-binned light curves and for the long-term seasonally-binned light curve at the $> 3蟽$ level. The spectra of the time-averaged emission before and after correction for attenuation by the extragalactic background light are obtained. The observed time-averaged spectrum above 200 GeV is satisfactorily fitted (${蠂^2/NDF = 7.89/6}$) by a power-law function with index $螕= 2.46 \pm 0.06_{stat} \pm 0.20_{sys} $ and extends to at least 8 TeV. The extragalactic-background-light-deabsorbed spectrum is adequately fit (${蠂^2/NDF = 6.73/6}$) by a power-law function with index $螕= 2.15 \pm 0.06_{stat} \pm 0.20_{sys} $ while an F-test indicates that the power-law with exponential cutoff function provides a marginally-better fit ($蠂^2/NDF $ = $2.56 / 5 $) at the 2.1$蟽$ level. The source location is found to be consistent with the published radio location and its spatial extent is consistent with a point source. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.02829v1-abstract-full').style.display = 'none'; document.getElementById('1708.02829v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 2 figures. Published in Monthly Notices of the Royal Astronomical Society</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Monthly Notices of the Royal Astronomical Society, Volume 471, Issue 2, 21 October 2017, Pages 2117-2123 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1703.01307">arXiv:1703.01307</a> <span> [<a href="https://arxiv.org/pdf/1703.01307">pdf</a>, <a href="https://arxiv.org/format/1703.01307">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.astropartphys.2017.03.001">10.1016/j.astropartphys.2017.03.001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gamma-ray Observations Under Bright Moonlight with VERITAS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Bourbeau%2C+E">E. Bourbeau</a>, <a href="/search/astro-ph?searchtype=author&query=Bouvier%2C+A">A. Bouvier</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Daniel%2C+M+K">M. K. Daniel</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Griffin%2C+S">S. Griffin</a>, <a href="/search/astro-ph?searchtype=author&query=Hanna%2C+D">D. Hanna</a>, <a href="/search/astro-ph?searchtype=author&query=Hervet%2C+O">O. Hervet</a> , et al. (40 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1703.01307v1-abstract-short" style="display: inline;"> Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive photomultiplier tube (PMT) cameras. Exposure to high levels of background illumination degrades the efficiency of and potentially destroys these photo-detectors over time, so IACTs cannot be operated in the same configuration in the presence of bright moonlight as under dark skies. Since September 2012, observations have… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.01307v1-abstract-full').style.display = 'inline'; document.getElementById('1703.01307v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1703.01307v1-abstract-full" style="display: none;"> Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive photomultiplier tube (PMT) cameras. Exposure to high levels of background illumination degrades the efficiency of and potentially destroys these photo-detectors over time, so IACTs cannot be operated in the same configuration in the presence of bright moonlight as under dark skies. Since September 2012, observations have been carried out with the VERITAS IACTs under bright moonlight (defined as about three times the night-sky-background (NSB) of a dark extragalactic field, typically occurring when Moon illumination > 35%) in two observing modes, firstly by reducing the voltage applied to the PMTs and, secondly, with the addition of ultra-violet (UV) bandpass filters to the cameras. This has allowed observations at up to about 30 times previous NSB levels (around 80% Moon illumination), resulting in 30% more observing time between the two modes over the course of a year. These additional observations have already allowed for the detection of a flare from the 1ES 1727+502 and for an observing program targeting a measurement of the cosmic-ray positron fraction. We provide details of these new observing modes and their performance relative to the standard VERITAS observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.01307v1-abstract-full').style.display = 'none'; document.getElementById('1703.01307v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2017. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1701.01067">arXiv:1701.01067</a> <span> [<a href="https://arxiv.org/pdf/1701.01067">pdf</a>, <a href="https://arxiv.org/ps/1701.01067">ps</a>, <a href="https://arxiv.org/format/1701.01067">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/836/2/205">10.3847/1538-4357/836/2/205 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A luminous and isolated gamma-ray flare from the blazar B2 1215+30 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=VERITAS+Collaboration"> VERITAS Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Griffin%2C+S">S. Griffin</a> , et al. (62 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1701.01067v1-abstract-short" style="display: inline;"> B2 1215+30 is a BL Lac-type blazar that was first detected at TeV energies by the MAGIC atmospheric Cherenkov telescopes, and subsequently confirmed by the VERITAS observatory with data collected between 2009 and 2012. In 2014 February 08, VERITAS detected a large-amplitude flare from B2 1215+30 during routine monitoring observations of the blazar 1ES 1218+304, located in the same field of view. T… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.01067v1-abstract-full').style.display = 'inline'; document.getElementById('1701.01067v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1701.01067v1-abstract-full" style="display: none;"> B2 1215+30 is a BL Lac-type blazar that was first detected at TeV energies by the MAGIC atmospheric Cherenkov telescopes, and subsequently confirmed by the VERITAS observatory with data collected between 2009 and 2012. In 2014 February 08, VERITAS detected a large-amplitude flare from B2 1215+30 during routine monitoring observations of the blazar 1ES 1218+304, located in the same field of view. The TeV flux reached 2.4 times the Crab Nebula flux with a variability timescale of < 3.6 h. Multiwavelength observations with Fermi-LAT, Swift, and the Tuorla observatory revealed a correlated high GeV flux state and no significant optical counterpart to the flare, with a spectral energy distribution where the gamma-ray luminosity exceeds the synchrotron luminosity. When interpreted in the framework of a one-zone leptonic model, the observed emission implies a high degree of beaming, with Doppler factor > 10, and an electron population with spectral index < 2.3. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.01067v1-abstract-full').style.display = 'none'; document.getElementById('1701.01067v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 January, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 3 figures, accepted for publication in The Astrophysical Journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ, 836, 205 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1612.09472">arXiv:1612.09472</a> <span> [<a href="https://arxiv.org/pdf/1612.09472">pdf</a>, <a href="https://arxiv.org/ps/1612.09472">ps</a>, <a href="https://arxiv.org/format/1612.09472">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201629540">10.1051/0004-6361/201629540 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ahnen%2C+M+L">M. L. Ahnen</a>, <a href="/search/astro-ph?searchtype=author&query=Ansoldi%2C+S">S. Ansoldi</a>, <a href="/search/astro-ph?searchtype=author&query=Antonelli%2C+L+A">L. A. Antonelli</a>, <a href="/search/astro-ph?searchtype=author&query=Antoranz%2C+P">P. Antoranz</a>, <a href="/search/astro-ph?searchtype=author&query=Babic%2C+A">A. Babic</a>, <a href="/search/astro-ph?searchtype=author&query=Banerjee%2C+B">B. Banerjee</a>, <a href="/search/astro-ph?searchtype=author&query=Bangale%2C+P">P. Bangale</a>, <a href="/search/astro-ph?searchtype=author&query=de+Almeida%2C+U+B">U. Barres de Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=Barrio%2C+J+A">J. A. Barrio</a>, <a href="/search/astro-ph?searchtype=author&query=Gonz%C3%A1lez%2C+J+B">J. Becerra Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Bednarek%2C+W">W. Bednarek</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Biasuzzi%2C+B">B. Biasuzzi</a>, <a href="/search/astro-ph?searchtype=author&query=Biland%2C+A">A. Biland</a>, <a href="/search/astro-ph?searchtype=author&query=Blanch%2C+O">O. Blanch</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnefoy%2C+S">S. Bonnefoy</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">G. Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Borracci%2C+F">F. Borracci</a>, <a href="/search/astro-ph?searchtype=author&query=Bretz%2C+T">T. Bretz</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Carosi%2C+A">A. Carosi</a>, <a href="/search/astro-ph?searchtype=author&query=Chatterjee%2C+A">A. Chatterjee</a>, <a href="/search/astro-ph?searchtype=author&query=Clavero%2C+R">R. Clavero</a>, <a href="/search/astro-ph?searchtype=author&query=Colin%2C+P">P. Colin</a> , et al. (268 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1612.09472v1-abstract-short" style="display: inline;"> We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1 which includes, among other instruments, MAGIC, VERITAS, Whipple 10-m, Fermi-LAT, RXTE, Swift, GASP-WEBT and VLBA. We find an increase in the fractional variability with energy, while no significant interband correlations of flux… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.09472v1-abstract-full').style.display = 'inline'; document.getElementById('1612.09472v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1612.09472v1-abstract-full" style="display: none;"> We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1 which includes, among other instruments, MAGIC, VERITAS, Whipple 10-m, Fermi-LAT, RXTE, Swift, GASP-WEBT and VLBA. We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found in the acquired data set. The higher variability in the very high energy (>100 GeV, VHE) gamma-ray emission and the lack of correlation with the X-ray emission indicate that the highest-energy electrons that are responsible for the VHE gamma-rays do not make a dominant contribution to the ~1 keV emission. Alternatively, there could be a very variable component contributing to the VHE gamma-ray emission in addition to that coming from the synchrotron self-Compton (SSC) scenarios. The space of SSC model parameters is probed following a dedicated grid-scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model-to-data agreement in the individual model parameters. We find that there is some degeneracy in both the one-zone and the two-zone SSC scenarios that were probed, with several combinations of model parameters yielding a similar model-to-data agreement, and some parameters better constrained than others. The SSC model grid-scan shows that the flaring activity around 2009 May 22 cannot be modeled adequately with a one-zone SSC scenario, while it can be suitably described within a two-independent-zone SSC scenario. The observation of an electric vector polarization angle rotation coincident with the gamma-ray flare from 2009 May 1 resembles those reported previously for low frequency peaked blazars, hence suggesting that there are many similarities in the flaring mechanisms of blazars with different jet properties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.09472v1-abstract-full').style.display = 'none'; document.getElementById('1612.09472v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 December, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">33 pages, 15 figures, accepted for publication in A&A. Corresponding authors: Marlene Doert (marlene.doert@tu-dortmund.de) and David Paneque (dpaneque@mppmu.mpg.de)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 603, A31 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1610.01814">arXiv:1610.01814</a> <span> [<a href="https://arxiv.org/pdf/1610.01814">pdf</a>, <a href="https://arxiv.org/ps/1610.01814">ps</a>, <a href="https://arxiv.org/format/1610.01814">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1748-0221/11/11/P11009">10.1088/1748-0221/11/11/P11009 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Very High-Energy Gamma-Ray Follow-Up Program Using Neutrino Triggers from IceCube </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=IceCube+Collaboration"> IceCube Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Aartsen%2C+M+G">M. G. Aartsen</a>, <a href="/search/astro-ph?searchtype=author&query=Abraham%2C+K">K. Abraham</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+J">J. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Aguilar%2C+J+A">J. A. Aguilar</a>, <a href="/search/astro-ph?searchtype=author&query=Ahlers%2C+M">M. Ahlers</a>, <a href="/search/astro-ph?searchtype=author&query=Ahrens%2C+M">M. Ahrens</a>, <a href="/search/astro-ph?searchtype=author&query=Altmann%2C+D">D. Altmann</a>, <a href="/search/astro-ph?searchtype=author&query=Andeen%2C+K">K. Andeen</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+T">T. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Ansseau%2C+I">I. Ansseau</a>, <a href="/search/astro-ph?searchtype=author&query=Anton%2C+G">G. Anton</a>, <a href="/search/astro-ph?searchtype=author&query=Archinger%2C+M">M. Archinger</a>, <a href="/search/astro-ph?searchtype=author&query=Arguelles%2C+C">C. Arguelles</a>, <a href="/search/astro-ph?searchtype=author&query=Auffenberg%2C+J">J. Auffenberg</a>, <a href="/search/astro-ph?searchtype=author&query=Axani%2C+S">S. Axani</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+X">X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Barwick%2C+S+W">S. W. Barwick</a>, <a href="/search/astro-ph?searchtype=author&query=Baum%2C+V">V. Baum</a>, <a href="/search/astro-ph?searchtype=author&query=Bay%2C+R">R. Bay</a>, <a href="/search/astro-ph?searchtype=author&query=Beatty%2C+J+J">J. J. Beatty</a>, <a href="/search/astro-ph?searchtype=author&query=Becker-Tjus%2C+J">J. Becker-Tjus</a>, <a href="/search/astro-ph?searchtype=author&query=Becker%2C+K+-">K. -H. Becker</a>, <a href="/search/astro-ph?searchtype=author&query=BenZvi%2C+S">S. BenZvi</a> , et al. (519 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1610.01814v3-abstract-short" style="display: inline;"> We describe and report the status of a neutrino-triggered program in IceCube that generates real-time alerts for gamma-ray follow-up observations by atmospheric-Cherenkov telescopes (MAGIC and VERITAS). While IceCube is capable of monitoring the whole sky continuously, high-energy gamma-ray telescopes have restricted fields of view and in general are unlikely to be observing a potential neutrino-f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.01814v3-abstract-full').style.display = 'inline'; document.getElementById('1610.01814v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1610.01814v3-abstract-full" style="display: none;"> We describe and report the status of a neutrino-triggered program in IceCube that generates real-time alerts for gamma-ray follow-up observations by atmospheric-Cherenkov telescopes (MAGIC and VERITAS). While IceCube is capable of monitoring the whole sky continuously, high-energy gamma-ray telescopes have restricted fields of view and in general are unlikely to be observing a potential neutrino-flaring source at the time such neutrinos are recorded. The use of neutrino-triggered alerts thus aims at increasing the availability of simultaneous multi-messenger data during potential neutrino flaring activity, which can increase the discovery potential and constrain the phenomenological interpretation of the high-energy emission of selected source classes (e.g. blazars). The requirements of a fast and stable online analysis of potential neutrino signals and its operation are presented, along with first results of the program operating between 14 March 2012 and 31 December 2015. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.01814v3-abstract-full').style.display = 'none'; document.getElementById('1610.01814v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">accepted for publication in JINST</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2016 JINST 11 P11009 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.01692">arXiv:1609.01692</a> <span> [<a href="https://arxiv.org/pdf/1609.01692">pdf</a>, <a href="https://arxiv.org/format/1609.01692">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/0004-637X/831/2/193">10.3847/0004-637X/831/2/193 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Search for Very High-Energy Gamma Rays from the Missing Link Binary Pulsar J1023+0038 with VERITAS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Biteau%2C+J">J. Biteau</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Flinders%2C+A">A. Flinders</a>, <a href="/search/astro-ph?searchtype=author&query=Fortin%2C+P">P. Fortin</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a> , et al. (60 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1609.01692v1-abstract-short" style="display: inline;"> The binary millisecond radio pulsar PSR J1023+0038 exhibits many characteristics similar to the gamma-ray binary system PSR B1259--63/LS 2883, making it an ideal candidate for the study of high-energy non-thermal emission. It has been the subject of multi-wavelength campaigns following the disappearance of the pulsed radio emission in 2013 June, which revealed the appearance of an accretion disk a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.01692v1-abstract-full').style.display = 'inline'; document.getElementById('1609.01692v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.01692v1-abstract-full" style="display: none;"> The binary millisecond radio pulsar PSR J1023+0038 exhibits many characteristics similar to the gamma-ray binary system PSR B1259--63/LS 2883, making it an ideal candidate for the study of high-energy non-thermal emission. It has been the subject of multi-wavelength campaigns following the disappearance of the pulsed radio emission in 2013 June, which revealed the appearance of an accretion disk around the neutron star. We present the results of very high-energy gamma-ray observations carried out by VERITAS before and after this change of state. Searches for steady and pulsed emission of both data sets yield no significant gamma-ray signal above 100 GeV, and upper limits are given for both a steady and pulsed gamma-ray flux. These upper limits are used to constrain the magnetic field strength in the shock region of the PSR J1023+0038 system. Assuming that very high-energy gamma rays are produced via an inverse-Compton mechanism in the shock region, we constrain the shock magnetic field to be greater than $\sim$2 G before the disappearance of the radio pulsar and greater than $\sim$10 G afterwards. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.01692v1-abstract-full').style.display = 'none'; document.getElementById('1609.01692v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 3 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.02769">arXiv:1608.02769</a> <span> [<a href="https://arxiv.org/pdf/1608.02769">pdf</a>, <a href="https://arxiv.org/ps/1608.02769">ps</a>, <a href="https://arxiv.org/format/1608.02769">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stw1319">10.1093/mnras/stw1319 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discovery of Very High Energy Gamma Rays from 1ES 1440+122 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=VERITAS+Collaboration"> VERITAS Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Behera%2C+B">B. Behera</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Boettcher%2C+M">M. Boettcher</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Collins-Hughes%2C+E">E. Collins-Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a> , et al. (65 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1608.02769v1-abstract-short" style="display: inline;"> The BL Lacertae object 1ES 1440+122 was observed in the energy range from 85 GeV to 30 TeV by the VERITAS array of imaging atmospheric Cherenkov telescopes. The observations, taken between 2008 May and 2010 June and totalling 53 hours, resulted in the discovery of $纬$-ray emission from the blazar, which has a redshift $z$=0.163. 1ES 1440+122 is detected at a statistical significance of 5.5 standar… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.02769v1-abstract-full').style.display = 'inline'; document.getElementById('1608.02769v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.02769v1-abstract-full" style="display: none;"> The BL Lacertae object 1ES 1440+122 was observed in the energy range from 85 GeV to 30 TeV by the VERITAS array of imaging atmospheric Cherenkov telescopes. The observations, taken between 2008 May and 2010 June and totalling 53 hours, resulted in the discovery of $纬$-ray emission from the blazar, which has a redshift $z$=0.163. 1ES 1440+122 is detected at a statistical significance of 5.5 standard deviations above the background with an integral flux of (2.8$\pm0.7_{\mathrm{stat}}\pm0.8_{\mathrm{sys}}$) $\times$ 10$^{-12}$ cm$^{-2}$ s$^{-1}$ (1.2\% of the Crab Nebula's flux) above 200 GeV. The measured spectrum is described well by a power law from 0.2 TeV to 1.3 TeV with a photon index of 3.1 $\pm$ 0.4$_{\mathrm{stat}}$ $\pm$ 0.2$_{\mathrm{sys}}$. Quasi-simultaneous multi-wavelength data from the Fermi Large Area Telescope (0.3--300 GeV) and the Swift X-ray Telescope (0.2--10 keV) are additionally used to model the properties of the emission region. A synchrotron self-Compton model produces a good representation of the multi-wavelength data. Adding an external-Compton or a hadronic component also adequately describes the data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.02769v1-abstract-full').style.display = 'none'; document.getElementById('1608.02769v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures. Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.01569">arXiv:1608.01569</a> <span> [<a href="https://arxiv.org/pdf/1608.01569">pdf</a>, <a href="https://arxiv.org/format/1608.01569">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201628744">10.1051/0004-6361/201628744 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Very High Energy outburst of Markarian 501 in May 2009 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Arlen%2C+T">T. Arlen</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Behera%2C+B">B. Behera</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Bouvier%2C+A">A. Bouvier</a>, <a href="/search/astro-ph?searchtype=author&query=B%C3%B6ttcher%2C+M">M. B枚ttcher</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Cesarini%2C+A">A. Cesarini</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Collins-Hughes%2C+E">E. Collins-Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a> , et al. (86 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1608.01569v1-abstract-short" style="display: inline;"> The very high energy (VHE; E $>$ 100 GeV) blazar Markarian 501 was observed between April 17 and May 5 (MJD 54938--54956), 2009, as part of an extensive multi-wavelength campaign from radio to VHE. Strong VHE $纬$-ray activity was detected on May 1st with Whipple and VERITAS, when the flux (E $>$ 400 GeV) increased to 10 times the pre-flare baseline flux (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.01569v1-abstract-full').style.display = 'inline'; document.getElementById('1608.01569v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.01569v1-abstract-full" style="display: none;"> The very high energy (VHE; E $>$ 100 GeV) blazar Markarian 501 was observed between April 17 and May 5 (MJD 54938--54956), 2009, as part of an extensive multi-wavelength campaign from radio to VHE. Strong VHE $纬$-ray activity was detected on May 1st with Whipple and VERITAS, when the flux (E $>$ 400 GeV) increased to 10 times the pre-flare baseline flux ($3.9{\times 10^{-11}}~{\rm ph~cm^{-2}~s^{-1}}$), reaching five times the flux of the Crab Nebula. This coincided with a decrease in the optical polarization and a rotation of the polarization angle by 15$^{\circ}$. This VHE flare showed a fast flux variation with an increase of a factor $\sim$4 in 25 minutes, and a falling time of $\sim$50 minutes. We present the observations of the quiescent state previous to the flare and of the high state after the flare, focusing on the flux and spectral variability from Whipple, VERITAS, Fermi-LAT, RXTE, and Swift combined with optical and radio data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.01569v1-abstract-full').style.display = 'none'; document.getElementById('1608.01569v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 10 figures. Accepted for publication in Astronomy and Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 594, A76 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1603.07286">arXiv:1603.07286</a> <span> [<a href="https://arxiv.org/pdf/1603.07286">pdf</a>, <a href="https://arxiv.org/ps/1603.07286">ps</a>, <a href="https://arxiv.org/format/1603.07286">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stw664">10.1093/mnras/stw664 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> VERITAS and Multiwavelength Observations of the BL Lacertae Object 1ES 1741+196 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=VERITAS+Collaboration"> VERITAS Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Biteau%2C+J">J. Biteau</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a> , et al. (63 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1603.07286v1-abstract-short" style="display: inline;"> We present results from multiwavelength observations of the BL Lacertae object 1ES 1741+196, including results in the very-high-energy $纬$-ray regime using the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The VERITAS time-averaged spectrum, measured above 180 GeV, is well-modelled by a power law with a spectral index of $2.7\pm0.7_{\mathrm{stat}}\pm0.2_{\mathrm{syst}}$. The i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.07286v1-abstract-full').style.display = 'inline'; document.getElementById('1603.07286v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1603.07286v1-abstract-full" style="display: none;"> We present results from multiwavelength observations of the BL Lacertae object 1ES 1741+196, including results in the very-high-energy $纬$-ray regime using the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The VERITAS time-averaged spectrum, measured above 180 GeV, is well-modelled by a power law with a spectral index of $2.7\pm0.7_{\mathrm{stat}}\pm0.2_{\mathrm{syst}}$. The integral flux above 180 GeV is $(3.9\pm0.8_{\mathrm{stat}}\pm1.0_{\mathrm{syst}})\times 10^{-8}$ m$^{-2}$ s$^{-1}$, corresponding to 1.6% of the Crab Nebula flux on average. The multiwavelength spectral energy distribution of the source suggests that 1ES 1741+196 is an extreme-high-frequency-peaked BL Lacertae object. The observations analysed in this paper extend over a period of six years, during which time no strong flares were observed in any band. This analysis is therefore one of the few characterizations of a blazar in a non-flaring state. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.07286v1-abstract-full').style.display = 'none'; document.getElementById('1603.07286v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 March, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 5 figures. Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1603.02410">arXiv:1603.02410</a> <span> [<a href="https://arxiv.org/pdf/1603.02410">pdf</a>, <a href="https://arxiv.org/format/1603.02410">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/0004-6256/151/6/142">10.3847/0004-6256/151/6/142 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Upper limits from five years of blazar observations with the VERITAS Cherenkov telescopes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Biteau%2C+J">J. Biteau</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Fortin%2C+P">P. Fortin</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Griffin%2C+S">S. Griffin</a> , et al. (56 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1603.02410v1-abstract-short" style="display: inline;"> Between the beginning of its full-scale scientific operations in 2007 and 2012, the VERITAS Cherenkov telescope array observed more than 130 blazars; of these, 26 were detected as very-high-energy (VHE; E>100 GeV) 纬-ray sources. In this work, we present the analysis results of a sample of 114 undetected objects. The observations constitute a total live-time of ~570 hours. The sample includes sever… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.02410v1-abstract-full').style.display = 'inline'; document.getElementById('1603.02410v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1603.02410v1-abstract-full" style="display: none;"> Between the beginning of its full-scale scientific operations in 2007 and 2012, the VERITAS Cherenkov telescope array observed more than 130 blazars; of these, 26 were detected as very-high-energy (VHE; E>100 GeV) 纬-ray sources. In this work, we present the analysis results of a sample of 114 undetected objects. The observations constitute a total live-time of ~570 hours. The sample includes several unidentified Fermi-Large Area Telescope (LAT) sources (located at high Galactic latitude) as well as all the sources from the second Fermi-LAT catalog which are contained within the field of view of the VERITAS observations. We have also performed optical spectroscopy measurements in order to estimate the redshift of some of these blazars that do not have a spectroscopic distance estimate. We present new optical spectra from the Kast instrument on the Shane telescope at the Lick observatory for 18 blazars included in this work, which allowed for the successful measurement or constraint on the redshift of four of them. For each of the blazars included in our sample we provide the flux upper limit in the VERITAS energy band. We also study the properties of the significance distributions and we present the result of a stacked analysis of the data-set, which shows a 4 蟽 excess. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.02410v1-abstract-full').style.display = 'none'; document.getElementById('1603.02410v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 March, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages; accepted for publication in The Astronomical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.08522">arXiv:1602.08522</a> <span> [<a href="https://arxiv.org/pdf/1602.08522">pdf</a>, <a href="https://arxiv.org/format/1602.08522">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/0004-637X/821/2/129">10.3847/0004-637X/821/2/129 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> TeV Gamma-ray Observations of The Galactic Center Ridge By VERITAS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Collins-Hughes%2C+E">E. Collins-Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Flinders%2C+A">A. Flinders</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a>, <a href="/search/astro-ph?searchtype=author&query=Griffin%2C+S">S. Griffin</a>, <a href="/search/astro-ph?searchtype=author&query=Grube%2C+J">J. Grube</a>, <a href="/search/astro-ph?searchtype=author&query=Gyuk%2C+G">G. Gyuk</a> , et al. (51 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1602.08522v1-abstract-short" style="display: inline;"> The Galactic Center Ridge has been observed extensively in the past by both GeV and TeV gamma-ray instruments revealing a wealth of structure, including a diffuse component as well as the point sources G0.9+0.1 (a composite supernova remnant) and Sgr A* (believed to be associated with the supermassive black hole located at the center of our Galaxy). Previous very high energy (VHE) gamma-ray observ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08522v1-abstract-full').style.display = 'inline'; document.getElementById('1602.08522v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.08522v1-abstract-full" style="display: none;"> The Galactic Center Ridge has been observed extensively in the past by both GeV and TeV gamma-ray instruments revealing a wealth of structure, including a diffuse component as well as the point sources G0.9+0.1 (a composite supernova remnant) and Sgr A* (believed to be associated with the supermassive black hole located at the center of our Galaxy). Previous very high energy (VHE) gamma-ray observations with the H.E.S.S. experiment have also detected an extended TeV gamma-ray component along the Galactic plane in the >300 GeV gamma-ray regime. Here we report on observations of the Galactic Center Ridge from 2010-2014 by the VERITAS telescope array in the >2 TeV energy range. From these observations we 1.) provide improved measurements of the differential energy spectrum for Sgr A* in the >2 TeV gamma-ray regime, 2.) provide a detection in the >2 TeV gamma-ray emission from the composite SNR G0.9+0.1 and an improved determination of its multi-TeV gamma-ray energy spectrum, 3.) report on the detection of VER J1746-289, a localized enhancement of >2 TeV gamma-ray emission along the Galactic plane. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08522v1-abstract-full').style.display = 'none'; document.getElementById('1602.08522v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 5 figures, Accepted for Publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.00987">arXiv:1602.00987</a> <span> [<a href="https://arxiv.org/pdf/1602.00987">pdf</a>, <a href="https://arxiv.org/format/1602.00987">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8205/818/2/L33">10.3847/2041-8205/818/2/L33 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Search for Brief Optical Flashes Associated with the SETI Target KIC 8462852 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Fegan%2C+D+J">D. J. Fegan</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Fortin%2C+P">P. Fortin</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a> , et al. (56 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1602.00987v2-abstract-short" style="display: inline;"> The F-type star KIC 8462852 has recently been identified as an exceptional target for SETI (search for extraterrestrial intelligence) observations. We describe an analysis methodology for optical SETI, which we have used to analyse nine hours of serendipitous archival observations of KIC 8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacon… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.00987v2-abstract-full').style.display = 'inline'; document.getElementById('1602.00987v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.00987v2-abstract-full" style="display: none;"> The F-type star KIC 8462852 has recently been identified as an exceptional target for SETI (search for extraterrestrial intelligence) observations. We describe an analysis methodology for optical SETI, which we have used to analyse nine hours of serendipitous archival observations of KIC 8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacons, above a pulse intensity at the Earth of approximately 1 photon per m^2, is found. We also discuss the potential use of imaging atmospheric Cherenkov telescope arrays in searching for extremely short duration optical transients in general. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.00987v2-abstract-full').style.display = 'none'; document.getElementById('1602.00987v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in ApJ Letters. Fixed a minor error in the title</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1601.01812">arXiv:1601.01812</a> <span> [<a href="https://arxiv.org/pdf/1601.01812">pdf</a>, <a href="https://arxiv.org/format/1601.01812">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8205/817/1/L7">10.3847/2041-8205/817/1/L7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exceptionally bright TeV flares from the binary LS I +61$^\circ$ 303 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=VERITAS+Collaboration"> VERITAS Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V. Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Collins-Hughes%2C+E">E. Collins-Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a> , et al. (64 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1601.01812v1-abstract-short" style="display: inline;"> The TeV binary system LS I +61$^\circ$ 303 is known for its regular, non-thermal emission pattern which traces the orbital period of the compact object in its 26.5 day orbit around its B0 Ve star companion. The system typically presents elevated TeV emission around apastron passage with flux levels between 5% and 15% of the steady flux from the Crab Nebula (> 300 GeV). In this article, VERITAS obs… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.01812v1-abstract-full').style.display = 'inline'; document.getElementById('1601.01812v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1601.01812v1-abstract-full" style="display: none;"> The TeV binary system LS I +61$^\circ$ 303 is known for its regular, non-thermal emission pattern which traces the orbital period of the compact object in its 26.5 day orbit around its B0 Ve star companion. The system typically presents elevated TeV emission around apastron passage with flux levels between 5% and 15% of the steady flux from the Crab Nebula (> 300 GeV). In this article, VERITAS observations of LS I +61$^\circ$ 303 taken in late 2014 are presented, during which bright TeV flares around apastron at flux levels peaking above 30% of the Crab Nebula flux were detected. This is the brightest such activity from this source ever seen in the TeV regime. The strong outbursts have rise and fall times of less than a day. The short timescale of the flares, in conjunction with the observation of 10 TeV photons from LS I +61$^\circ$ 303 during the flares, provides constraints on the properties of the accelerator in the source. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.01812v1-abstract-full').style.display = 'none'; document.getElementById('1601.01812v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 January, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 2 figures. Accepted for publication by ApJL</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 817 L7 2016 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1512.04434">arXiv:1512.04434</a> <span> [<a href="https://arxiv.org/pdf/1512.04434">pdf</a>, <a href="https://arxiv.org/format/1512.04434">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/2041-8205/815/2/L22">10.1088/2041-8205/815/2/L22 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gamma rays from the quasar PKS 1441+25: story of an escape </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Biteau%2C+J">J. Biteau</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Coppi%2C+P">P. Coppi</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a> , et al. (81 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1512.04434v1-abstract-short" style="display: inline;"> Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints on the diffuse radiation fields that fill the Universe. The detection of significant emission above 100 GeV from a distant quasar would show that some of the radiated gamma rays escape pair-production interactions with low-energy photons, be it the extragalactic background light (EB… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.04434v1-abstract-full').style.display = 'inline'; document.getElementById('1512.04434v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1512.04434v1-abstract-full" style="display: none;"> Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints on the diffuse radiation fields that fill the Universe. The detection of significant emission above 100 GeV from a distant quasar would show that some of the radiated gamma rays escape pair-production interactions with low-energy photons, be it the extragalactic background light (EBL), or the radiation near the supermassive black hole lying at the jet's base. VERITAS detected gamma-ray emission up to 200 GeV from PKS 1441+25 (z=0.939) during April 2015, a period of high activity across all wavelengths. This observation of PKS 1441+25 suggests that the emission region is located thousands of Schwarzschild radii away from the black hole. The gamma-ray detection also sets a stringent upper limit on the near-ultraviolet to near-infrared EBL intensity, suggesting that galaxy surveys have resolved most, if not all, of the sources of the EBL at these wavelengths. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.04434v1-abstract-full').style.display = 'none'; document.getElementById('1512.04434v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 December, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 3 figures, published in ApJ Letters 815, L22 (2015)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1510.01639">arXiv:1510.01639</a> <span>  </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> VERITAS Collaboration Contributions to the 34th International Cosmic Ray Conference </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+VERITAS+Collaboration"> The VERITAS Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Biteau%2C+J">J. Biteau</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Collins-Hughes%2C+E">E. Collins-Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Coppi%2C+P">P. Coppi</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dwarkadas%2C+V+V">V. V. Dwarkadas</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a> , et al. (68 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1510.01639v1-abstract-short" style="display: inline;"> Compilation of papers presented by the VERITAS Collaboration at the 34th International Cosmic Ray Conference (ICRC), held July 30 through August 6, 2015 in The Hague, The Netherlands. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1510.01639v1-abstract-full" style="display: none;"> Compilation of papers presented by the VERITAS Collaboration at the 34th International Cosmic Ray Conference (ICRC), held July 30 through August 6, 2015 in The Hague, The Netherlands. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.01639v1-abstract-full').style.display = 'none'; document.getElementById('1510.01639v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">1 html page. 2015 ICRC, The Hague, The Netherlands. A full list of author affiliations can be found at this link: http://veritas.sao.arizona.edu/conferences/authors?icrc2015</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1510.01269">arXiv:1510.01269</a> <span> [<a href="https://arxiv.org/pdf/1510.01269">pdf</a>, <a href="https://arxiv.org/format/1510.01269">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> Science Highlights from VERITAS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Staszak%2C+D">D. Staszak</a>, <a href="/search/astro-ph?searchtype=author&query=Abeysekara%2C+A+U">A. U. Abeysekara</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Biteau%2C+J">J. Biteau</a>, <a href="/search/astro-ph?searchtype=author&query=Buchovecky%2C+M">M. Buchovecky</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Christiansen%2C+J+L">J. L. Christiansen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Collins-Hughes%2C+E">E. Collins-Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Coppi%2C+P">P. Coppi</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dwarkadas%2C+V+V">V. V. Dwarkadas</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a> , et al. (66 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1510.01269v1-abstract-short" style="display: inline;"> The Very Energetic Radiation Imaging Telescope Array System (VERITAS) is a ground-based array located at the Fred Lawrence Whipple Observatory in southern Arizona and is one of the world's most sensitive gamma-ray instruments at energies of 85 GeV to $>$30 TeV. VERITAS has a wide scientific reach that includes the study of extragalactic and Galactic objects as well as the search for astrophysical… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.01269v1-abstract-full').style.display = 'inline'; document.getElementById('1510.01269v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1510.01269v1-abstract-full" style="display: none;"> The Very Energetic Radiation Imaging Telescope Array System (VERITAS) is a ground-based array located at the Fred Lawrence Whipple Observatory in southern Arizona and is one of the world's most sensitive gamma-ray instruments at energies of 85 GeV to $>$30 TeV. VERITAS has a wide scientific reach that includes the study of extragalactic and Galactic objects as well as the search for astrophysical signatures of dark matter and the measurement of cosmic rays. In this paper, we will summarize the current status of the VERITAS observatory and present some of the scientific highlights from the last two years, focusing in particular on those results shown at the 2015 ICRC in The Hague, Netherlands. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.01269v1-abstract-full').style.display = 'none'; document.getElementById('1510.01269v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To appear in the Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.04936">arXiv:1509.04936</a> <span> [<a href="https://arxiv.org/pdf/1509.04936">pdf</a>, <a href="https://arxiv.org/ps/1509.04936">ps</a>, <a href="https://arxiv.org/format/1509.04936">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/812/1/65">10.1088/0004-637X/812/1/65 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First NuSTAR Observations of Mrk 501 within a Radio to TeV Multi-Instrument Campaign </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Noda%2C+K">K. Noda</a>, <a href="/search/astro-ph?searchtype=author&query=Boggs%2C+S">S. Boggs</a>, <a href="/search/astro-ph?searchtype=author&query=Chiang%2C+J">J. Chiang</a>, <a href="/search/astro-ph?searchtype=author&query=Christensen%2C+F">F. Christensen</a>, <a href="/search/astro-ph?searchtype=author&query=Craig%2C+W">W. Craig</a>, <a href="/search/astro-ph?searchtype=author&query=Giommi%2C+P+.">P . Giommi</a>, <a href="/search/astro-ph?searchtype=author&query=Hailey%2C+C">C. Hailey</a>, <a href="/search/astro-ph?searchtype=author&query=Harisson%2C+F">F. Harisson</a>, <a href="/search/astro-ph?searchtype=author&query=Madejski%2C+G">G. Madejski</a>, <a href="/search/astro-ph?searchtype=author&query=Nalewajko%2C+K">K. Nalewajko</a>, <a href="/search/astro-ph?searchtype=author&query=Perri%2C+M">M. Perri</a>, <a href="/search/astro-ph?searchtype=author&query=Stern%2C+D">D. Stern</a>, <a href="/search/astro-ph?searchtype=author&query=Urry%2C+M">M. Urry</a>, <a href="/search/astro-ph?searchtype=author&query=Verrecchia%2C+F">F. Verrecchia</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+W">W. Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Ahnen%2C+M+L">M. L. Ahnen</a>, <a href="/search/astro-ph?searchtype=author&query=Ansoldi%2C+S">S. Ansoldi</a>, <a href="/search/astro-ph?searchtype=author&query=Antonelli%2C+L+A">L. A. Antonelli</a>, <a href="/search/astro-ph?searchtype=author&query=Antoranz%2C+P">P. Antoranz</a>, <a href="/search/astro-ph?searchtype=author&query=Babic%2C+A">A. Babic</a>, <a href="/search/astro-ph?searchtype=author&query=Banerjee%2C+B">B. Banerjee</a>, <a href="/search/astro-ph?searchtype=author&query=Bangale%2C+P">P. Bangale</a>, <a href="/search/astro-ph?searchtype=author&query=de+Almeida%2C+U+B">U. Barres de Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=Barrio%2C+J+A">J. A. Barrio</a> , et al. (251 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1509.04936v2-abstract-short" style="display: inline;"> We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 1 April and 10 August 2013, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the F… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.04936v2-abstract-full').style.display = 'inline'; document.getElementById('1509.04936v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.04936v2-abstract-full" style="display: none;"> We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 1 April and 10 August 2013, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope (LAT), Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, Mets盲hovi and the F-Gamma consortium. Some of the MAGIC observations were affected by a sand layer from the Saharan desert, and had to be corrected using event-by-event corrections derived with a LIDAR (LIght Detection And Ranging) facility. This is the first time that LIDAR information is used to produce a physics result with Cherenkov Telescope data taken during adverse atmospheric conditions, and hence sets a precedent for the current and future ground-based gamma-ray instruments. The NuSTAR instrument provides unprecedented sensitivity in hard X-rays, showing the source to display a spectral energy distribution between 3 and 79 keV consistent with a log-parabolic spectrum and hard X-ray variability on hour timescales. None (of the four extended NuSTAR observations) shows evidence of the onset of inverse-Compton emission at hard X-ray energies. We apply a single-zone equilibrium synchrotron self-Compton model to five simultaneous broadband spectral energy distributions. We find that the synchrotron self-Compton model can reproduce the observed broadband states through a decrease in the magnetic field strength coinciding with an increase in the luminosity and hardness of the relativistic leptons responsible for the high-energy emission. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.04936v2-abstract-full').style.display = 'none'; document.getElementById('1509.04936v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1506.06246">arXiv:1506.06246</a> <span> [<a href="https://arxiv.org/pdf/1506.06246">pdf</a>, <a href="https://arxiv.org/ps/1506.06246">ps</a>, <a href="https://arxiv.org/format/1506.06246">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/808/2/110">10.1088/0004-637X/808/2/110 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> VERITAS detection of $纬$-ray flaring activity from the BL Lac object 1ES 1727+502 during bright moonlight observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Biteau%2C+J">J. Biteau</a>, <a href="/search/astro-ph?searchtype=author&query=Bouvier%2C+A">A. Bouvier</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Fortin%2C+P">P. Fortin</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a> , et al. (58 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1506.06246v1-abstract-short" style="display: inline;"> During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHE, $E>100$ GeV) are constrained since the photomultiplier tubes (PMTs) in the telescope camera are extremely sensitive to the background moonlight. Observations with the VERITAS telescopes in the standard configuration are performed only with a moon illumination less than 35$\%$ of full moon. Since… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.06246v1-abstract-full').style.display = 'inline'; document.getElementById('1506.06246v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1506.06246v1-abstract-full" style="display: none;"> During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHE, $E>100$ GeV) are constrained since the photomultiplier tubes (PMTs) in the telescope camera are extremely sensitive to the background moonlight. Observations with the VERITAS telescopes in the standard configuration are performed only with a moon illumination less than 35$\%$ of full moon. Since 2012, the VERITAS collaboration has implemented a new observing mode under bright moonlight, by either reducing the voltage applied to the PMTs (reduced-high-voltage configuration, RHV), or by utilizing UV-transparent filters. While these operating modes result in lower sensitivity and increased energy thresholds, the extension of the available observing time is useful for monitoring variable sources such as blazars and sources requiring spectral measurements at the highest energies. In this paper we report the detection of $纬$-ray flaring activity from the BL Lac object 1ES 1727+502 during RHV observations. This detection represents the first evidence of VHE variability from this blazar. The integral flux is $(1.1\pm0.2)\times10^{-11}\mathrm{cm^{-2}s^{-1}}$ above 250 GeV, which is about five times higher than the low-flux state. The detection triggered additional \veritas\ observations during standard dark-time. Multiwavelength observations with the FLWO 48" telescope, and the Swift and Fermi satellites are presented and used to produce the first spectral energy distribution (SED) of this object during $纬$-ray flaring activity. The SED is then fitted with a standard synchrotron-self-Compton model, placing constraints on the properties of the emitting region and of the acceleration mechanism at the origin of the relativistic particle population in the jet. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.06246v1-abstract-full').style.display = 'none'; document.getElementById('1506.06246v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 June, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 3 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1412.4734">arXiv:1412.4734</a> <span> [<a href="https://arxiv.org/pdf/1412.4734">pdf</a>, <a href="https://arxiv.org/format/1412.4734">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/800/1/61">10.1088/0004-637X/800/1/61 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Search for Pulsations from Geminga Above 100 GeV with VERITAS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a> , et al. (59 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1412.4734v1-abstract-short" style="display: inline;"> We present the results of 71.6 hours of observations of the Geminga pulsar (PSR J0633+1746) with the VERITAS very-high-energy gamma-ray telescope array. Data taken with VERITAS between November 2007 and February 2013 were phase-folded using a Geminga pulsar timing solution derived from data recorded by the XMM-\emph{Newton} and \emph{Fermi}-LAT space telescopes. No significant pulsed emission abov… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.4734v1-abstract-full').style.display = 'inline'; document.getElementById('1412.4734v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1412.4734v1-abstract-full" style="display: none;"> We present the results of 71.6 hours of observations of the Geminga pulsar (PSR J0633+1746) with the VERITAS very-high-energy gamma-ray telescope array. Data taken with VERITAS between November 2007 and February 2013 were phase-folded using a Geminga pulsar timing solution derived from data recorded by the XMM-\emph{Newton} and \emph{Fermi}-LAT space telescopes. No significant pulsed emission above 100 GeV is observed, and we report upper limits at the 95% confidence level on the integral flux above 135 GeV (spectral analysis threshold) of 4.0$\times10^{-13}$ s$^{-1}$ cm$^{-2}$ and 1.7$\times10^{-13}$ s$^{-1}$ cm$^{-2}$ for the two principal peaks in the emission profile. These upper limits, placed in context with phase-resolved spectral energy distributions determined from five years of data from the \emph{Fermi}-LAT, constrain possible hardening of the Geminga pulsar emission spectra above $\sim$50 GeV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.4734v1-abstract-full').style.display = 'none'; document.getElementById('1412.4734v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 December, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 2 figures, 2 tables. Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1412.3576">arXiv:1412.3576</a> <span> [<a href="https://arxiv.org/pdf/1412.3576">pdf</a>, <a href="https://arxiv.org/ps/1412.3576">ps</a>, <a href="https://arxiv.org/format/1412.3576">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201424811">10.1051/0004-6361/201424811 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unprecedented study of the broadband emission of Mrk 421 during flaring activity in March 2010 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+MAGIC+Collaboration"> The MAGIC Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Aleksi%C4%87%2C+J">J. Aleksi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Ansoldi%2C+S">S. Ansoldi</a>, <a href="/search/astro-ph?searchtype=author&query=Antonelli%2C+L+A">L. A. Antonelli</a>, <a href="/search/astro-ph?searchtype=author&query=Antoranz%2C+P">P. Antoranz</a>, <a href="/search/astro-ph?searchtype=author&query=Babic%2C+A">A. Babic</a>, <a href="/search/astro-ph?searchtype=author&query=Bangale%2C+P">P. Bangale</a>, <a href="/search/astro-ph?searchtype=author&query=de+Almeida%2C+U+B">U. Barres de Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=Barrio%2C+J+A">J. A. Barrio</a>, <a href="/search/astro-ph?searchtype=author&query=Gonz%C3%A1lez%2C+J+B">J. Becerra Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Bednarek%2C+W">W. Bednarek</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Biasuzzi%2C+B">B. Biasuzzi</a>, <a href="/search/astro-ph?searchtype=author&query=Biland%2C+A">A. Biland</a>, <a href="/search/astro-ph?searchtype=author&query=Blanch%2C+O">O. Blanch</a>, <a href="/search/astro-ph?searchtype=author&query=Boller%2C+A">A. Boller</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnefoy%2C+S">S. Bonnefoy</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">G. Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Borracci%2C+F">F. Borracci</a>, <a href="/search/astro-ph?searchtype=author&query=Bretz%2C+T">T. Bretz</a>, <a href="/search/astro-ph?searchtype=author&query=Carmona%2C+E">E. Carmona</a>, <a href="/search/astro-ph?searchtype=author&query=Carosi%2C+A">A. Carosi</a>, <a href="/search/astro-ph?searchtype=author&query=Colin%2C+P">P. Colin</a>, <a href="/search/astro-ph?searchtype=author&query=Colombo%2C+E">E. Colombo</a>, <a href="/search/astro-ph?searchtype=author&query=Contreras%2C+J+L">J. L. Contreras</a> , et al. (230 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1412.3576v2-abstract-short" style="display: inline;"> A flare from the TeV blazar Mrk 421, occurring in March 2010, was observed for 13 consecutive days from radio to very high energy (VHE, E > 100 GeV) gamma-rays with MAGIC, VERITAS, Whipple, FermiLAT, MAXI, RXTE, Swift, GASP-WEBT, and several optical and radio telescopes. We model the day-scale SEDs with one-zone and two-zone synchrotron self-Compton (SSC) models, investigate the physical parameter… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.3576v2-abstract-full').style.display = 'inline'; document.getElementById('1412.3576v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1412.3576v2-abstract-full" style="display: none;"> A flare from the TeV blazar Mrk 421, occurring in March 2010, was observed for 13 consecutive days from radio to very high energy (VHE, E > 100 GeV) gamma-rays with MAGIC, VERITAS, Whipple, FermiLAT, MAXI, RXTE, Swift, GASP-WEBT, and several optical and radio telescopes. We model the day-scale SEDs with one-zone and two-zone synchrotron self-Compton (SSC) models, investigate the physical parameters, and evaluate whether the observed broadband SED variability can be associated to variations in the relativistic particle population. Flux variability was remarkable in the X-ray and VHE bands while it was minor or not significant in the other bands. The one-zone SSC model can describe reasonably well the SED of each day for the 13 consecutive days. This flaring activity is also very well described by a two-zone SSC model, where one zone is responsible for the quiescent emission while the other smaller zone, which is spatially separated from the first one, contributes to the daily-variable emission occurring in X-rays and VHE gamma-rays. Both the one-zone SSC and the two-zone SSC models can describe the daily SEDs via the variation of only four or five model parameters, under the hypothesis that the variability is associated mostly to the underlying particle population. This shows that the particle acceleration and cooling mechanism producing the radiating particles could be the main one responsible for the broadband SED variations during the flaring episodes in blazars. The two-zone SSC model provides a better agreement to the observed SED at the narrow peaks of the low- and high-energy bumps during the highest activity, although the reported one-zone SSC model could be further improved by the variation of the parameters related to the emitting region itself ($未$, $B$ and $R$), in addition to the parameters related to the particle population. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.3576v2-abstract-full').style.display = 'none'; document.getElementById('1412.3576v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 June, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 December, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Published in A&A, 30 pages, 15 figures, 6 tables. Online-data: multi-wavelength light curves (data in Fig. 1) and broadband spectral energy distributions (the data in Figs. 6, and B1-B4) are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/578/A22. Corresponding authors: David Paneque (dpaneque@mpp.mpg.de), Shangyu Sun (sysun@mpp.mpg.de), Hajime Takami (takami@post.kek.jp)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 578, A22 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1412.1031">arXiv:1412.1031</a> <span> [<a href="https://arxiv.org/pdf/1412.1031">pdf</a>, <a href="https://arxiv.org/ps/1412.1031">ps</a>, <a href="https://arxiv.org/format/1412.1031">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/797/2/89">10.1088/0004-637X/797/2/89 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigating Broadband Variability of the TeV Blazar 1ES 1959+650 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Arlen%2C+T">T. Arlen</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Bouvier%2C+A">A. Bouvier</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Collins-Hughes%2C+E">E. Collins-Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a> , et al. (70 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1412.1031v1-abstract-short" style="display: inline;"> We summarize broadband observations of the TeV-emitting blazar 1ES 1959+650, including optical R-band observations by the robotic telescopes Super-LOTIS and iTelescope, UV observations by Swift UVOT, X-ray observations by the Swift X-ray Telescope (XRT), high-energy gamma-ray observations with the Fermi Large Area Telescope (LAT) and very-high-energy (VHE) gamma-ray observations by VERITAS above 3… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.1031v1-abstract-full').style.display = 'inline'; document.getElementById('1412.1031v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1412.1031v1-abstract-full" style="display: none;"> We summarize broadband observations of the TeV-emitting blazar 1ES 1959+650, including optical R-band observations by the robotic telescopes Super-LOTIS and iTelescope, UV observations by Swift UVOT, X-ray observations by the Swift X-ray Telescope (XRT), high-energy gamma-ray observations with the Fermi Large Area Telescope (LAT) and very-high-energy (VHE) gamma-ray observations by VERITAS above 315 GeV, all taken between 17 April 2012 and 1 June 2012 (MJD 56034 and 56079). The contemporaneous variability of the broadband spectral energy distribution is explored in the context of a simple synchrotron self Compton (SSC) model. In the SSC emission scenario, we find that the parameters required to represent the high state are significantly different than those in the low state. Motivated by possible evidence of gas in the vicinity of the blazar, we also investigate a reflected-emission model to describe the observed variability pattern. This model assumes that the non-thermal emission from the jet is reflected by a nearby cloud of gas, allowing the reflected emission to re-enter the blob and produce an elevated gamma-ray state with no simultaneous elevated synchrotron flux. The model applied here, although not required to explain the observed variability pattern, represents one possible scenario which can describe the observations. As applied to an elevated VHE state of 66% of the Crab Nebula flux, observed on a single night during the observation period, the reflected-emission scenario does not support a purely leptonic non-thermal emission mechanism. The reflected emission model does, however, predict a reflected photon field with sufficient energy to enable elevated gamma-ray emission via pion production with protons of energies between 10 and 100 TeV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.1031v1-abstract-full').style.display = 'none'; document.getElementById('1412.1031v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 December, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1411.1439">arXiv:1411.1439</a> <span> [<a href="https://arxiv.org/pdf/1411.1439">pdf</a>, <a href="https://arxiv.org/format/1411.1439">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/799/1/7">10.1088/0004-637X/799/1/7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> VERITAS Observations of the BL Lac Object PG 1553+113 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Archer%2C+A">A. Archer</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Behera%2C+B">B. Behera</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a> , et al. (62 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1411.1439v1-abstract-short" style="display: inline;"> We present results from VERITAS observations of the BL Lac object PG 1553+113 spanning the years 2010, 2011, and 2012. The time-averaged spectrum, measured between 160 and 560\,GeV, is well described by a power law with a spectral index of $4.33 \pm 0.09$. The time-averaged integral flux above $200\,$GeV measured for this period was… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.1439v1-abstract-full').style.display = 'inline'; document.getElementById('1411.1439v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1411.1439v1-abstract-full" style="display: none;"> We present results from VERITAS observations of the BL Lac object PG 1553+113 spanning the years 2010, 2011, and 2012. The time-averaged spectrum, measured between 160 and 560\,GeV, is well described by a power law with a spectral index of $4.33 \pm 0.09$. The time-averaged integral flux above $200\,$GeV measured for this period was $(1.69 \pm 0.06) \times 10^{-11} \, \mathrm{ph} \, \mathrm{cm}^{-2} \, \mathrm{s}^{-1}$, corresponding to 6.9\% of the Crab Nebula flux. We also present the combined $纬$-ray spectrum from the Fermi Large Area Telescope and VERITAS covering an energy range from 100~MeV to 560~GeV. The data are well fit by a power law with an exponential cutoff at $\rm {101.9 \pm 3.2 \, \mathrm{GeV}} $. The origin of the cutoff could be intrinsic to PG~1553+113 or be due to the $纬$-ray opacity of our universe through pair production off the extragalactic background light (EBL). Given lower limits to the redshift of $\rm z \negthinspace > \negthinspace 0.395$ based on optical/UV observations of PG~1553+113, the cutoff would be dominated by EBL absorption. Conversely, the small statistical uncertainties of the VERITAS energy spectrum have allowed us to provide a robust upper limit on the redshift of PG 1553+113 of $z \negthinspace \leq \negthinspace 0.62$. A strongly-elevated mean flux of $(2.50 \pm 0.14) \times 10^{-11} \, \mathrm{ph} \, \mathrm{cm}^{-2} \, \mathrm{s}^{-1}$ (10.3\% of the Crab Nebula flux) was observed during 2012, with the daily flux reaching as high as $(4.44 \pm 0.71) \times 10^{-11} \, \mathrm{ph} \, \mathrm{cm}^{-2} \, \mathrm{s}^{-1}$ (18.3\% of the Crab Nebula flux) on MJD 56048. The light curve measured during the 2012 observing season is marginally inconsistent with a steady flux, giving a $蠂^2$ probability for a steady flux of 0.03\%. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.1439v1-abstract-full').style.display = 'none'; document.getElementById('1411.1439v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 November, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">in press in ApJ, 2014</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1410.7144">arXiv:1410.7144</a> <span> [<a href="https://arxiv.org/pdf/1410.7144">pdf</a>, <a href="https://arxiv.org/ps/1410.7144">ps</a>, <a href="https://arxiv.org/format/1410.7144">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stu2251">10.1093/mnras/stu2251 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The most powerful flaring activity from the NLSy1 PMN J0948+0022 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=D%27Ammando%2C+F">F. D'Ammando</a>, <a href="/search/astro-ph?searchtype=author&query=Orienti%2C+M">M. Orienti</a>, <a href="/search/astro-ph?searchtype=author&query=Finke%2C+J">J. Finke</a>, <a href="/search/astro-ph?searchtype=author&query=Raiteri%2C+C+M">C. M. Raiteri</a>, <a href="/search/astro-ph?searchtype=author&query=Hovatta%2C+T">T. Hovatta</a>, <a href="/search/astro-ph?searchtype=author&query=Larsson%2C+J">J. Larsson</a>, <a href="/search/astro-ph?searchtype=author&query=Max-Moerbeck%2C+W">W. Max-Moerbeck</a>, <a href="/search/astro-ph?searchtype=author&query=Perkins%2C+J">J. Perkins</a>, <a href="/search/astro-ph?searchtype=author&query=Readhead%2C+A+C+S">A. C. S. Readhead</a>, <a href="/search/astro-ph?searchtype=author&query=Richards%2C+J+L">J. L. Richards</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V. Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a> , et al. (51 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1410.7144v1-abstract-short" style="display: inline;"> We report on multifrequency observations performed during 2012 December-2013 August of the first narrow-line Seyfert 1 galaxy detected in gamma rays, PMN J0948+0022 ($z$ = 0.5846). A gamma-ray flare was observed by the Large Area Telescope on board Fermi during 2012 December-2013 January, reaching a daily peak flux in the 0.1-100 GeV energy range of (155 $\pm$ 31) $\times$10$^{-8}$ ph cm$^{-2}$ s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.7144v1-abstract-full').style.display = 'inline'; document.getElementById('1410.7144v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1410.7144v1-abstract-full" style="display: none;"> We report on multifrequency observations performed during 2012 December-2013 August of the first narrow-line Seyfert 1 galaxy detected in gamma rays, PMN J0948+0022 ($z$ = 0.5846). A gamma-ray flare was observed by the Large Area Telescope on board Fermi during 2012 December-2013 January, reaching a daily peak flux in the 0.1-100 GeV energy range of (155 $\pm$ 31) $\times$10$^{-8}$ ph cm$^{-2}$ s$^{-1}$ on 2013 January 1, corresponding to an apparent isotropic luminosity of about 1.5$\times$10$^{48}$ erg s$^{-1}$. The gamma-ray flaring period triggered Swift and VERITAS observations in addition to radio and optical monitoring by OVRO, MOJAVE, and CRTS. A strong flare was observed in optical, UV, and X-rays on 2012 December 30, quasi-simultaneously to the gamma-ray flare, reaching a record flux for this source from optical to gamma rays. VERITAS observations at very high energy (E > 100 GeV) during 2013 January 6-17 resulted in an upper limit of F (> 0.2 TeV) < 4.0$\times$10$^{-12}$ ph cm$^{-2}$ s$^{-1}$. We compared the spectral energy distribution (SED) of the flaring state in 2013 January with that of an intermediate state observed in 2011. The two SEDs, modelled as synchrotron emission and an external Compton scattering of seed photons from a dust torus, can be modelled by changing both the electron distribution parameters and the magnetic field. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.7144v1-abstract-full').style.display = 'none'; document.getElementById('1410.7144v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 October, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 5 Figures, 5 Tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1410.6391">arXiv:1410.6391</a> <span> [<a href="https://arxiv.org/pdf/1410.6391">pdf</a>, <a href="https://arxiv.org/ps/1410.6391">ps</a>, <a href="https://arxiv.org/format/1410.6391">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201322906">10.1051/0004-6361/201322906 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multiwavelength observations of Mrk 501 in 2008 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=MAGIC+Collaboration"> MAGIC Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Aleksi%C4%87%2C+J">J. Aleksi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Ansoldi%2C+S">S. Ansoldi</a>, <a href="/search/astro-ph?searchtype=author&query=Antonelli%2C+L+A">L. A. Antonelli</a>, <a href="/search/astro-ph?searchtype=author&query=Antoranz%2C+P">P. Antoranz</a>, <a href="/search/astro-ph?searchtype=author&query=Babic%2C+A">A. Babic</a>, <a href="/search/astro-ph?searchtype=author&query=Bangale%2C+P">P. Bangale</a>, <a href="/search/astro-ph?searchtype=author&query=de+Almeida%2C+U+B">U. Barres de Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=Barrio%2C+J+A">J. A. Barrio</a>, <a href="/search/astro-ph?searchtype=author&query=Gonz%C3%A1lez%2C+J+B">J. Becerra Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Bednarek%2C+W">W. Bednarek</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Biland%2C+A">A. Biland</a>, <a href="/search/astro-ph?searchtype=author&query=Blanch%2C+O">O. Blanch</a>, <a href="/search/astro-ph?searchtype=author&query=Bock%2C+R+K">R. K. Bock</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnefoy%2C+S">S. Bonnefoy</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">G. Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Borracci%2C+F">F. Borracci</a>, <a href="/search/astro-ph?searchtype=author&query=Bretz%2C+T">T. Bretz</a>, <a href="/search/astro-ph?searchtype=author&query=Carmona%2C+E">E. Carmona</a>, <a href="/search/astro-ph?searchtype=author&query=Carosi%2C+A">A. Carosi</a>, <a href="/search/astro-ph?searchtype=author&query=Fidalgo%2C+D+C">D. Carreto Fidalgo</a>, <a href="/search/astro-ph?searchtype=author&query=Colin%2C+P">P. Colin</a>, <a href="/search/astro-ph?searchtype=author&query=Colombo%2C+E">E. Colombo</a> , et al. (237 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1410.6391v1-abstract-short" style="display: inline;"> Mrk 501 is one of the brightest blazars at TeV energies and has been extensively studied since its first VHE detection in 1996. Our goal is to characterize in detail the source gamma-ray emission, together with the radio-to-X-ray emission, during the non-flaring (low) activity, which is less often studied than the occasional flaring (high) activity. We organized a multiwavelength (MW) campaign on… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.6391v1-abstract-full').style.display = 'inline'; document.getElementById('1410.6391v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1410.6391v1-abstract-full" style="display: none;"> Mrk 501 is one of the brightest blazars at TeV energies and has been extensively studied since its first VHE detection in 1996. Our goal is to characterize in detail the source gamma-ray emission, together with the radio-to-X-ray emission, during the non-flaring (low) activity, which is less often studied than the occasional flaring (high) activity. We organized a multiwavelength (MW) campaign on Mrk 501 between March and May 2008. This multi-instrument effort included the most sensitive VHE gamma-ray instruments in the northern hemisphere, namely the imaging atmospheric Cherenkov telescopes MAGIC and VERITAS, as well as Swift, RXTE, the F-GAMMA, GASP-WEBT, and other collaborations and instruments. Mrk 501 was found to be in a low state of activity during the campaign, with a VHE flux in the range of 10%-20% of the Crab nebula flux. Nevertheless, significant flux variations were detected with various instruments, with a trend of increasing variability with energy. The broadband spectral energy distribution during the two different emission states of the campaign can be adequately described within the homogeneous one-zone synchrotron self-Compton model, with the (slightly) higher state described by an increase in the electron number density. This agrees with previous studies of the broadband emission of this source during flaring and non-flaring states. We report for the first time a tentative X-ray-to-VHE correlation during a low VHE activity. Although marginally significant, this positive correlation between X-ray and VHE, which has been reported many times during flaring activity, suggests that the mechanisms that dominate the X-ray/VHE emission during non-flaring-activity are not substantially different from those that are responsible for the emission during flaring activity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.6391v1-abstract-full').style.display = 'none'; document.getElementById('1410.6391v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 October, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> MPP-2014-381 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1410.5367">arXiv:1410.5367</a> <span> [<a href="https://arxiv.org/pdf/1410.5367">pdf</a>, <a href="https://arxiv.org/format/1410.5367">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/2041-8205/795/1/L3">10.1088/2041-8205/795/1/L3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Constraints on Very High Energy Emission from GRB 130427A </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Barnacka%2C+A">A. Barnacka</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Biteau%2C+J">J. Biteau</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connaughton%2C+V">V. Connaughton</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dickinson%2C+H+J">H. J. Dickinson</a>, <a href="/search/astro-ph?searchtype=author&query=Eisch%2C+J+D">J. D. Eisch</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Fortin%2C+P">P. Fortin</a> , et al. (67 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1410.5367v1-abstract-short" style="display: inline;"> Prompt emission from the very fluent and nearby (z=0.34) gamma-ray burst GRB 130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it is exceptional due to the extremely long-lived high-energy (100 MeV to 100 GeV) gamma-ray emission, which was detected by the Large Area Telescope o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.5367v1-abstract-full').style.display = 'inline'; document.getElementById('1410.5367v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1410.5367v1-abstract-full" style="display: none;"> Prompt emission from the very fluent and nearby (z=0.34) gamma-ray burst GRB 130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it is exceptional due to the extremely long-lived high-energy (100 MeV to 100 GeV) gamma-ray emission, which was detected by the Large Area Telescope on the Fermi Gamma-ray Space Telescope for ~70 ks after the initial burst. The persistent, hard-spectrum, high-energy emission suggests that the highest-energy gamma rays may have been produced via synchrotron self-Compton processes though there is also evidence that the high-energy emission may instead be an extension of the synchrotron spectrum. VERITAS, a ground-based imaging atmospheric Cherenkov telescope array, began follow-up observations of GRB 130427A ~71 ks (~20 hr) after the onset of the burst. The GRB was not detected with VERITAS; however, the high elevation of the observations, coupled with the low redshift of the GRB, make VERITAS a very sensitive probe of the emission from GRB 130427A for E > 100 GeV. The non-detection and consequent upper limit derived place constraints on the synchrotron self-Compton model of high-energy gamma-ray emission from this burst. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.5367v1-abstract-full').style.display = 'none'; document.getElementById('1410.5367v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 October, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages, 4 figures, 1 table</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophysical Journal Letters, 795, 2014, L3 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1404.7185">arXiv:1404.7185</a> <span> [<a href="https://arxiv.org/pdf/1404.7185">pdf</a>, <a href="https://arxiv.org/ps/1404.7185">ps</a>, <a href="https://arxiv.org/format/1404.7185">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/787/2/166">10.1088/0004-637X/787/2/166 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigating the TeV Morphology of MGRO J1908+06 with VERITAS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Behera%2C+B">B. Behera</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Collins-Hughes%2C+E">E. Collins-Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Dwarkadas%2C+V+V">V. V. Dwarkadas</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a> , et al. (63 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1404.7185v1-abstract-short" style="display: inline;"> We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy (VHE) gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14 sigma) and measure a photon index of 2.20 +/- 0.10_… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.7185v1-abstract-full').style.display = 'inline'; document.getElementById('1404.7185v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1404.7185v1-abstract-full" style="display: none;"> We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy (VHE) gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14 sigma) and measure a photon index of 2.20 +/- 0.10_stat +/- 0.20_sys. The TeV emission is extended, covering the region near PSR J1907+0602 and also extending towards SNR G40.5--0.5. When fitted with a 2-dimensional Gaussian, the intrinsic extension has a standard deviation of sigma_src = 0.44 +/- 0.02 degrees. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5--0.5, 0.33 degrees away. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.7185v1-abstract-full').style.display = 'none'; document.getElementById('1404.7185v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 April, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To appear in ApJ, 8 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1403.4308">arXiv:1403.4308</a> <span> [<a href="https://arxiv.org/pdf/1403.4308">pdf</a>, <a href="https://arxiv.org/ps/1403.4308">ps</a>, <a href="https://arxiv.org/format/1403.4308">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/2041-8205/785/1/L16">10.1088/2041-8205/785/1/L16 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Deep Broadband Observations of the Distant Gamma-ray Blazar PKS 1424+240 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Behera%2C+B">B. Behera</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Biteau%2C+J">J. Biteau</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fleischhack%2C+H">H. Fleischhack</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a> , et al. (127 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1403.4308v1-abstract-short" style="display: inline;"> We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of $z\ge0.6035$, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.4308v1-abstract-full').style.display = 'inline'; document.getElementById('1403.4308v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1403.4308v1-abstract-full" style="display: none;"> We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of $z\ge0.6035$, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hours of VERITAS observations from three years, a multiwavelength light curve and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1$\pm0.3$)$\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02$\pm0.08$)$\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV. The measured differential very high energy (VHE; $E\ge100$ GeV) spectral indices are $螕=$3.8$\pm$0.3, 4.3$\pm$0.6 and 4.5$\pm$0.2 in 2009, 2011 and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than $蟿=2$, where it is postulated that any variability would be small and occur on longer than year timescales if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.4308v1-abstract-full').style.display = 'none'; document.getElementById('1403.4308v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 March, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">ApJL accepted March 17, 2014</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1401.2828">arXiv:1401.2828</a> <span> [<a href="https://arxiv.org/pdf/1401.2828">pdf</a>, <a href="https://arxiv.org/format/1401.2828">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/783/1/16">10.1088/0004-637X/783/1/16 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observations of the unidentified gamma-ray source TeV J2032+4130 by VERITAS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=VERITAS+Collaboration"> VERITAS Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Behera%2C+B">B. Behera</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Cardenzana%2C+J+V">J. V Cardenzana</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Duke%2C+C">C. Duke</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortin%2C+P">P. Fortin</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a> , et al. (55 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1401.2828v2-abstract-short" style="display: inline;"> TeV J2032+4130 was the first unidentified source discovered at very high energies (VHE; E $>$ 100 GeV), with no obvious counterpart in any other wavelength. It is also the first extended source to be observed in VHE gamma rays. Following its discovery, intensive observational campaigns have been carried out in all wavelengths in order to understand the nature of the object, which have met with lim… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.2828v2-abstract-full').style.display = 'inline'; document.getElementById('1401.2828v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1401.2828v2-abstract-full" style="display: none;"> TeV J2032+4130 was the first unidentified source discovered at very high energies (VHE; E $>$ 100 GeV), with no obvious counterpart in any other wavelength. It is also the first extended source to be observed in VHE gamma rays. Following its discovery, intensive observational campaigns have been carried out in all wavelengths in order to understand the nature of the object, which have met with limited success. We report here on a deep observation of TeV J2032+4130, based on 48.2 hours of data taken from 2009 to 2012 by the VERITAS (Very Energetic Radiation Imaging Telescope Array System) experiment. The source is detected at 8.7 standard deviations ($蟽$) and is found to be extended and asymmetric with a width of 9.5$^{\prime}$$\pm$1.2$^{\prime}$ along the major axis and 4.0$^{\prime}$$\pm$0.5$^{\prime}$ along the minor axis. The spectrum is well described by a differential power law with an index of 2.10 $\pm$ 0.14$_{stat}$ $\pm$ 0.21$_{sys}$ and a normalization of (9.5 $\pm$ 1.6$_{stat}$ $\pm$ 2.2$_{sys}$) $\times$ 10$^{-13}$TeV$^{-1}$ cm$^{-2}$ s$^{-1}$ at 1 TeV. We interpret these results in the context of multiwavelength scenarios which particularly favor the pulsar wind nebula (PWN) interpretation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.2828v2-abstract-full').style.display = 'none'; document.getElementById('1401.2828v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 January, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 January, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2014. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1312.6592">arXiv:1312.6592</a> <span> [<a href="https://arxiv.org/pdf/1312.6592">pdf</a>, <a href="https://arxiv.org/ps/1312.6592">ps</a>, <a href="https://arxiv.org/format/1312.6592">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/782/1/13">10.1088/0004-637X/782/1/13 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Three-Year Multi-Wavelength Study of the Very High Energy Gamma-ray Blazar 1ES 0229+200 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Arlen%2C+T">T. Arlen</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Behera%2C+B">B. Behera</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Bouvier%2C+A">A. Bouvier</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Duke%2C+C">C. Duke</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a> , et al. (61 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1312.6592v1-abstract-short" style="display: inline;"> The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Gamma ~ 2.5), very-high-energy-emitting (E > 100 GeV) gamma-ray blazar. Very-high-energy measurements of this active galactic nucleus have been used to place constraints on the intensity of the extragalactic background light and the intergalactic magnetic field. A multi-wavelength study o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.6592v1-abstract-full').style.display = 'inline'; document.getElementById('1312.6592v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1312.6592v1-abstract-full" style="display: none;"> The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Gamma ~ 2.5), very-high-energy-emitting (E > 100 GeV) gamma-ray blazar. Very-high-energy measurements of this active galactic nucleus have been used to place constraints on the intensity of the extragalactic background light and the intergalactic magnetic field. A multi-wavelength study of this object centered around very-high-energy observations by VERITAS is presented. This study obtained, over a period of three years, an 11.7 standard deviation detection and an average integral flux F(E>300 GeV) = (23.3 +- 2.8_stat +- 5.8_sys) x 10^-9 photons m^-2 s^-1, or 1.7% of the Crab Nebula's flux (assuming the Crab Nebula spectrum measured by H.E.S.S). Supporting observations from Swift and RXTE are analyzed. The Swift observations are combined with previously published Fermi observations and the very-high-energy measurements to produce an overall spectral energy distribution which is then modeled assuming one-zone synchrotron-self-Compton emission. The chi^2 probability of the TeV flux being constant is 1.6%. This, when considered in combination with measured variability in the X-ray band, and the demonstrated variability of many TeV blazars, suggests that the use of blazars such as 1ES 0229+200 for intergalactic magnetic field studies may not be straightforward and challenges models that attribute hard TeV spectra to secondary gamma-ray production along the line of sight. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.6592v1-abstract-full').style.display = 'none'; document.getElementById('1312.6592v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 December, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1311.6083">arXiv:1311.6083</a> <span> [<a href="https://arxiv.org/pdf/1311.6083">pdf</a>, <a href="https://arxiv.org/format/1311.6083">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/780/2/168">10.1088/0004-637X/780/2/168 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Long-term TeV and X-ray Observations of the Gamma-ray Binary HESS J0632+057 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=VERITAS+Collaboration"> VERITAS Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Aliu%2C+E">E. Aliu</a>, <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Behera%2C+B">B. Behera</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Bouvier%2C+A">A. Bouvier</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Duke%2C+C">C. Duke</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a> , et al. (277 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1311.6083v1-abstract-short" style="display: inline;"> HESS J0632+057 is the only gamma-ray binary known so far whose position in the sky allows observations with ground-based observatories both in the northern and southern hemispheres. Here we report on long-term observations of HESS J0632+057 conducted with the VERITAS and H.E.S.S. Cherenkov Telescopes and the X-ray Satellite Swift, spanning a time range from 2004 to 2012 and covering most of the sy… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.6083v1-abstract-full').style.display = 'inline'; document.getElementById('1311.6083v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1311.6083v1-abstract-full" style="display: none;"> HESS J0632+057 is the only gamma-ray binary known so far whose position in the sky allows observations with ground-based observatories both in the northern and southern hemispheres. Here we report on long-term observations of HESS J0632+057 conducted with the VERITAS and H.E.S.S. Cherenkov Telescopes and the X-ray Satellite Swift, spanning a time range from 2004 to 2012 and covering most of the system's orbit. The VHE emission is found to be variable, and is correlated with that at X-ray energies. An orbital period of $315 ^{+6}_{-4}$ days is derived from the X-ray data set, which is compatible with previous results, $P = (321 \pm 5$) days. The VHE light curve shows a distinct maximum at orbital phases close to 0.3, or about 100 days after periastron passage, which coincides with the periodic enhancement of the X-ray emission. Furthermore, the analysis of the TeV data shows for the first time a statistically significant ($> 6.5 蟽$) detection at orbital phases 0.6--0.9. The obtained gamma-ray and X-ray light curves and the correlation of the source emission at these two energy bands are discussed in the context of the recent ephemeris obtained for the system. Our results are compared to those reported for other gamma-ray binaries. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.6083v1-abstract-full').style.display = 'none'; document.getElementById('1311.6083v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 November, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">35 pages, 8 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1311.0919">arXiv:1311.0919</a> <span> [<a href="https://arxiv.org/pdf/1311.0919">pdf</a>, <a href="https://arxiv.org/format/1311.0919">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/779/2/150">10.1088/0004-637X/779/2/150 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> VERITAS Observations of the Microquasar Cygnus X-3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Archambault%2C+S">S. Archambault</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">K. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Bouvier%2C+A">A. Bouvier</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Byrum%2C+K">K. Byrum</a>, <a href="/search/astro-ph?searchtype=author&query=Cerruti%2C+M">M. Cerruti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Duke%2C+C">C. Duke</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+Q">Q. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a>, <a href="/search/astro-ph?searchtype=author&query=Furniss%2C+A">A. Furniss</a>, <a href="/search/astro-ph?searchtype=author&query=Galante%2C+N">N. Galante</a>, <a href="/search/astro-ph?searchtype=author&query=Gillanders%2C+G+H">G. H. Gillanders</a> , et al. (54 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1311.0919v1-abstract-short" style="display: inline;"> We report results from TeV gamma-ray observations of the microquasar Cygnus X-3. The observations were made with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) over a time period from 2007 June 11 to 2011 November 28. VERITAS is most sensitive to gamma rays at energies between 85 GeV to 30 TeV. The effective exposure time amounts to a total of about 44 hours, with the observ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.0919v1-abstract-full').style.display = 'inline'; document.getElementById('1311.0919v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1311.0919v1-abstract-full" style="display: none;"> We report results from TeV gamma-ray observations of the microquasar Cygnus X-3. The observations were made with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) over a time period from 2007 June 11 to 2011 November 28. VERITAS is most sensitive to gamma rays at energies between 85 GeV to 30 TeV. The effective exposure time amounts to a total of about 44 hours, with the observations covering six distinct radio/X-ray states of the object. No significant TeV gamma-ray emission was detected in any of the states, nor with all observations combined. The lack of a positive signal, especially in the states where GeV gamma rays were detected, places constraints on TeV gamma-ray production in Cygnus X-3. We discuss the implications of the results. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.0919v1-abstract-full').style.display = 'none'; document.getElementById('1311.0919v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 November, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 4 figures, 3 tables, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1310.8150">arXiv:1310.8150</a> <span> [<a href="https://arxiv.org/pdf/1310.8150">pdf</a>, <a href="https://arxiv.org/ps/1310.8150">ps</a>, <a href="https://arxiv.org/format/1310.8150">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.astropartphys.2013.10.004">10.1016/j.astropartphys.2013.10.004 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of Markarian 421 in TeV gamma rays over a 14-year time span </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Arlen%2C+T">T. Arlen</a>, <a href="/search/astro-ph?searchtype=author&query=Aune%2C+T">T. Aune</a>, <a href="/search/astro-ph?searchtype=author&query=Benbow%2C+W">W. Benbow</a>, <a href="/search/astro-ph?searchtype=author&query=Bird%2C+R">R. Bird</a>, <a href="/search/astro-ph?searchtype=author&query=Bouvier%2C+A">A. Bouvier</a>, <a href="/search/astro-ph?searchtype=author&query=Bradbury%2C+S+M">S. M. Bradbury</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+J+H">J. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Bugaev%2C+V">V. Bugaev</a>, <a href="/search/astro-ph?searchtype=author&query=Perez%2C+I+d+l+C">I. de la Calle Perez</a>, <a href="/search/astro-ph?searchtype=author&query=Carter-Lewis%2C+D+A">D. A. Carter-Lewis</a>, <a href="/search/astro-ph?searchtype=author&query=Cesarini%2C+A">A. Cesarini</a>, <a href="/search/astro-ph?searchtype=author&query=Ciupik%2C+L">L. Ciupik</a>, <a href="/search/astro-ph?searchtype=author&query=Collins-Hughes%2C+E">E. Collins-Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Connolly%2C+M+P">M. P. Connolly</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+W">W. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Duke%2C+C">C. Duke</a>, <a href="/search/astro-ph?searchtype=author&query=Dumm%2C+J">J. Dumm</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A">A. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Federici%2C+S">S. Federici</a>, <a href="/search/astro-ph?searchtype=author&query=Fegan%2C+D+J">D. J. Fegan</a>, <a href="/search/astro-ph?searchtype=author&query=Fegan%2C+S+J">S. J. Fegan</a>, <a href="/search/astro-ph?searchtype=author&query=Finley%2C+J+P">J. P. Finley</a>, <a href="/search/astro-ph?searchtype=author&query=Finnegan%2C+G">G. Finnegan</a>, <a href="/search/astro-ph?searchtype=author&query=Fortson%2C+L">L. Fortson</a> , et al. (51 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1310.8150v1-abstract-short" style="display: inline;"> The variability of the blazar Markarian 421 in TeV gamma rays over a 14-year time period has been explored with the Whipple 10 m telescope. It is shown that the dynamic range of its flux variations is large and similar to that in X-rays. A correlation between the X-ray and TeV energy bands is observed during some bright flares and when the complete data sets are binned on long timescales. The main… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1310.8150v1-abstract-full').style.display = 'inline'; document.getElementById('1310.8150v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1310.8150v1-abstract-full" style="display: none;"> The variability of the blazar Markarian 421 in TeV gamma rays over a 14-year time period has been explored with the Whipple 10 m telescope. It is shown that the dynamic range of its flux variations is large and similar to that in X-rays. A correlation between the X-ray and TeV energy bands is observed during some bright flares and when the complete data sets are binned on long timescales. The main database consists of 878.4 hours of observation with the Whipple telescope, spread over 783 nights. The peak energy response of the telescope was 400 GeV with 20% uncertainty. This is the largest database of any TeV-emitting active galactic nucleus (AGN) and hence was used to explore the variability profile of Markarian 421. The time-averaged flux from Markarian 421 over this period was 0.446$\pm$0.008 Crab flux units. The flux exceeded 10 Crab flux units on three separate occasions. For the 2000-2001 season the average flux reached 1.86 Crab units, while in the 1996-1997 season the average flux was only 0.23 Crab units. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1310.8150v1-abstract-full').style.display = 'none'; document.getElementById('1310.8150v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 October, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">29 pages, 15 figures. Accepted for publication in Astroparticle Physics</span> </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Gillanders%2C+G+H&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Gillanders%2C+G+H&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Gillanders%2C+G+H&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Gillanders%2C+G+H&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> </ul> </nav> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

CINXE.COM

Search | arXiv e-print repository