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<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=Bruel%2C+P&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Bruel%2C+P&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Bruel%2C+P&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </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/2411.07162">arXiv:2411.07162</a> <span> [<a href="https://arxiv.org/pdf/2411.07162">pdf</a>, <a href="https://arxiv.org/format/2411.07162">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"> Search for Extended GeV Sources in the Inner Galactic Plane </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abdollahi%2C+S">S. Abdollahi</a>, <a href="/search/astro-ph?searchtype=author&query=Acero%2C+F">F. Acero</a>, <a href="/search/astro-ph?searchtype=author&query=Acharyya%2C+A">A. Acharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Adelfio%2C+A">A. Adelfio</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Bartolini%2C+C">C. Bartolini</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J+B">J. Becerra Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+D">D. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+C+C">C. C. Cheung</a>, <a href="/search/astro-ph?searchtype=author&query=Cibrario%2C+N">N. Cibrario</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Cozzolongo%2C+G">G. Cozzolongo</a>, <a href="/search/astro-ph?searchtype=author&query=Orestano%2C+P+C">P. Cristarella Orestano</a>, <a href="/search/astro-ph?searchtype=author&query=Cuoco%2C+A">A. Cuoco</a>, <a href="/search/astro-ph?searchtype=author&query=Cutini%2C+S">S. Cutini</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Ammando%2C+F">F. D'Ammando</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="2411.07162v1-abstract-short" style="display: inline;"> The recent detection of extended $纬$-ray emission around middle-aged pulsars is interpreted as inverse-Compton scattering of ambient photons by electron-positron pairs escaping the pulsar wind nebula, which are confined near the system by unclear mechanisms. This emerging population of $纬$-ray sources was first discovered at TeV energies and remains underexplored in the GeV range. To address this,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.07162v1-abstract-full').style.display = 'inline'; document.getElementById('2411.07162v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.07162v1-abstract-full" style="display: none;"> The recent detection of extended $纬$-ray emission around middle-aged pulsars is interpreted as inverse-Compton scattering of ambient photons by electron-positron pairs escaping the pulsar wind nebula, which are confined near the system by unclear mechanisms. This emerging population of $纬$-ray sources was first discovered at TeV energies and remains underexplored in the GeV range. To address this, we conducted a systematic search for extended sources along the Galactic plane using 14 years of Fermi-LAT data above 10 GeV, aiming to identify a number of pulsar halo candidates and extend our view to lower energies. The search covered the inner Galactic plane ($\lvert l\rvert\leq$ 100$^{\circ}$, $\lvert b\rvert\leq$ 1$^{\circ}$) and the positions of known TeV sources and bright pulsars, yielding broader astrophysical interest. We found 40 such sources, forming the Second Fermi Galactic Extended Sources Catalog (2FGES), most with 68% containment radii smaller than 1.0$^{\circ}$ and relatively hard spectra with photon indices below 2.5. We assessed detection robustness using field-specific alternative interstellar emission models and by inspecting significance maps. Noting 13 sources previously known as extended in the 4FGL-DR3 catalog and five dubious sources from complex regions, we report 22 newly detected extended sources above 10 GeV. Of these, 13 coincide with H.E.S.S., HAWC, or LHAASO sources; six coincide with bright pulsars (including four also coincident with TeV sources); six are associated with 4FGL point sources only; and one has no association in the scanned catalogs. Notably, six to eight sources may be related to pulsars as classical pulsar wind nebulae or pulsar halos. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.07162v1-abstract-full').style.display = 'none'; document.getElementById('2411.07162v1-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </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">43 pages, 17 figures, 11 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/2409.04580">arXiv:2409.04580</a> <span> [<a href="https://arxiv.org/pdf/2409.04580">pdf</a>, <a href="https://arxiv.org/format/2409.04580">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"> GRB 221009A: the B.O.A.T Burst that Shines in Gamma Rays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Axelsson%2C+M">M. Axelsson</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Arimoto%2C+M">M. Arimoto</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Baring%2C+M+G">M. G. Baring</a>, <a href="/search/astro-ph?searchtype=author&query=Bartolini%2C+C">C. Bartolini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J+B">J. Becerra Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berenji%2C+B">B. Berenji</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R. Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+C+C">C. C. Cheung</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">G. Chiaro</a>, <a href="/search/astro-ph?searchtype=author&query=Cibrario%2C+N">N. Cibrario</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Cozzolongo%2C+G">G. Cozzolongo</a> , et al. (129 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="2409.04580v1-abstract-short" style="display: inline;"> We present a complete analysis of Fermi Large Area Telescope (LAT) data of GRB 221009A, the brightest Gamma-Ray Burst (GRB) ever detected. The burst emission above 30 MeV detected by the LAT preceded by 1 s the low-energy (< 10 MeV) pulse that triggered the Fermi Gamma-Ray Burst Monitor (GBM), as has been observed in other GRBs. The prompt phase of GRB 221009A lasted a few hundred seconds. It was… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.04580v1-abstract-full').style.display = 'inline'; document.getElementById('2409.04580v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.04580v1-abstract-full" style="display: none;"> We present a complete analysis of Fermi Large Area Telescope (LAT) data of GRB 221009A, the brightest Gamma-Ray Burst (GRB) ever detected. The burst emission above 30 MeV detected by the LAT preceded by 1 s the low-energy (< 10 MeV) pulse that triggered the Fermi Gamma-Ray Burst Monitor (GBM), as has been observed in other GRBs. The prompt phase of GRB 221009A lasted a few hundred seconds. It was so bright that we identify a Bad Time Interval (BTI) of 64 seconds caused by the extremely high flux of hard X-rays and soft gamma rays, during which the event reconstruction efficiency was poor and the dead time fraction quite high. The late-time emission decayed as a power law, but the extrapolation of the late-time emission during the first 450 seconds suggests that the afterglow started during the prompt emission. We also found that high-energy events observed by the LAT are incompatible with synchrotron origin, and, during the prompt emission, are more likely related to an extra component identified as synchrotron self-Compton (SSC). A remarkable 400 GeV photon, detected by the LAT 33 ks after the GBM trigger and directionally consistent with the location of GRB 221009A, is hard to explain as a product of SSC or TeV electromagnetic cascades, and the process responsible for its origin is uncertain. Because of its proximity and energetic nature, GRB 221009A is an extremely rare event. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.04580v1-abstract-full').style.display = 'none'; document.getElementById('2409.04580v1-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </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">60 pages, 38 figures, 9 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/2404.17623">arXiv:2404.17623</a> <span> [<a href="https://arxiv.org/pdf/2404.17623">pdf</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="Astrophysics of Galaxies">astro-ph.GA</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/10.1051/0004-6361/202450497">10.1051/0004-6361/202450497 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Broadband Multi-wavelength Properties of M87 during the 2018 EHT Campaign including a Very High Energy Flaring Episode </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Algaba%2C+J+C">J. C. Algaba</a>, <a href="/search/astro-ph?searchtype=author&query=Balokovic%2C+M">M. Balokovic</a>, <a href="/search/astro-ph?searchtype=author&query=Chandra%2C+S">S. Chandra</a>, <a href="/search/astro-ph?searchtype=author&query=Cheong%2C+W+Y">W. Y. Cheong</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+Y+Z">Y. Z. Cui</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Ammando%2C+F">F. D'Ammando</a>, <a href="/search/astro-ph?searchtype=author&query=Falcone%2C+A+D">A. D. Falcone</a>, <a href="/search/astro-ph?searchtype=author&query=Ford%2C+N+M">N. M. Ford</a>, <a href="/search/astro-ph?searchtype=author&query=Giroletti%2C+M">M. Giroletti</a>, <a href="/search/astro-ph?searchtype=author&query=Goddi%2C+C">C. Goddi</a>, <a href="/search/astro-ph?searchtype=author&query=Gurwell%2C+M+A">M. A. Gurwell</a>, <a href="/search/astro-ph?searchtype=author&query=Hada%2C+K">K. Hada</a>, <a href="/search/astro-ph?searchtype=author&query=Haggard%2C+D">D. Haggard</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S">S. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Kaur%2C+A">A. Kaur</a>, <a href="/search/astro-ph?searchtype=author&query=Kawashima%2C+T">T. Kawashima</a>, <a href="/search/astro-ph?searchtype=author&query=Kerby%2C+S">S. Kerby</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+J+Y">J. Y. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Kino%2C+M">M. Kino</a>, <a href="/search/astro-ph?searchtype=author&query=Kravchenko%2C+E+V">E. V. Kravchenko</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+S+S">S. S. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Lu%2C+R+S">R. S. Lu</a>, <a href="/search/astro-ph?searchtype=author&query=Markoff%2C+S">S. Markoff</a>, <a href="/search/astro-ph?searchtype=author&query=Michail%2C+J">J. Michail</a>, <a href="/search/astro-ph?searchtype=author&query=Neilsen%2C+J">J. Neilsen</a> , et al. (721 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="2404.17623v3-abstract-short" style="display: inline;"> The nearby elliptical galaxy M87 contains one of the only two supermassive black holes whose emission surrounding the event horizon has been imaged by the Event Horizon Telescope (EHT). In 2018, more than two dozen multi-wavelength (MWL) facilities (from radio to gamma-ray energies) took part in the second M87 EHT campaign. The goal of this extensive MWL campaign was to better understand the physi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.17623v3-abstract-full').style.display = 'inline'; document.getElementById('2404.17623v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.17623v3-abstract-full" style="display: none;"> The nearby elliptical galaxy M87 contains one of the only two supermassive black holes whose emission surrounding the event horizon has been imaged by the Event Horizon Telescope (EHT). In 2018, more than two dozen multi-wavelength (MWL) facilities (from radio to gamma-ray energies) took part in the second M87 EHT campaign. The goal of this extensive MWL campaign was to better understand the physics of the accreting black hole M87*, the relationship between the inflow and inner jets, and the high-energy particle acceleration. Understanding the complex astrophysics is also a necessary first step towards performing further tests of general relativity. The MWL campaign took place in April 2018, overlapping with the EHT M87* observations. We present a new, contemporaneous spectral energy distribution (SED) ranging from radio to very high energy (VHE) gamma-rays, as well as details of the individual observations and light curves. We also conduct phenomenological modelling to investigate the basic source properties. We present the first VHE gamma-ray flare from M87 detected since 2010. The flux above 350 GeV has more than doubled within a period of about 36 hours. We find that the X-ray flux is enhanced by about a factor of two compared to 2017, while the radio and millimetre core fluxes are consistent between 2017 and 2018. We detect evidence for a monotonically increasing jet position angle that corresponds to variations in the bright spot of the EHT image. Our results show the value of continued MWL monitoring together with precision imaging for addressing the origins of high-energy particle acceleration. While we cannot currently pinpoint the precise location where such acceleration takes place, the new VHE gamma-ray flare already presents a challenge to simple one-zone leptonic emission model approaches, and emphasises the need for combined image and spectral modelling. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.17623v3-abstract-full').style.display = 'none'; document.getElementById('2404.17623v3-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </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">46 pages, 23 figures, accepted by Astronomy & Astrophysics on August. 29, 2024</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 692, A140 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.12546">arXiv:2307.12546</a> <span> [<a href="https://arxiv.org/pdf/2307.12546">pdf</a>, <a href="https://arxiv.org/format/2307.12546">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"> Fermi Large Area Telescope Fourth Source Catalog Data Release 4 (4FGL-DR4) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Burnett%2C+T+H">T. H. Burnett</a>, <a href="/search/astro-ph?searchtype=author&query=Lott%2C+B">B. Lott</a>, <a href="/search/astro-ph?searchtype=author&query=collaboration%2C+T+F">The Fermi-LAT collaboration</a> </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="2307.12546v4-abstract-short" style="display: inline;"> We present an incremental version (4FGL-DR4, for Data Release 4) of the fourth Fermi-LAT catalog containing 7194 gamma-ray sources. Based on the first 14 years of science data in the energy range from 50 MeV to 1 TeV, it uses the same analysis methods as the 4FGL-DR3 catalog did for 12 years of data, with only a few improvements. The spectral parameters, spectral energy distributions, light curves… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.12546v4-abstract-full').style.display = 'inline'; document.getElementById('2307.12546v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.12546v4-abstract-full" style="display: none;"> We present an incremental version (4FGL-DR4, for Data Release 4) of the fourth Fermi-LAT catalog containing 7194 gamma-ray sources. Based on the first 14 years of science data in the energy range from 50 MeV to 1 TeV, it uses the same analysis methods as the 4FGL-DR3 catalog did for 12 years of data, with only a few improvements. The spectral parameters, spectral energy distributions, light curves and associations are updated for all sources. We add four new extended sources and modify two existing ones. Among the 6658 4FGL-DR3 sources, we delete 14 and change the localization of 10, while 32 are newly associated, eleven associations are changed and three associations are discarded. We add 546 point sources, among which 8 are considered identified and 229 have a plausible counterpart at other wavelengths. Most are just above the detection threshold, and 14 are transient sources below the detection threshold that can affect the light curves of nearby sources. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.12546v4-abstract-full').style.display = 'none'; document.getElementById('2307.12546v4-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </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">Data files at https://fermi.gsfc.nasa.gov/ssc/data/access/lat/14yr_catalog/. Refereed paper is DOI 10.3847/1538-4365/ac6751</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.11132">arXiv:2307.11132</a> <span> [<a href="https://arxiv.org/pdf/2307.11132">pdf</a>, <a href="https://arxiv.org/format/2307.11132">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/acee67">10.3847/1538-4357/acee67 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Third Fermi Large Area Telescope Catalog of Gamma-ray Pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smith%2C+D+A">David A. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">Philippe Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Clark%2C+C+J">Colin J. Clark</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">Lucas Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Kerr%2C+M+T">Matthew T. Kerr</a>, <a href="/search/astro-ph?searchtype=author&query=Ray%2C+P">Paul Ray</a>, <a href="/search/astro-ph?searchtype=author&query=Abdollahi%2C+S">Soheila Abdollahi</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">Marco Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">Luca Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">Jean Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Baring%2C+M">Matthew Baring</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C">Cees Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J+B">Josefa Becerra Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">Ronaldo Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berretta%2C+A">Alessandra Berretta</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+B">Bhaswati Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">Elisabetta Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">Raffaella Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">Eugenio Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">Johan Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">Marta Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Burnett%2C+T">Toby Burnett</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R">Rob Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Camilo%2C+F">Fernando Camilo</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">Regina Caputo</a> , et al. (134 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="2307.11132v1-abstract-short" style="display: inline;"> We present 294 pulsars found in GeV data from the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. Another 33 millisecond pulsars (MSPs) discovered in deep radio searches of LAT sources will likely reveal pulsations once phase-connected rotation ephemerides are achieved. A further dozen optical and/or X-ray binary systems co-located with LAT sources also likely harbor gamma-ray M… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.11132v1-abstract-full').style.display = 'inline'; document.getElementById('2307.11132v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.11132v1-abstract-full" style="display: none;"> We present 294 pulsars found in GeV data from the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. Another 33 millisecond pulsars (MSPs) discovered in deep radio searches of LAT sources will likely reveal pulsations once phase-connected rotation ephemerides are achieved. A further dozen optical and/or X-ray binary systems co-located with LAT sources also likely harbor gamma-ray MSPs. This catalog thus reports roughly 340 gamma-ray pulsars and candidates, 10% of all known pulsars, compared to $\leq 11$ known before Fermi. Half of the gamma-ray pulsars are young. Of these, the half that are undetected in radio have a broader Galactic latitude distribution than the young radio-loud pulsars. The others are MSPs, with 6 undetected in radio. Overall, >235 are bright enough above 50 MeV to fit the pulse profile, the energy spectrum, or both. For the common two-peaked profiles, the gamma-ray peak closest to the magnetic pole crossing generally has a softer spectrum. The spectral energy distributions tend to narrow as the spindown power $\dot E$ decreases to its observed minimum near $10^{33}$ erg s$^{-1}$, approaching the shape for synchrotron radiation from monoenergetic electrons. We calculate gamma-ray luminosities when distances are available. Our all-sky gamma-ray sensitivity map is useful for population syntheses. The electronic catalog version provides gamma-ray pulsar ephemerides, properties and fit results to guide and be compared with modeling results. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.11132v1-abstract-full').style.display = 'none'; document.getElementById('2307.11132v1-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 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </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">142 pages. Accepted by the Astrophysical Journal Supplement</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.14172">arXiv:2303.14172</a> <span> [<a href="https://arxiv.org/pdf/2303.14172">pdf</a>, <a href="https://arxiv.org/format/2303.14172">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/ace5b4">10.3847/2041-8213/ace5b4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fermi-GBM Discovery of GRB 221009A: An Extraordinarily Bright GRB from Onset to Afterglow </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lesage%2C+S">S. Lesage</a>, <a href="/search/astro-ph?searchtype=author&query=Veres%2C+P">P. Veres</a>, <a href="/search/astro-ph?searchtype=author&query=Briggs%2C+M+S">M. S. Briggs</a>, <a href="/search/astro-ph?searchtype=author&query=Goldstein%2C+A">A. Goldstein</a>, <a href="/search/astro-ph?searchtype=author&query=Kocevski%2C+D">D. Kocevski</a>, <a href="/search/astro-ph?searchtype=author&query=Burns%2C+E">E. Burns</a>, <a href="/search/astro-ph?searchtype=author&query=Wilson-Hodge%2C+C+A">C. A. Wilson-Hodge</a>, <a href="/search/astro-ph?searchtype=author&query=Bhat%2C+P+N">P. N. Bhat</a>, <a href="/search/astro-ph?searchtype=author&query=Huppenkothen%2C+D">D. Huppenkothen</a>, <a href="/search/astro-ph?searchtype=author&query=Fryer%2C+C+L">C. L. Fryer</a>, <a href="/search/astro-ph?searchtype=author&query=Hamburg%2C+R">R. Hamburg</a>, <a href="/search/astro-ph?searchtype=author&query=Racusin%2C+J">J. Racusin</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Cleveland%2C+W+H">W. H. Cleveland</a>, <a href="/search/astro-ph?searchtype=author&query=Dalessi%2C+S">S. Dalessi</a>, <a href="/search/astro-ph?searchtype=author&query=Fletcher%2C+C">C. Fletcher</a>, <a href="/search/astro-ph?searchtype=author&query=Giles%2C+M+M">M. M. Giles</a>, <a href="/search/astro-ph?searchtype=author&query=Hristov%2C+B+A">B. A. Hristov</a>, <a href="/search/astro-ph?searchtype=author&query=Hui%2C+C+M">C. M. Hui</a>, <a href="/search/astro-ph?searchtype=author&query=Mailyan%2C+B">B. Mailyan</a>, <a href="/search/astro-ph?searchtype=author&query=Malacaria%2C+C">C. Malacaria</a>, <a href="/search/astro-ph?searchtype=author&query=Poolakkil%2C+S">S. Poolakkil</a>, <a href="/search/astro-ph?searchtype=author&query=Roberts%2C+O+J">O. J. Roberts</a>, <a href="/search/astro-ph?searchtype=author&query=von+Kienlin%2C+A">A. von Kienlin</a>, <a href="/search/astro-ph?searchtype=author&query=Wood%2C+J">J. Wood</a> , et al. (115 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="2303.14172v2-abstract-short" style="display: inline;"> We report the discovery of GRB 221009A, the highest flux gamma-ray burst ever observed by the Fermi Gamma-ray Burst Monitor (GBM). This GRB has continuous prompt emission lasting more than 600 seconds which smoothly transitions to afterglow visible in the GBM energy range (8 keV--40 MeV), and total energetics higher than any other burst in the GBM sample. By using a variety of new and existing ana… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.14172v2-abstract-full').style.display = 'inline'; document.getElementById('2303.14172v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.14172v2-abstract-full" style="display: none;"> We report the discovery of GRB 221009A, the highest flux gamma-ray burst ever observed by the Fermi Gamma-ray Burst Monitor (GBM). This GRB has continuous prompt emission lasting more than 600 seconds which smoothly transitions to afterglow visible in the GBM energy range (8 keV--40 MeV), and total energetics higher than any other burst in the GBM sample. By using a variety of new and existing analysis techniques we probe the spectral and temporal evolution of GRB 221009A. We find no emission prior to the GBM trigger time (t0; 2022 October 9 at 13:16:59.99 UTC), indicating that this is the time of prompt emission onset. The triggering pulse exhibits distinct spectral and temporal properties suggestive of the thermal, photospheric emission of shock-breakout, with significant emission up to $\sim$15 MeV. We characterize the onset of external shock at t0+600 s and find evidence of a plateau region in the early-afterglow phase which transitions to a slope consistent with Swift-XRT afterglow measurements. We place the total energetics of GRB 221009A in context with the rest of the GBM sample and find that this GRB has the highest total isotropic-equivalent energy ($\textrm{E}_{纬,\textrm{iso}}=1.0\times10^{55}$ erg) and second highest isotropic-equivalent luminosity ($\textrm{L}_{纬,\textrm{iso}}=9.9\times10^{53}$ erg/s) based on redshift of z = 0.151. These extreme energetics are what allowed us to observe the continuously emitting central engine of GBM from the beginning of the prompt emission phase through the onset of early afterglow. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.14172v2-abstract-full').style.display = 'none'; document.getElementById('2303.14172v2-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </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">26 pages 7 figures - accepted for publication in ApJL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.10995">arXiv:2301.10995</a> <span> [<a href="https://arxiv.org/pdf/2301.10995">pdf</a>, <a href="https://arxiv.org/format/2301.10995">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/10.1038/s41550-022-01874-x">10.1038/s41550-022-01874-x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Neutron star mass estimates from gamma-ray eclipses in spider millisecond pulsar binaries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Clark%2C+C+J">C. J. Clark</a>, <a href="/search/astro-ph?searchtype=author&query=Kerr%2C+M">M. Kerr</a>, <a href="/search/astro-ph?searchtype=author&query=Barr%2C+E+D">E. D. Barr</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+B">B. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Breton%2C+R+P">R. P. Breton</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Camilo%2C+F">F. Camilo</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+W">W. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Cromartie%2C+H+T">H. T. Cromartie</a>, <a href="/search/astro-ph?searchtype=author&query=Deneva%2C+J">J. Deneva</a>, <a href="/search/astro-ph?searchtype=author&query=Dhillon%2C+V+S">V. S. Dhillon</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">L. Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Kennedy%2C+M+R">M. R. Kennedy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lyne%2C+A+G">A. G. Lyne</a>, <a href="/search/astro-ph?searchtype=author&query=S%C3%A1nchez%2C+D+M">D. Mata S谩nchez</a>, <a href="/search/astro-ph?searchtype=author&query=Nieder%2C+L">L. Nieder</a>, <a href="/search/astro-ph?searchtype=author&query=Phillips%2C+C">C. Phillips</a>, <a href="/search/astro-ph?searchtype=author&query=Ransom%2C+S+M">S. M. Ransom</a>, <a href="/search/astro-ph?searchtype=author&query=Ray%2C+P+S">P. S. Ray</a>, <a href="/search/astro-ph?searchtype=author&query=Roberts%2C+M+S+E">M. S. E. Roberts</a>, <a href="/search/astro-ph?searchtype=author&query=Roy%2C+J">J. Roy</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+D+A">D. A. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Spiewak%2C+R">R. Spiewak</a> , et al. (4 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="2301.10995v1-abstract-short" style="display: inline;"> Reliable neutron star mass measurements are key to determining the equation-of-state of cold nuclear matter, but these are rare. "Black Widows" and "Redbacks" are compact binaries consisting of millisecond pulsars and semi-degenerate companion stars. Spectroscopy of the optically bright companions can determine their radial velocities, providing inclination-dependent pulsar mass estimates. While i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.10995v1-abstract-full').style.display = 'inline'; document.getElementById('2301.10995v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.10995v1-abstract-full" style="display: none;"> Reliable neutron star mass measurements are key to determining the equation-of-state of cold nuclear matter, but these are rare. "Black Widows" and "Redbacks" are compact binaries consisting of millisecond pulsars and semi-degenerate companion stars. Spectroscopy of the optically bright companions can determine their radial velocities, providing inclination-dependent pulsar mass estimates. While inclinations can be inferred from subtle features in optical light curves, such estimates may be systematically biased due to incomplete heating models and poorly-understood variability. Using data from the Fermi Large Area Telescope, we have searched for gamma-ray eclipses from 49 spider systems, discovering significant eclipses in 7 systems, including the prototypical black widow PSR B1957$+$20. Gamma-ray eclipses require direct occultation of the pulsar by the companion, and so the detection, or significant exclusion, of a gamma-ray eclipse strictly limits the binary inclination angle, providing new robust, model-independent pulsar mass constraints. For PSR B1957$+$20, the eclipse implies a much lighter pulsar ($M_{\rm psr} = 1.81 \pm 0.07\,M_{\odot}$) than inferred from optical light curve modelling. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.10995v1-abstract-full').style.display = 'none'; document.getElementById('2301.10995v1-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 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </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">31 pages, 4 figures, includes supplementary tables; published 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/2301.01607">arXiv:2301.01607</a> <span> [<a href="https://arxiv.org/pdf/2301.01607">pdf</a>, <a href="https://arxiv.org/format/2301.01607">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/acbb6a">10.3847/1538-4365/acbb6a <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Fermi-LAT Light Curve Repository </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abdollahi%2C+S">S. Abdollahi</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J+B">J. Becerra Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berretta%2C+A">A. Berretta</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">A. Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Burns%2C+E">E. Burns</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+A">A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R. Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cibrario%2C+N">N. Cibrario</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Orestano%2C+P+C">P. Cristarella Orestano</a>, <a href="/search/astro-ph?searchtype=author&query=Crnogorcevic%2C+M">M. Crnogorcevic</a>, <a href="/search/astro-ph?searchtype=author&query=Cutini%2C+S">S. Cutini</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Ammando%2C+F">F. D'Ammando</a>, <a href="/search/astro-ph?searchtype=author&query=De+Gaetano%2C+S">S. De Gaetano</a>, <a href="/search/astro-ph?searchtype=author&query=Digel%2C+S+W">S. W. Digel</a> , et al. (88 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="2301.01607v2-abstract-short" style="display: inline;"> The Fermi Large Area Telescope (LAT) light curve repository (LCR) is a publicly available, continually updated library of gamma-ray light curves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality light curves binned on timescales of 3 days, 7 days, and 30 days for 1525 sources deemed variable in the source catalog of the first 10… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.01607v2-abstract-full').style.display = 'inline'; document.getElementById('2301.01607v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.01607v2-abstract-full" style="display: none;"> The Fermi Large Area Telescope (LAT) light curve repository (LCR) is a publicly available, continually updated library of gamma-ray light curves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality light curves binned on timescales of 3 days, 7 days, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 years of Fermi-LAT observations. The repository consists of light curves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multi-messenger communities by allowing users to quickly search LAT data to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.01607v2-abstract-full').style.display = 'none'; document.getElementById('2301.01607v2-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 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </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 Supplement Series</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.12070">arXiv:2209.12070</a> <span> [<a href="https://arxiv.org/pdf/2209.12070">pdf</a>, <a href="https://arxiv.org/ps/2209.12070">ps</a>, <a href="https://arxiv.org/format/2209.12070">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="Astrophysics of Galaxies">astro-ph.GA</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/ac9523">10.3847/1538-4365/ac9523 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope -- Data Release 3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=collaboration%2C+T+F">The Fermi-LAT collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=%3A"> :</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">Marco Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">Luca Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">Jean Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">Denis Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J+B">Josefa Becerra Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">Ronaldo Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berretta%2C+A">Alessandra Berretta</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">Elisabetta Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">Raffaella Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">Ari Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">Philippe Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">Sara Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">Regina Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P">Patrizia Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+T">Teddy Cheung</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">Graziano Chiaro</a>, <a href="/search/astro-ph?searchtype=author&query=Cibrario%2C+N">Nicolo Cibrario</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">Stefano Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Crnogorcevic%2C+M">Milena Crnogorcevic</a>, <a href="/search/astro-ph?searchtype=author&query=Cutini%2C+S">Sara Cutini</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Ammando%2C+F">Filippo D'Ammando</a>, <a href="/search/astro-ph?searchtype=author&query=De+Gaetano%2C+S">Salvatore De Gaetano</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Lalla%2C+N">Niccolo Di Lalla</a> , et al. (79 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="2209.12070v2-abstract-short" style="display: inline;"> An incremental version of the fourth catalog of active galactic nuclei (AGNs) detected by the Fermi-Large Area Telescope is presented. This version (4LAC-DR3) derives from the third data release of the 4FGL catalog based on 12 years of E>50 MeV gamma-ray data, where the spectral parameters, spectral energy distributions (SEDs), yearly light curves, and associations have been updated for all source… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.12070v2-abstract-full').style.display = 'inline'; document.getElementById('2209.12070v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.12070v2-abstract-full" style="display: none;"> An incremental version of the fourth catalog of active galactic nuclei (AGNs) detected by the Fermi-Large Area Telescope is presented. This version (4LAC-DR3) derives from the third data release of the 4FGL catalog based on 12 years of E>50 MeV gamma-ray data, where the spectral parameters, spectral energy distributions (SEDs), yearly light curves, and associations have been updated for all sources. The new reported AGNs include 587 blazar candidates and four radio galaxies. We describe the properties of the new sample and outline changes affecting the previously published one. We also introduce two new parameters in this release, namely the peak energy of the SED high-energy component and the corresponding flux. These parameters allow an assessment of the Compton dominance, the ratio of the Inverse-Compton to the synchrotron peak luminosities, without relying on X-ray data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.12070v2-abstract-full').style.display = 'none'; document.getElementById('2209.12070v2-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2022. </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, 7 figures, accepted for publication in The Astrophysical Journal Supplement Series. Fits files are available at https://fermi.gsfc.nasa.gov/ssc/data/access/lat/4LACDR3/ or alternatively at https://www.ssdc.asi.it/fermi4lac-DR3/table-4LAC-DR3-h.fits and https://www.ssdc.asi.it/fermi4lac-DR3/table-4LAC-DR3-l.fits</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2205.03111">arXiv:2205.03111</a> <span> [<a href="https://arxiv.org/pdf/2205.03111">pdf</a>, <a href="https://arxiv.org/format/2205.03111">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/ac704f">10.3847/1538-4357/ac704f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for new cosmic-ray acceleration sites within the 4FGL catalog Galactic plane sources </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Collaboration%2C+F">Fermi-LAT Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Abdollahi%2C+S">S. Abdollahi</a>, <a href="/search/astro-ph?searchtype=author&query=Acero%2C+F">F. Acero</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berenji%2C+B">B. Berenji</a>, <a href="/search/astro-ph?searchtype=author&query=Berretta%2C+A">A. Berretta</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R. Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+D">D. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">G. Chiaro</a>, <a href="/search/astro-ph?searchtype=author&query=Cibrario%2C+N">N. Cibrario</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Coronado-Bl%C3%A1zquez%2C+J">J. Coronado-Bl谩zquez</a>, <a href="/search/astro-ph?searchtype=author&query=Crnogorcevic%2C+M">M. Crnogorcevic</a> , et al. (95 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="2205.03111v1-abstract-short" style="display: inline;"> Cosmic rays are mostly composed of protons accelerated to relativistic speeds. When those protons encounter interstellar material, they produce neutral pions which in turn decay into gamma rays. This offers a compelling way to identify the acceleration sites of protons. A characteristic hadronic spectrum, with a low-energy break around 200 MeV, was detected in the gamma-ray spectra of four Superno… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.03111v1-abstract-full').style.display = 'inline'; document.getElementById('2205.03111v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.03111v1-abstract-full" style="display: none;"> Cosmic rays are mostly composed of protons accelerated to relativistic speeds. When those protons encounter interstellar material, they produce neutral pions which in turn decay into gamma rays. This offers a compelling way to identify the acceleration sites of protons. A characteristic hadronic spectrum, with a low-energy break around 200 MeV, was detected in the gamma-ray spectra of four Supernova Remnants (SNRs), IC 443, W44, W49B and W51C, with the Fermi Large Area Telescope. This detection provided direct evidence that cosmic-ray protons are (re-)accelerated in SNRs. Here, we present a comprehensive search for low-energy spectral breaks among 311 4FGL catalog sources located within 5 degrees from the Galactic plane. Using 8 years of data from the Fermi Large Area Telescope between 50 MeV and 1 GeV, we find and present the spectral characteristics of 56 sources with a spectral break confirmed by a thorough study of systematic uncertainty. Our population of sources includes 13 SNRs for which the proton-proton interaction is enhanced by the dense target material; the high-mass gamma-ray binary LS~I +61 303; the colliding wind binary eta Carinae; and the Cygnus star-forming region. This analysis better constrains the origin of the gamma-ray emission and enlarges our view to potential new cosmic-ray acceleration sites. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.03111v1-abstract-full').style.display = 'none'; document.getElementById('2205.03111v1-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2022. </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/2204.05226">arXiv:2204.05226</a> <span> [<a href="https://arxiv.org/pdf/2204.05226">pdf</a>, <a href="https://arxiv.org/format/2204.05226">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/10.1126/science.abm3231">10.1126/science.abm3231 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Gamma-ray Pulsar Timing Array Constrains the Nanohertz Gravitational Wave Background </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Atwood%2C+W+B">W. B. Atwood</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berretta%2C+A">A. Berretta</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+B">B. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E">E. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Burns%2C+E">E. Burns</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cibrario%2C+N">N. Cibrario</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Clark%2C+C+J">C. J. Clark</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Coronado-Bl%C3%A1zquez%2C+J">J. Coronado-Bl谩zquez</a> , et al. (107 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="2204.05226v1-abstract-short" style="display: inline;"> After large galaxies merge, their central supermassive black holes are expected to form binary systems whose orbital motion generates a gravitational wave background (GWB) at nanohertz frequencies. Searches for this background utilize pulsar timing arrays, which perform long-term monitoring of millisecond pulsars (MSPs) at radio wavelengths. We use 12.5 years of Fermi Large Area Telescope data to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.05226v1-abstract-full').style.display = 'inline'; document.getElementById('2204.05226v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.05226v1-abstract-full" style="display: none;"> After large galaxies merge, their central supermassive black holes are expected to form binary systems whose orbital motion generates a gravitational wave background (GWB) at nanohertz frequencies. Searches for this background utilize pulsar timing arrays, which perform long-term monitoring of millisecond pulsars (MSPs) at radio wavelengths. We use 12.5 years of Fermi Large Area Telescope data to form a gamma-ray pulsar timing array. Results from 35 bright gamma-ray pulsars place a 95\% credible limit on the GWB characteristic strain of $1.0\times10^{-14}$ at 1 yr$^{-1}$, which scales as the observing time span $t_{\mathrm{obs}}^{-13/6}$. This direct measurement provides an independent probe of the GWB while offering a check on radio noise models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.05226v1-abstract-full').style.display = 'none'; document.getElementById('2204.05226v1-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 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </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">3 figures in the main text. 3 figures and 8 tables are in the supplementary material</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.05482">arXiv:2202.05482</a> <span> [<a href="https://arxiv.org/pdf/2202.05482">pdf</a>, <a href="https://arxiv.org/format/2202.05482">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/ac6b35">10.3847/2041-8213/ac6b35 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Is the black-widow pulsar PSR J1555-2908 in a hierarchical triple system? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nieder%2C+L">L. Nieder</a>, <a href="/search/astro-ph?searchtype=author&query=Kerr%2C+M">M. Kerr</a>, <a href="/search/astro-ph?searchtype=author&query=Clark%2C+C+J">C. J. Clark</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Cromartie%2C+H+T">H. T. Cromartie</a>, <a href="/search/astro-ph?searchtype=author&query=Ransom%2C+S+M">S. M. Ransom</a>, <a href="/search/astro-ph?searchtype=author&query=Ray%2C+P+S">P. S. Ray</a> </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="2202.05482v1-abstract-short" style="display: inline;"> The 559 Hz black-widow pulsar PSR J1555-2908, originally discovered in radio, is also a bright gamma-ray pulsar. Timing its pulsations using 12 yr of Fermi-LAT gamma-ray data reveals long-term variations in its spin frequency that are much larger than is observed from other millisecond pulsars. While this variability in the pulsar rotation rate could be intrinsic "timing noise", here we consider a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.05482v1-abstract-full').style.display = 'inline'; document.getElementById('2202.05482v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.05482v1-abstract-full" style="display: none;"> The 559 Hz black-widow pulsar PSR J1555-2908, originally discovered in radio, is also a bright gamma-ray pulsar. Timing its pulsations using 12 yr of Fermi-LAT gamma-ray data reveals long-term variations in its spin frequency that are much larger than is observed from other millisecond pulsars. While this variability in the pulsar rotation rate could be intrinsic "timing noise", here we consider an alternative explanation: the variations arise from the presence of a very-low-mass third object in a wide multi-year orbit around the neutron star and its low-mass companion. With current data, this hierarchical-triple-system model describes the pulsar's rotation slightly more accurately than the best-fitting timing-noise model. Future observations will show if this alternative explanation is correct. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.05482v1-abstract-full').style.display = 'none'; document.getElementById('2202.05482v1-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 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </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, 2 figures, submitted to ApJL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.04783">arXiv:2202.04783</a> <span> [<a href="https://arxiv.org/pdf/2202.04783">pdf</a>, <a href="https://arxiv.org/format/2202.04783">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/ac49ef">10.3847/1538-4357/ac49ef <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discovery, Timing, and Multiwavelength Observations of the Black Widow Millisecond Pulsar PSR J1555-2908 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ray%2C+P+S">Paul S. Ray</a>, <a href="/search/astro-ph?searchtype=author&query=Nieder%2C+L">Lars Nieder</a>, <a href="/search/astro-ph?searchtype=author&query=Clark%2C+C+J">Colin J. Clark</a>, <a href="/search/astro-ph?searchtype=author&query=Ransom%2C+S+M">Scott M. Ransom</a>, <a href="/search/astro-ph?searchtype=author&query=Cromartie%2C+H+T">H. Thankful Cromartie</a>, <a href="/search/astro-ph?searchtype=author&query=Frail%2C+D+A">Dale A. Frail</a>, <a href="/search/astro-ph?searchtype=author&query=Mooley%2C+K+P">Kunal P. Mooley</a>, <a href="/search/astro-ph?searchtype=author&query=Intema%2C+H">Huib Intema</a>, <a href="/search/astro-ph?searchtype=author&query=Jagannathan%2C+P">Preshanth Jagannathan</a>, <a href="/search/astro-ph?searchtype=author&query=Demorest%2C+P">Paul Demorest</a>, <a href="/search/astro-ph?searchtype=author&query=Stovall%2C+K">Kevin Stovall</a>, <a href="/search/astro-ph?searchtype=author&query=Halpern%2C+J+P">Jules P. Halpern</a>, <a href="/search/astro-ph?searchtype=author&query=Deneva%2C+J">Julia Deneva</a>, <a href="/search/astro-ph?searchtype=author&query=Guillot%2C+S">Sebastien Guillot</a>, <a href="/search/astro-ph?searchtype=author&query=Kerr%2C+M">Matthew Kerr</a>, <a href="/search/astro-ph?searchtype=author&query=Swihart%2C+S+J">Samuel J. Swihart</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">Philippe Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">Ben W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Lyne%2C+A">Andrew Lyne</a>, <a href="/search/astro-ph?searchtype=author&query=Mickaliger%2C+M">Mitch Mickaliger</a>, <a href="/search/astro-ph?searchtype=author&query=Camilo%2C+F">Fernando Camilo</a>, <a href="/search/astro-ph?searchtype=author&query=Ferrara%2C+E+C">Elizabeth C. Ferrara</a>, <a href="/search/astro-ph?searchtype=author&query=Wolff%2C+M+T">Michael T. Wolff</a>, <a href="/search/astro-ph?searchtype=author&query=Michelson%2C+P+F">P. F. Michelson</a> </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="2202.04783v1-abstract-short" style="display: inline;"> We report the discovery of PSR J1555-2908, a 1.79 ms radio and gamma-ray pulsar in a 5.6 hr binary system with a minimum companion mass of 0.052 $M_\odot$. This fast and energetic ($\dot E = 3 \times 10^{35}$ erg/s) millisecond pulsar was first detected as a gamma-ray point source in Fermi LAT sky survey observations. Guided by a steep spectrum radio point source in the Fermi error region, we perf… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.04783v1-abstract-full').style.display = 'inline'; document.getElementById('2202.04783v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.04783v1-abstract-full" style="display: none;"> We report the discovery of PSR J1555-2908, a 1.79 ms radio and gamma-ray pulsar in a 5.6 hr binary system with a minimum companion mass of 0.052 $M_\odot$. This fast and energetic ($\dot E = 3 \times 10^{35}$ erg/s) millisecond pulsar was first detected as a gamma-ray point source in Fermi LAT sky survey observations. Guided by a steep spectrum radio point source in the Fermi error region, we performed a search at 820 MHz with the Green Bank Telescope that first discovered the pulsations. The initial radio pulse timing observations provided enough information to seed a search for gamma-ray pulsations in the LAT data, from which we derive a timing solution valid for the full Fermi mission. In addition to the radio and gamma-ray pulsation discovery and timing, we searched for X-ray pulsations using NICER but no significant pulsations were detected. We also obtained time-series r-band photometry that indicates strong heating of the companion star by the pulsar wind. Material blown off the heated companion eclipses the 820 MHz radio pulse during inferior conjunction of the companion for ~10% of the orbit, which is twice the angle subtended by its Roche lobe in an edge-on system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.04783v1-abstract-full').style.display = 'none'; document.getElementById('2202.04783v1-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 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </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">15 pages, 6 figures, 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/2201.11184">arXiv:2201.11184</a> <span> [<a href="https://arxiv.org/pdf/2201.11184">pdf</a>, <a href="https://arxiv.org/format/2201.11184">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/ac6751">10.3847/1538-4365/ac6751 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Incremental Fermi Large Area Telescope Fourth Source Catalog </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=collaboration%2C+F">Fermi-LAT collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=%3A"> :</a>, <a href="/search/astro-ph?searchtype=author&query=Abdollahi%2C+S">Soheila Abdollahi</a>, <a href="/search/astro-ph?searchtype=author&query=Acero%2C+F">Fabio Acero</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">Luca Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">Jean Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">Denis Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">Ronaldo Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berenji%2C+B">Bijan Berenji</a>, <a href="/search/astro-ph?searchtype=author&query=Berretta%2C+A">Alessandra Berretta</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">Elisabetta Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">Roger D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E">Elliott Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">Raffaella Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Brill%2C+A">Ari Brill</a>, <a href="/search/astro-ph?searchtype=author&query=Britto%2C+R+J">Richard J. Britto</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">Philippe Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Burnett%2C+T+H">Toby H. Burnett</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">Sara Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">Rob A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">Regina Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">Patrizia A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+D">Daniel Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Chaty%2C+S">Sylvain Chaty</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+T+C">Teddy C. Cheung</a> , et al. (116 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="2201.11184v3-abstract-short" style="display: inline;"> We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi-LAT catalog of gamma-ray sources. Based on the first twelve years of science data in the energy range from 50 MeV to 1 TeV, it contains 6658 sources. The analysis improves on that used for the 4FGL catalog over eight years of data: more sources are fit with curved spectra, we introduce a more robust spectral param… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.11184v3-abstract-full').style.display = 'inline'; document.getElementById('2201.11184v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.11184v3-abstract-full" style="display: none;"> We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi-LAT catalog of gamma-ray sources. Based on the first twelve years of science data in the energy range from 50 MeV to 1 TeV, it contains 6658 sources. The analysis improves on that used for the 4FGL catalog over eight years of data: more sources are fit with curved spectra, we introduce a more robust spectral parameterization for pulsars, and we extend the spectral points to 1 TeV. The spectral parameters, spectral energy distributions, and associations are updated for all sources. Light curves are rebuilt for all sources with 1 yr intervals (not 2 month intervals). Among the 5064 original 4FGL sources, 16 were deleted, 112 are formally below the detection threshold over 12 yr (but are kept in the list), while 74 are newly associated, 10 have an improved association, and seven associations were withdrawn. Pulsars are split explicitly between young and millisecond pulsars. Pulsars and binaries newly detected in LAT sources, as well as more than 100 newly classified blazars, are reported. We add three extended sources and 1607 new point sources, mostly just above the detection threshold, among which eight are considered identified, and 699 have a plausible counterpart at other wavelengths. We discuss degree-scale residuals to the global sky model and clusters of soft unassociated point sources close to the Galactic plane, which are possibly related to limitations of the interstellar emission model and missing extended sources. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.11184v3-abstract-full').style.display = 'none'; document.getElementById('2201.11184v3-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 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </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 in ApJS; follow-up paper to 1902.10045</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJS 260, 53 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.07443">arXiv:2109.07443</a> <span> [<a href="https://arxiv.org/pdf/2109.07443">pdf</a>, <a href="https://arxiv.org/format/2109.07443">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="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/10.1051/0004-6361/202141553">10.1051/0004-6361/202141553 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A new method to perform data/model comparison in Fermi-LAT analysis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a> </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="2109.07443v1-abstract-short" style="display: inline;"> The analysis of Fermi Large Area Telescope (LAT) gamma-ray data in a given Region Of Interest (RoI) usually consists of performing a binned log-likelihood fit in order to determine the sky model that, after convolution with the instrument response, best accounts for the distribution of observed counts. While tools are available to perform such a fit, it is not easy to check the goodness-of-fit. Th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.07443v1-abstract-full').style.display = 'inline'; document.getElementById('2109.07443v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.07443v1-abstract-full" style="display: none;"> The analysis of Fermi Large Area Telescope (LAT) gamma-ray data in a given Region Of Interest (RoI) usually consists of performing a binned log-likelihood fit in order to determine the sky model that, after convolution with the instrument response, best accounts for the distribution of observed counts. While tools are available to perform such a fit, it is not easy to check the goodness-of-fit. The difficulty of the assessment of the data/model agreement is twofold. First of all, the observed and predicted counts are binned in three dimensions (two spatial dimensions and one energy dimension) and comparing two 3D maps is not straightforward. Secondly, gamma-ray source spectra generally decrease with energy as the inverse of the energy square. As a consequence the number of counts above several GeV generally falls into the Poisson regime, which precludes performing a simple $蠂^2$ test. We propose a method that overcomes these two obstacles by producing and comparing spatially integrated count spectra for data and model at each pixel of the analysed RoI. The comparison is performed following a log-likelihood approach that extends the $蠂^2$ test to histograms with low statistics. This method can take into account likelihood weights that are used to account for systematic uncertainties. We optimize the new method so that it provides a fast and reliable tool to assess the goodness-of-fit of Fermi-LAT data and we use it to check the latest gamma-ray source catalog on 10~years of data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.07443v1-abstract-full').style.display = 'none'; document.getElementById('2109.07443v1-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, 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 in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 656, A81 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.12203">arXiv:2106.12203</a> <span> [<a href="https://arxiv.org/pdf/2106.12203">pdf</a>, <a href="https://arxiv.org/format/2106.12203">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/10.3847/1538-4365/ac0ceb">10.3847/1538-4365/ac0ceb <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fermi Large Area Telescope Performance After 10 Years Of Operation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+Fermi+LAT+Collaboration"> The Fermi LAT Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Atwood%2C+W+B">W. B. Atwood</a>, <a href="/search/astro-ph?searchtype=author&query=Axelsson%2C+M">M. Axelsson</a>, <a href="/search/astro-ph?searchtype=author&query=Bagagli%2C+R">R. Bagagli</a>, <a href="/search/astro-ph?searchtype=author&query=Bagni%2C+M">M. Bagni</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellardi%2C+F">F. Bellardi</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Brez%2C+A">A. Brez</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Ceccanti%2C+M">M. Ceccanti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S">S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+C+C">C. C. Cheung</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a> , et al. (104 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="2106.12203v3-abstract-short" style="display: inline;"> The Large Area Telescope (LAT), the primary instrument for the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the energy range from 30 MeV to more than 300 GeV. We describe the performance of the instrument at the 10-year milestone. LAT performance remains well within the specifications defined during the planning phase… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.12203v3-abstract-full').style.display = 'inline'; document.getElementById('2106.12203v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.12203v3-abstract-full" style="display: none;"> The Large Area Telescope (LAT), the primary instrument for the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the energy range from 30 MeV to more than 300 GeV. We describe the performance of the instrument at the 10-year milestone. LAT performance remains well within the specifications defined during the planning phase, validating the design choices and supporting the compelling case to extend the duration of the Fermi mission. The details provided here will be useful when designing the next generation of high-energy gamma-ray observatories. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.12203v3-abstract-full').style.display = 'none'; document.getElementById('2106.12203v3-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, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">60 pages, 28 figures. Published in ApJS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJS 256 (2021) 12 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.00100">arXiv:2106.00100</a> <span> [<a href="https://arxiv.org/pdf/2106.00100">pdf</a>, <a href="https://arxiv.org/format/2106.00100">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/ac072a">10.3847/1538-4365/ac072a <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Catalog of Long-Term Transient Sources in the First 10 Years of Fermi-LAT Data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J+B">J. Becerra Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berretta%2C+A">A. Berretta</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S">S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">G. Chiaro</a>, <a href="/search/astro-ph?searchtype=author&query=Ciangottini%2C+D">D. Ciangottini</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Orestano%2C+P+C">P. Cristarella Orestano</a>, <a href="/search/astro-ph?searchtype=author&query=Crnogorcevic%2C+M">M. Crnogorcevic</a>, <a href="/search/astro-ph?searchtype=author&query=Cutini%2C+S">S. Cutini</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Ammando%2C+F">F. D'Ammando</a>, <a href="/search/astro-ph?searchtype=author&query=Luque%2C+P+d+l+T">P. de la Torre Luque</a> , et al. (90 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="2106.00100v1-abstract-short" style="display: inline;"> We present the first Fermi Large Area Telescope (LAT) catalog of long-term $纬$-ray transient sources (1FLT). This comprises sources that were detected on monthly time intervals during the first decade of Fermi-LAT operations. The monthly time scale allows us to identify transient and variable sources that were not yet reported in other Fermi-LAT catalogs. The monthly datasets were analyzed using a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.00100v1-abstract-full').style.display = 'inline'; document.getElementById('2106.00100v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.00100v1-abstract-full" style="display: none;"> We present the first Fermi Large Area Telescope (LAT) catalog of long-term $纬$-ray transient sources (1FLT). This comprises sources that were detected on monthly time intervals during the first decade of Fermi-LAT operations. The monthly time scale allows us to identify transient and variable sources that were not yet reported in other Fermi-LAT catalogs. The monthly datasets were analyzed using a wavelet-based source detection algorithm that provided the candidate new transient sources. The search was limited to the extragalactic regions of the sky to avoid the dominance of the Galactic diffuse emission at low Galactic latitudes. The transient candidates were then analyzed using the standard Fermi-LAT Maximum Likelihood analysis method. All sources detected with a statistical significance above 4$蟽$ in at least one monthly bin were listed in the final catalog. The 1FLT catalog contains 142 transient $纬$-ray sources that are not included in the 4FGL-DR2 catalog. Many of these sources (102) have been confidently associated with Active Galactic Nuclei (AGN): 24 are associated with Flat Spectrum Radio Quasars; 1 with a BL Lac object; 70 with Blazars of Uncertain Type; 3 with Radio Galaxies; 1 with a Compact Steep Spectrum radio source; 1 with a Steep Spectrum Radio Quasar; 2 with AGN of other types. The remaining 40 sources have no candidate counterparts at other wavelengths. The median $纬$-ray spectral index of the 1FLT-AGN sources is softer than that reported in the latest Fermi-LAT AGN general catalog. This result is consistent with the hypothesis that detection of the softest $纬$-ray emitters is less efficient when the data are integrated over year-long intervals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.00100v1-abstract-full').style.display = 'none'; document.getElementById('2106.00100v1-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> 31 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">41 pages, 17 figures, 7 tables; Accepted by ApJS on 24 May 2021; Contact Authors: I. Mereu, S. Cutini, E. Cavazzuti, G. Tosti</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.10010">arXiv:2101.10010</a> <span> [<a href="https://arxiv.org/pdf/2101.10010">pdf</a>, <a href="https://arxiv.org/format/2101.10010">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="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/10.3847/1538-4365/abd32e">10.3847/1538-4365/abd32e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The First Fermi-LAT Solar Flare Catalog </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berretta%2C+A">A. Berretta</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R. Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+C+C">C. C. Cheung</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">G. Chiaro</a>, <a href="/search/astro-ph?searchtype=author&query=Costantin%2C+D">D. Costantin</a>, <a href="/search/astro-ph?searchtype=author&query=Cutini%2C+S">S. Cutini</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Ammando%2C+F">F. D'Ammando</a>, <a href="/search/astro-ph?searchtype=author&query=de+Palma%2C+F">F. de Palma</a>, <a href="/search/astro-ph?searchtype=author&query=Desiante%2C+R">R. Desiante</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Lalla%2C+N">N. Di Lalla</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Venere%2C+L">L. Di Venere</a>, <a href="/search/astro-ph?searchtype=author&query=Dirirsa%2C+F+F">F. Fana Dirirsa</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=Fukazawa%2C+Y">Y. Fukazawa</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="2101.10010v1-abstract-short" style="display: inline;"> We present the first Fermi - Large Area Telescope (LAT) solar flare catalog covering the 24 th solar cycle. This catalog contains 45 Fermi -LAT solar flares (FLSFs) with emission in the gamma-ray energy band (30 MeV - 10 GeV) detected with a significance greater than 5 sigma over the years 2010-2018. A subsample containing 37 of these flares exhibit delayed emission beyond the prompt-impulsive har… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.10010v1-abstract-full').style.display = 'inline'; document.getElementById('2101.10010v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.10010v1-abstract-full" style="display: none;"> We present the first Fermi - Large Area Telescope (LAT) solar flare catalog covering the 24 th solar cycle. This catalog contains 45 Fermi -LAT solar flares (FLSFs) with emission in the gamma-ray energy band (30 MeV - 10 GeV) detected with a significance greater than 5 sigma over the years 2010-2018. A subsample containing 37 of these flares exhibit delayed emission beyond the prompt-impulsive hard X-ray phase with 21 flares showing delayed emission lasting more than two hours. No prompt-impulsive emission is detected in four of these flares. We also present in this catalog the observations of GeV emission from 3 flares originating from Active Regions located behind the limb (BTL) of the visible solar disk. We report the light curves, spectra, best proton index and localization (when possible) for all the FLSFs. The gamma-ray spectra is consistent with the decay of pions produced by >300 MeV protons. This work contains the largest sample of high-energy gamma-ray flares ever reported and provides the unique opportunity to perform population studies on the different phases of the flare and thus allowing to open a new window in solar physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.10010v1-abstract-full').style.display = 'none'; document.getElementById('2101.10010v1-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> 25 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">Published in ApJS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJS 252 13 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1909.10605">arXiv:1909.10605</a> <span> [<a href="https://arxiv.org/pdf/1909.10605">pdf</a>, <a href="https://arxiv.org/format/1909.10605">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/ab5b05">10.3847/1538-4357/ab5b05 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fermi and Swift Observations of GRB 190114C: Tracing the Evolution of High-Energy Emission from Prompt to Afterglow </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Arimoto%2C+M">M. Arimoto</a>, <a href="/search/astro-ph?searchtype=author&query=Axelsson%2C+M">M. Axelsson</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Berretta%2C+A">A. Berretta</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Burns%2C+E">E. Burns</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R. Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S">S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">G. Chiaro</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen-Tanugi%2C+J">J. Cohen-Tanugi</a> , et al. (125 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="1909.10605v2-abstract-short" style="display: inline;"> We report on the observations of gamma-ray burst (GRB) 190114C by the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory. The early-time observations reveal multiple emission components that evolve independently, with a delayed power-law component that exhibits significant spectral attenuation above 40 MeV in the first few seconds of the burst. This power-law component transiti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.10605v2-abstract-full').style.display = 'inline'; document.getElementById('1909.10605v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.10605v2-abstract-full" style="display: none;"> We report on the observations of gamma-ray burst (GRB) 190114C by the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory. The early-time observations reveal multiple emission components that evolve independently, with a delayed power-law component that exhibits significant spectral attenuation above 40 MeV in the first few seconds of the burst. This power-law component transitions to a harder spectrum that is consistent with the afterglow emission observed at later times. This afterglow component is clearly identifiable in the GBM and BAT light curves as a slowly fading emission component on which the rest of the prompt emission is superimposed. As a result, we are able to constrain the transition from internal shock to external shock dominated emission. We find that the temporal and spectral evolution of the broadband afterglow emission can be well modeled as synchrotron emission from a forward shock propagating into a wind-like circumstellar environment and find that high-energy photons observed by Fermi LAT are in tension with the theoretical maximum energy that can be achieved through synchrotron emission from a shock. These violations of the maximum synchrotron energy are further compounded by the detection of very high energy (VHE) emission above 300 GeV by MAGIC concurrent with our observations. We conclude that the observations of VHE photons from GRB 190114C necessitates either an additional emission mechanism at very high energies that is hidden in the synchrotron component in the LAT energy range, an acceleration mechanism that imparts energy to the particles at a rate that is faster than the electron synchrotron energy loss rate, or revisions of the fundamental assumptions used in estimating the maximum photon energy attainable through the synchrotron process. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.10605v2-abstract-full').style.display = 'none'; document.getElementById('1909.10605v2-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 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 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">24 pages, 9 figures, Accepted to 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/1901.03982">arXiv:1901.03982</a> <span> [<a href="https://arxiv.org/pdf/1901.03982">pdf</a>, <a href="https://arxiv.org/format/1901.03982">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/stz089">10.1093/mnras/stz089 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> MAGIC and Fermi-LAT gamma-ray results on unassociated HAWC sources </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=Baack%2C+D">D. Baack</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=Berse%2C+R+C">R. Ch. Berse</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=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=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=Ceribella%2C+G">G. Ceribella</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> , et al. (318 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="1901.03982v1-abstract-short" style="display: inline;"> The HAWC Collaboration released the 2HWC catalog of TeV sources, in which 19 show no association with any known high-energy (HE; E > 10 GeV) or very-high-energy (VHE; E > 300 GeV) sources. This catalog motivated follow-up studies by both the MAGIC and Fermi-LAT observatories with the aim of investigating gamma-ray emission over a broad energy band. In this paper, we report the results from the fir… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1901.03982v1-abstract-full').style.display = 'inline'; document.getElementById('1901.03982v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1901.03982v1-abstract-full" style="display: none;"> The HAWC Collaboration released the 2HWC catalog of TeV sources, in which 19 show no association with any known high-energy (HE; E > 10 GeV) or very-high-energy (VHE; E > 300 GeV) sources. This catalog motivated follow-up studies by both the MAGIC and Fermi-LAT observatories with the aim of investigating gamma-ray emission over a broad energy band. In this paper, we report the results from the first joint work between HAWC, MAGIC and Fermi-LAT on three unassociated HAWC sources: 2HWC J2006+341, 2HWC J1907+084* and 2HWC J1852+013*. Although no significant detection was found in the HE and VHE regimes, this investigation shows that a minimum 1 degree extension (at 95% confidence level) and harder spectrum in the GeV than the one extrapolated from HAWC results are required in the case of 2HWC J1852+013*, while a simply minimum extension of 0.16 degrees (at 95% confidence level) can already explain the scenario proposed by HAWC for the remaining sources. Moreover, the hypothesis that these sources are pulsar wind nebulae is also investigated in detail. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1901.03982v1-abstract-full').style.display = 'none'; document.getElementById('1901.03982v1-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> 13 January, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">12 pages, 3 figures. Accepted for publication in MNRAS</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 485, Issue 1, May 2019, Pages 356-366 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1812.06681">arXiv:1812.06681</a> <span> [<a href="https://arxiv.org/pdf/1812.06681">pdf</a>, <a href="https://arxiv.org/format/1812.06681">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> </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/10.1051/0004-6361/201834555">10.1051/0004-6361/201834555 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Extending the Event-weighted Pulsation Search to Very Faint Gamma-ray Sources </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a> </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="1812.06681v1-abstract-short" style="display: inline;"> Because of the relatively broad angular resolution of current gamma-ray instruments in the MeV-GeV energy range, the photons of a given source are mixed with those coming from nearby sources or diffuse background. This source confusion seriously hampers the search for pulsation from faint sources. Statistical tests for pulsation can be made significantly more sensitive when the probability that a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.06681v1-abstract-full').style.display = 'inline'; document.getElementById('1812.06681v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1812.06681v1-abstract-full" style="display: none;"> Because of the relatively broad angular resolution of current gamma-ray instruments in the MeV-GeV energy range, the photons of a given source are mixed with those coming from nearby sources or diffuse background. This source confusion seriously hampers the search for pulsation from faint sources. Statistical tests for pulsation can be made significantly more sensitive when the probability that a photon comes from the pulsar is used as a weight. However, the computation of this probability requires knowing the spectral model of all sources in the region of interest, including the pulsar itself. This is not possible for very faint pulsars that are not detected as gamma-ray sources or whose spectrum is not measured precisely enough. Extending the event-weighted pulsation search to such very faint gamma-ray sources would allow improving our knowledge of the gamma-ray pulsar population. We present two methods that overcome this limitation by scanning the spectral parameter space, while minimizing the number of trials. The first one approximates the source/background ratio yielding a simple estimate of the weight while the second one makes use of the full spatial and spectral information of the region of interest around the pulsar. We test these new methods on a sample of 144 gamma-ray pulsars already detected by the Fermi Large Area Telescope data. Both methods detect pulsation from all pulsars of the sample, including the ones for which no significant phase-averaged gamma-ray emission is detected. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.06681v1-abstract-full').style.display = 'none'; document.getElementById('1812.06681v1-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 December, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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 in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 622, A108 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1812.02079">arXiv:1812.02079</a> <span> [<a href="https://arxiv.org/pdf/1812.02079">pdf</a>, <a href="https://arxiv.org/format/1812.02079">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</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/10.1103/PhysRevLett.121.241101">10.1103/PhysRevLett.121.241101 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unresolved Gamma-Ray Sky through its Angular Power Spectrum </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Burns%2C+E">E. Burns</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R. Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S">S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">G. Chiaro</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Costantin%2C+D">D. Costantin</a>, <a href="/search/astro-ph?searchtype=author&query=Cuoco%2C+A">A. Cuoco</a> , et al. (85 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="1812.02079v4-abstract-short" style="display: inline;"> The gamma-ray sky has been observed with unprecedented accuracy in the last decade by the Fermi large area telescope (LAT), allowing us to resolve and understand the high-energy Universe. The nature of the remaining unresolved emission (unresolved gamma-ray background, UGRB) below the LAT source detection threshold can be uncovered by characterizing the amplitude and angular scale of the UGRB fluc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.02079v4-abstract-full').style.display = 'inline'; document.getElementById('1812.02079v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1812.02079v4-abstract-full" style="display: none;"> The gamma-ray sky has been observed with unprecedented accuracy in the last decade by the Fermi large area telescope (LAT), allowing us to resolve and understand the high-energy Universe. The nature of the remaining unresolved emission (unresolved gamma-ray background, UGRB) below the LAT source detection threshold can be uncovered by characterizing the amplitude and angular scale of the UGRB fluctuation field. This work presents a measurement of the UGRB autocorrelation angular power spectrum based on eight years of Fermi LAT Pass 8 data products. The analysis is designed to be robust against contamination from resolved sources and noise systematics. The sensitivity to subthreshold sources is greatly enhanced with respect to previous measurements. We find evidence (with $\sim$3.7$蟽$ significance) that the scenario in which two classes of sources contribute to the UGRB signal is favored over a single class. A double power law with exponential cutoff can explain the anisotropy energy spectrum well, with photon indices of the two populations being 2.55 $\pm$ 0.23 and 1.86 $\pm$ 0.15. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.02079v4-abstract-full').style.display = 'none'; document.getElementById('1812.02079v4-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 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 December, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">8 + 12 (SOM) pages, Contact author: Michela Negro (michela.negro@to.infn.it). (Typos in Tab. VII in previous versions)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 121, 241101 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1812.00719">arXiv:1812.00719</a> <span> [<a href="https://arxiv.org/pdf/1812.00719">pdf</a>, <a href="https://arxiv.org/ps/1812.00719">ps</a>, <a href="https://arxiv.org/format/1812.00719">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/aaf57d">10.3847/1538-4357/aaf57d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Searching a Thousand Radio Pulsars for Gamma-ray Emission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smith%2C+D+A">David A. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">Philippe Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">Isma毛l Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+A+D">Andrew D. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Camilo%2C+F">Fernando Camilo</a>, <a href="/search/astro-ph?searchtype=author&query=Dai%2C+S">Shi Dai</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">Lucas Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+T+J">Tyrel J. Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+S">Simon Johnston</a>, <a href="/search/astro-ph?searchtype=author&query=Keith%2C+M+J">Michael J. Keith</a>, <a href="/search/astro-ph?searchtype=author&query=Kerr%2C+M">Matthew Kerr</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">Michael Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lyne%2C+A+G">Andrew G. Lyne</a>, <a href="/search/astro-ph?searchtype=author&query=Manchester%2C+R+N">Richard N. Manchester</a>, <a href="/search/astro-ph?searchtype=author&query=Shannon%2C+R">Ryan Shannon</a>, <a href="/search/astro-ph?searchtype=author&query=Sobey%2C+C">Charlotte Sobey</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">Benjamin W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Weltevrede%2C+P">Patrick Weltevrede</a> </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="1812.00719v1-abstract-short" style="display: inline;"> Identifying as many gamma-ray pulsars as possible in the Fermi Large Area Telescope (LAT) data helps test pulsar emission models by comparing predicted and observed properties for a large, varied sample with as little selection bias as possible. It also improves extrapolations from the observed population to estimate the contribution of unresolved pulsars to the diffuse gamma-ray emission. We use… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.00719v1-abstract-full').style.display = 'inline'; document.getElementById('1812.00719v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1812.00719v1-abstract-full" style="display: none;"> Identifying as many gamma-ray pulsars as possible in the Fermi Large Area Telescope (LAT) data helps test pulsar emission models by comparing predicted and observed properties for a large, varied sample with as little selection bias as possible. It also improves extrapolations from the observed population to estimate the contribution of unresolved pulsars to the diffuse gamma-ray emission. We use a recently developed method to determine the probability that a given gamma-ray photon comes from a known position in the sky, convolving the photon's energy with the LAT's energy-dependent point-spread-function (PSF), without the need for an accurate spatial and spectral model of the gamma-ray sky around the pulsar. The method is simple and fast and, importantly, provides probabilities, or _weights_, for gamma rays from pulsars too faint for phase-integrated detection. We applied the method to over a thousand pulsars for which we obtained rotation ephemerides from radio observations, and discovered gamma-ray pulsations from 16 pulsars, 12 young and 4 recycled. PSR J2208+4056 has spindown power Edot = 8e32 erg/s, about three times lower than the previous observed gamma-ray emission "deathline". PSRs J2208+4056 and J1816-0755 have radio interpulses, constraining their geometry and perhaps enhancing their gamma-ray luminosity. We discuss whether the deathline is an artifact of selection bias due to the pulsar distance. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.00719v1-abstract-full').style.display = 'none'; document.getElementById('1812.00719v1-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 December, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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 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/1810.11394">arXiv:1810.11394</a> <span> [<a href="https://arxiv.org/pdf/1810.11394">pdf</a>, <a href="https://arxiv.org/format/1810.11394">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> <p class="title is-5 mathjax"> Fermi-LAT improved Pass~8 event selection </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Burnett%2C+T+H">T. H. Burnett</a>, <a href="/search/astro-ph?searchtype=author&query=Digel%2C+S+W">S. W. Digel</a>, <a href="/search/astro-ph?searchtype=author&query=Johannesson%2C+G">G. Johannesson</a>, <a href="/search/astro-ph?searchtype=author&query=Omodei%2C+N">N. Omodei</a>, <a href="/search/astro-ph?searchtype=author&query=Wood%2C+M">M. Wood</a> </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="1810.11394v1-abstract-short" style="display: inline;"> The current version of the Fermi Large Area Telescope data (P8R2) has been publicly available since June 2015, with the caveat that the residual background of all event classes, except ULTRACLEANVETO, was not fully isotropic: it was enhanced by a factor ~2 at 1-3 GeV within ~20 deg of the Ecliptic compared to the poles. By investigating the residual background using data only, we were able to find… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.11394v1-abstract-full').style.display = 'inline'; document.getElementById('1810.11394v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1810.11394v1-abstract-full" style="display: none;"> The current version of the Fermi Large Area Telescope data (P8R2) has been publicly available since June 2015, with the caveat that the residual background of all event classes, except ULTRACLEANVETO, was not fully isotropic: it was enhanced by a factor ~2 at 1-3 GeV within ~20 deg of the Ecliptic compared to the poles. By investigating the residual background using data only, we were able to find two sources of residual background: one due to non-interacting heavy ions and one due to cosmic-ray electrons leaking through the ribbons of the Anti-Coincidence Detector, the latter source being responsible for the background anisotropy. A set of simple cuts allows us to reject these events while losing less than 1% of the SOURCE class acceptance. This new selection has been used to produce a new version of the LAT data (P8R3). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.11394v1-abstract-full').style.display = 'none'; document.getElementById('1810.11394v1-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 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">This paper corresponds to a poster that was presented at the 8th International Fermi Symposium, October 14-19 2018, Baltimore</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1808.10423">arXiv:1808.10423</a> <span> [<a href="https://arxiv.org/pdf/1808.10423">pdf</a>, <a href="https://arxiv.org/ps/1808.10423">ps</a>, <a href="https://arxiv.org/format/1808.10423">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/aade4e">10.3847/1538-4357/aade4e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> VERITAS and Fermi-LAT observations of new HAWC sources </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=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=Chromey%2C+A+J">A. J. Chromey</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=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>, <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. (259 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="1808.10423v1-abstract-short" style="display: inline;"> The HAWC (High Altitude Water Cherenkov) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100~GeV) gamma-ray sources based on 507 days of observation. Among these, there are nineteen sources that are not associated with previously known TeV sources. We have studied fourteen of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detect… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.10423v1-abstract-full').style.display = 'inline'; document.getElementById('1808.10423v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.10423v1-abstract-full" style="display: none;"> The HAWC (High Altitude Water Cherenkov) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100~GeV) gamma-ray sources based on 507 days of observation. Among these, there are nineteen sources that are not associated with previously known TeV sources. We have studied fourteen of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1~TeV-30~TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected fourteen new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected GeV gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.10423v1-abstract-full').style.display = 'none'; document.getElementById('1808.10423v1-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 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">Accepted for publication in the ApJ, Corresponding author: Nahee Park (VERITAS Collaboration), John W. Hewitt (Fermi-LAT Collaboration), Ignacio Taboada (HAWC Collaboration), 30 pages, 12 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 866 (2018) no.1, 24 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1706.06483">arXiv:1706.06483</a> <span> [<a href="https://arxiv.org/pdf/1706.06483">pdf</a>, <a href="https://arxiv.org/format/1706.06483">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 Physics - Experiment">hep-ex</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/10.1016/j.astropartphys.2017.10.008">10.1016/j.astropartphys.2017.10.008 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Performance measurement of HARPO: a Time Projection Chamber as a gamma-ray telescope and polarimeter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gros%2C+P">P. Gros</a>, <a href="/search/astro-ph?searchtype=author&query=Amano%2C+S">S. Amano</a>, <a href="/search/astro-ph?searchtype=author&query=Atti%C3%A9%2C+D">D. Atti茅</a>, <a href="/search/astro-ph?searchtype=author&query=Baron%2C+P">P. Baron</a>, <a href="/search/astro-ph?searchtype=author&query=Baudin%2C+D">D. Baudin</a>, <a href="/search/astro-ph?searchtype=author&query=Bernard%2C+D">D. Bernard</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Calvet%2C+D">D. Calvet</a>, <a href="/search/astro-ph?searchtype=author&query=Colas%2C+P">P. Colas</a>, <a href="/search/astro-ph?searchtype=author&query=Dat%C3%A9%2C+S">S. Dat茅</a>, <a href="/search/astro-ph?searchtype=author&query=Delbart%2C+A">A. Delbart</a>, <a href="/search/astro-ph?searchtype=author&query=Frotin%2C+M">M. Frotin</a>, <a href="/search/astro-ph?searchtype=author&query=Geerebaert%2C+Y">Y. Geerebaert</a>, <a href="/search/astro-ph?searchtype=author&query=Giebels%2C+B">B. Giebels</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B6tz%2C+D">D. G枚tz</a>, <a href="/search/astro-ph?searchtype=author&query=Hashimoto%2C+S">S. Hashimoto</a>, <a href="/search/astro-ph?searchtype=author&query=Horan%2C+D">D. Horan</a>, <a href="/search/astro-ph?searchtype=author&query=Kotaka%2C+T">T. Kotaka</a>, <a href="/search/astro-ph?searchtype=author&query=Louzir%2C+M">M. Louzir</a>, <a href="/search/astro-ph?searchtype=author&query=Magniette%2C+F">F. Magniette</a>, <a href="/search/astro-ph?searchtype=author&query=Minamiyama%2C+Y">Y. Minamiyama</a>, <a href="/search/astro-ph?searchtype=author&query=Miyamoto%2C+S">S. Miyamoto</a>, <a href="/search/astro-ph?searchtype=author&query=Ohkuma%2C+H">H. Ohkuma</a>, <a href="/search/astro-ph?searchtype=author&query=Poilleux%2C+P">P. Poilleux</a>, <a href="/search/astro-ph?searchtype=author&query=Semeniouk%2C+I">I. Semeniouk</a> , et al. (5 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="1706.06483v2-abstract-short" style="display: inline;"> We analyse the performance of a gas time projection chamber (TPC) as a high-performance gamma-ray telescope and polarimeter in the e$^+$e$^-$ pair creation regime. We use data collected at a gamma-ray beam of known polarisation. The TPC provides two orthogonal projections $(x,z)$ and $(y,z)$ of the tracks induced by each conversion in the gas volume. We use a simple vertex finder in which vertices… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.06483v2-abstract-full').style.display = 'inline'; document.getElementById('1706.06483v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1706.06483v2-abstract-full" style="display: none;"> We analyse the performance of a gas time projection chamber (TPC) as a high-performance gamma-ray telescope and polarimeter in the e$^+$e$^-$ pair creation regime. We use data collected at a gamma-ray beam of known polarisation. The TPC provides two orthogonal projections $(x,z)$ and $(y,z)$ of the tracks induced by each conversion in the gas volume. We use a simple vertex finder in which vertices and pseudo-tracks exiting from them are identified. We study the various contributions to the single-photon angular resolution using Monte Carlo simulations and compare them with the experimental data and find that they are in excellent agreement. The distribution of the azimutal angle of pair conversions shows a bias due to the non-cylindrical-symmetric structure of the detector. This bias would average out for a long duration exposure on a space mission, but for this pencil-beam characterisation we have ensured its accurate simulation by a double systematics control scheme, data taking with the detector rotated at several angles with respect to the beam polarisation direction and systematics control with a non-polarised beam. We measure, for the first time, the polarisation asymmetry of a linearly polarised gamma-ray beam in the low energy pair creation regime. This sub-GeV energy range is critical for cosmic sources as their spectra are power laws which fall quickly as a function of increasing energy. This work could pave the way to extending polarised gamma-ray astronomy beyond the MeV energy regime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.06483v2-abstract-full').style.display = 'none'; document.getElementById('1706.06483v2-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 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 June, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">Submitted to Astroparticle Physics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1704.07195">arXiv:1704.07195</a> <span> [<a href="https://arxiv.org/pdf/1704.07195">pdf</a>, <a href="https://arxiv.org/format/1704.07195">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/10.1103/PhysRevD.95.082007">10.1103/PhysRevD.95.082007 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Cosmic-ray electron+positron spectrum from 7 GeV to 2 TeV with the Fermi Large Area Telescope </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Collaboration%2C+F">Fermi-LAT Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=%3A"> :</a>, <a href="/search/astro-ph?searchtype=author&query=Abdollahi%2C+S">S. Abdollahi</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Atwood%2C+W+B">W. B. Atwood</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Brandt%2C+T+J">T. J. Brandt</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R. Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+D">D. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">C. Cecchi</a>, <a href="/search/astro-ph?searchtype=author&query=Chekhtman%2C+A">A. Chekhtman</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen-Tanugi%2C+J">J. Cohen-Tanugi</a> , et al. (76 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="1704.07195v1-abstract-short" style="display: inline;"> We present a measurement of the cosmic-ray electron+positron spectrum between 7 GeV and 2 TeV performed with almost seven years of data collected with the Fermi Large Area Telescope. We find that the spectrum is well fit by a broken power law with a break energy at about 50 GeV. Above 50 GeV, the spectrum is well described by a single power law with a spectral index of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.07195v1-abstract-full').style.display = 'inline'; document.getElementById('1704.07195v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1704.07195v1-abstract-full" style="display: none;"> We present a measurement of the cosmic-ray electron+positron spectrum between 7 GeV and 2 TeV performed with almost seven years of data collected with the Fermi Large Area Telescope. We find that the spectrum is well fit by a broken power law with a break energy at about 50 GeV. Above 50 GeV, the spectrum is well described by a single power law with a spectral index of $3.07 \pm 0.02 \; (\text{stat+syst}) \pm 0.04 \; (\text{energy measurement})$. An exponential cutoff lower than 1.8 TeV is excluded at 95\% CL. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.07195v1-abstract-full').style.display = 'none'; document.getElementById('1704.07195v1-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 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. D 95, 082007 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.00577">arXiv:1702.00577</a> <span> [<a href="https://arxiv.org/pdf/1702.00577">pdf</a>, <a href="https://arxiv.org/ps/1702.00577">ps</a>, <a href="https://arxiv.org/format/1702.00577">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> </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/10.3847/1538-4357/835/2/219">10.3847/1538-4357/835/2/219 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fermi-LAT Observations of High-energy Behind-the-limb Solar Flares </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Allafort%2C+A">A. Allafort</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">C. Cecchi</a>, <a href="/search/astro-ph?searchtype=author&query=Charles%2C+E">E. Charles</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Costanza%2C+F">F. Costanza</a>, <a href="/search/astro-ph?searchtype=author&query=Cutini%2C+S">S. Cutini</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Ammando%2C+F">F. D'Ammando</a>, <a href="/search/astro-ph?searchtype=author&query=de+Palma%2C+F">F. de Palma</a>, <a href="/search/astro-ph?searchtype=author&query=Desiante%2C+R">R. Desiante</a>, <a href="/search/astro-ph?searchtype=author&query=Digel%2C+S+W">S. W. Digel</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="1702.00577v1-abstract-short" style="display: inline;"> We report on the Fermi-LAT detection of high-energy emission from the behind-the-limb (BTL) solar flares that occurred on 2013 October 11, and 2014 January 6 and September 1. The Fermi-LAT observations are associated with flares from active regions originating behind both the eastern and western limbs, as determined by STEREO. All three flares are associated with very fast coronal mass ejections (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.00577v1-abstract-full').style.display = 'inline'; document.getElementById('1702.00577v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.00577v1-abstract-full" style="display: none;"> We report on the Fermi-LAT detection of high-energy emission from the behind-the-limb (BTL) solar flares that occurred on 2013 October 11, and 2014 January 6 and September 1. The Fermi-LAT observations are associated with flares from active regions originating behind both the eastern and western limbs, as determined by STEREO. All three flares are associated with very fast coronal mass ejections (CMEs) and strong solar energetic particle events. We present updated localizations of the >100 MeV photon emission, hard X-ray (HXR)and EUV images, and broadband spectra from 10 keV to 10 GeV, as well as microwave spectra. We also provide a comparison of the BTL flares detected by Fermi-LAT with three on-disk flares and present a study of some of the significant quantities of these flares as an attempt to better understand the acceleration mechanisms at work during these occulted flares. We interpret the HXR emission to be due to electron bremsstrahlung from a coronal thin-target loop top with the accelerated electron spectra steepening at semirelativistic energies. The >100 MeV gamma-rays are best described by a pion-decay model resulting from the interaction of protons (and other ions) in a thick-target photospheric source. The protons are believed to have been accelerated (to energies >10 GeV) in the CME environment and precipitate down to the photosphere from the downstream side of the CME shock and landed on the front side of the Sun, away from the original flare site and the HXR emission. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.00577v1-abstract-full').style.display = 'none'; document.getElementById('1702.00577v1-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, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">13 pages, 14 figures published on ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 835, 219, 1 February 2017 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.00476">arXiv:1702.00476</a> <span> [<a href="https://arxiv.org/pdf/1702.00476">pdf</a>, <a href="https://arxiv.org/format/1702.00476">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/aa775a">10.3847/1538-4357/aa775a <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for extended sources in the Galactic Plane using 6 years of Fermi-Large Area Telescope Pass 8 data above 10 GeV </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+Fermi+LAT+Collaboration"> The Fermi LAT Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Brandt%2C+T+J">T. J. Brandt</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+D">D. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">C. Cecchi</a>, <a href="/search/astro-ph?searchtype=author&query=Charles%2C+E">E. Charles</a>, <a href="/search/astro-ph?searchtype=author&query=Chekhtman%2C+A">A. Chekhtman</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+C+C">C. C. Cheung</a> , et al. (95 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="1702.00476v2-abstract-short" style="display: inline;"> The spatial extension of a gamma-ray source is an essential ingredient to determine its spectral properties as well as its potential multi-wavelength counterpart. The capability to spatially resolve gamma-ray sources is greatly improved by the newly delivered Fermi-Large Area Telescope (LAT) Pass 8 event-level analysis which provides a greater acceptance and an improved point spread function, two… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.00476v2-abstract-full').style.display = 'inline'; document.getElementById('1702.00476v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.00476v2-abstract-full" style="display: none;"> The spatial extension of a gamma-ray source is an essential ingredient to determine its spectral properties as well as its potential multi-wavelength counterpart. The capability to spatially resolve gamma-ray sources is greatly improved by the newly delivered Fermi-Large Area Telescope (LAT) Pass 8 event-level analysis which provides a greater acceptance and an improved point spread function, two crucial factors for the detection of extended sources. Here, we present a complete search for extended sources located within 7 degrees from the Galactic plane, using 6 years of LAT data above 10 GeV. We find 46 extended sources and provide their morphological and spectral characteristics. This constitutes the first catalog of hard LAT extended sources, named the Fermi Galactic Extended Source Catalog, which allows a thorough study of the properties of the Galactic plane in the sub-TeV domain. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.00476v2-abstract-full').style.display = 'none'; document.getElementById('1702.00476v2-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 April, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 February, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">33 pages, 22 figures & 3 tables. Published by The Astrophysical Journal. Available on the Fermi Science Support Center (FSSC) together with the 3FHL catalog</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1612.03165">arXiv:1612.03165</a> <span> [<a href="https://arxiv.org/pdf/1612.03165">pdf</a>, <a href="https://arxiv.org/format/1612.03165">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/aa8092">10.3847/1538-4357/aa8092 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The second catalog of flaring gamma-ray sources from the Fermi All-sky Variability Analysis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abdollahi%2C+S">S. Abdollahi</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+A">A. Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J+B">J. Becerra Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">C. Cecchi</a>, <a href="/search/astro-ph?searchtype=author&query=Chekhtman%2C+A">A. Chekhtman</a> , et al. (102 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="1612.03165v3-abstract-short" style="display: inline;"> We present the second catalog of flaring gamma-ray sources (2FAV) detected with the Fermi All-sky Variability Analysis (FAVA), a tool that blindly searches for transients over the entire sky observed by the Large Area Telescope (LAT) on board the \textit{Fermi} Gamma-ray Space Telescope. With respect to the first FAVA catalog, this catalog benefits from a larger data set, the latest LAT data relea… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.03165v3-abstract-full').style.display = 'inline'; document.getElementById('1612.03165v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1612.03165v3-abstract-full" style="display: none;"> We present the second catalog of flaring gamma-ray sources (2FAV) detected with the Fermi All-sky Variability Analysis (FAVA), a tool that blindly searches for transients over the entire sky observed by the Large Area Telescope (LAT) on board the \textit{Fermi} Gamma-ray Space Telescope. With respect to the first FAVA catalog, this catalog benefits from a larger data set, the latest LAT data release (Pass 8), as well as from an improved analysis that includes likelihood techniques for a more precise localization of the transients. Applying this analysis on the first 7.4 years of \textit{Fermi} observations, and in two separate energy bands 0.1$-$0.8 GeV and 0.8$-$300 GeV, a total of 4547 flares has been detected with a significance greater than $6蟽$ (before trials), on the time scale of one week. Through spatial clustering of these flares, 518 variable gamma-ray sources are identified. Likely counterparts, based on positional coincidence, have been found for 441 sources, mostly among the blazar class of active galactic nuclei. For 77 2FAV sources, no likely gamma-ray counterpart has been found. For each source in the catalog, we provide the time, location, and spectrum of each flaring episode. Studying the spectra of the flares, we observe a harder-when-brighter behavior for flares associated with blazars, with the exception of BL Lac flares detected in the low-energy band. The photon indexes of the flares are never significantly smaller than 1.5. For a leptonic model, and under the assumption of isotropy, this limit suggests that the spectrum of the freshly accelerated electrons is never harder than $p\sim$2. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.03165v3-abstract-full').style.display = 'none'; document.getElementById('1612.03165v3-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 September, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 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">Accepted for publication by The Astrophysical Journal Supplement. Online analysis results available at http://fermi.gsfc.nasa.gov/ssc/data/access/lat/FAVA/index.php . Corresponding authors: M. Giomi, R. Buehler, D. Kocevski, and M. Ajello</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1612.01843">arXiv:1612.01843</a> <span> [<a href="https://arxiv.org/pdf/1612.01843">pdf</a>, <a href="https://arxiv.org/format/1612.01843">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="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/10.1051/0004-6361/201629427">10.1051/0004-6361/201629427 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gamma-ray blazar spectra with H.E.S.S. II mono analysis: the case of PKS 2155-304 and PG 1553+113 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Collaboration%2C+H+E+S+S">H. E. S. S. Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=%3A"> :</a>, <a href="/search/astro-ph?searchtype=author&query=Abdalla%2C+H">H. Abdalla</a>, <a href="/search/astro-ph?searchtype=author&query=Abramowski%2C+A">A. Abramowski</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=Benkhali%2C+F+A">F. Ait Benkhali</a>, <a href="/search/astro-ph?searchtype=author&query=Akhperjanian%2C+A+G">A. G. Akhperjanian</a>, <a href="/search/astro-ph?searchtype=author&query=Andersson%2C+T">T. Andersson</a>, <a href="/search/astro-ph?searchtype=author&query=Ang%C3%BCner%2C+E+O">E. O. Ang眉ner</a>, <a href="/search/astro-ph?searchtype=author&query=Arrieta%2C+M">M. Arrieta</a>, <a href="/search/astro-ph?searchtype=author&query=Aubert%2C+P">P. Aubert</a>, <a href="/search/astro-ph?searchtype=author&query=Backes%2C+M">M. Backes</a>, <a href="/search/astro-ph?searchtype=author&query=Balzer%2C+A">A. Balzer</a>, <a href="/search/astro-ph?searchtype=author&query=Barnard%2C+M">M. Barnard</a>, <a href="/search/astro-ph?searchtype=author&query=Becherini%2C+Y">Y. Becherini</a>, <a href="/search/astro-ph?searchtype=author&query=Tjus%2C+J+B">J. Becker Tjus</a>, <a href="/search/astro-ph?searchtype=author&query=Berge%2C+D">D. Berge</a>, <a href="/search/astro-ph?searchtype=author&query=Bernhard%2C+S">S. Bernhard</a>, <a href="/search/astro-ph?searchtype=author&query=Bernl%C3%B6hr%2C+K">K. Bernl枚hr</a>, <a href="/search/astro-ph?searchtype=author&query=Blackwell%2C+R">R. Blackwell</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=Boisson%2C+C">C. Boisson</a>, <a href="/search/astro-ph?searchtype=author&query=Bolmont%2C+J">J. Bolmont</a>, <a href="/search/astro-ph?searchtype=author&query=Bordas%2C+P">P. Bordas</a>, <a href="/search/astro-ph?searchtype=author&query=Brun%2C+F">F. Brun</a> , et al. (311 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="1612.01843v1-abstract-short" style="display: inline;"> The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV. Such an extension of the instrument's energy range is particularly beneficial for studies of Active Galactic Nuclei with soft sp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.01843v1-abstract-full').style.display = 'inline'; document.getElementById('1612.01843v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1612.01843v1-abstract-full" style="display: none;"> The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV. Such an extension of the instrument's energy range is particularly beneficial for studies of Active Galactic Nuclei with soft spectra, as expected for those at a redshift > 0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0.116) and PG 1553+113 (0.43 < z < 0.58) are among the brightest objects in the gamma-ray sky, both showing clear signatures of gamma-ray absorption at E > 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Multiple observational campaigns of PKS 2155-304 and PG 1553+113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument. A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters. The energy spectra of PKS 2155-304 and PG 1553+113 were reconstructed down to energies of 80 GeV for PKS 2155-304, which transits near zenith, and 110 GeV for the more northern PG 1553+113. The measured spectra, well fitted in both cases by a log-parabola spectral model (with a 5.0 sigma statistical preference for non-zero curvature for PKS 2155-304 and 4.5 sigma for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the observed spectra of both sources at E ~ 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi-LAT spectrum of PKS 2155-304 was found to show significant curvature. For PG 1553+113, however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.01843v1-abstract-full').style.display = 'none'; document.getElementById('1612.01843v1-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 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">13 pages, 9 figures, accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 600, A89 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1606.09417">arXiv:1606.09417</a> <span> [<a href="https://arxiv.org/pdf/1606.09417">pdf</a>, <a href="https://arxiv.org/format/1606.09417">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="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/10.1117/12.2231856">10.1117/12.2231856 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First measurement of polarisation asymmetry of a gamma-ray beam between 1.74 to 74 MeV with the HARPO TPC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gros%2C+P">Philippe Gros</a>, <a href="/search/astro-ph?searchtype=author&query=Amano%2C+S">Sho Amano</a>, <a href="/search/astro-ph?searchtype=author&query=Atti%C3%A9%2C+D">David Atti茅</a>, <a href="/search/astro-ph?searchtype=author&query=Bernard%2C+D">Denis Bernard</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">Philippe Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Calvet%2C+D">Denis Calvet</a>, <a href="/search/astro-ph?searchtype=author&query=Colas%2C+P">Paul Colas</a>, <a href="/search/astro-ph?searchtype=author&query=Dat%C3%A9%2C+S">Schin Dat茅</a>, <a href="/search/astro-ph?searchtype=author&query=Delbart%2C+A">Alain Delbart</a>, <a href="/search/astro-ph?searchtype=author&query=Frotin%2C+M">Mickael Frotin</a>, <a href="/search/astro-ph?searchtype=author&query=Geerebaert%2C+Y">Yannick Geerebaert</a>, <a href="/search/astro-ph?searchtype=author&query=Giebels%2C+B">Berrie Giebels</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B6tz%2C+D">Diego G枚tz</a>, <a href="/search/astro-ph?searchtype=author&query=Hashimoto%2C+S">S. Hashimoto</a>, <a href="/search/astro-ph?searchtype=author&query=Horan%2C+D">Deirdr Horan</a>, <a href="/search/astro-ph?searchtype=author&query=Kotaka%2C+T">T. Kotaka</a>, <a href="/search/astro-ph?searchtype=author&query=Louzir%2C+M">Marc Louzir</a>, <a href="/search/astro-ph?searchtype=author&query=Minamiyama%2C+Y">Y. Minamiyama</a>, <a href="/search/astro-ph?searchtype=author&query=Miyamoto%2C+S">Shuji Miyamoto</a>, <a href="/search/astro-ph?searchtype=author&query=Ohkuma%2C+H">H. Ohkuma</a>, <a href="/search/astro-ph?searchtype=author&query=Poilleux%2C+P">Patrick Poilleux</a>, <a href="/search/astro-ph?searchtype=author&query=Semeniouk%2C+I">Igor Semeniouk</a>, <a href="/search/astro-ph?searchtype=author&query=Sizun%2C+P">Patrick Sizun</a>, <a href="/search/astro-ph?searchtype=author&query=Takemoto%2C+A">A. Takemoto</a>, <a href="/search/astro-ph?searchtype=author&query=Yamaguchi%2C+M">M. Yamaguchi</a> , et al. (1 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="1606.09417v1-abstract-short" style="display: inline;"> Current $纬$-ray telescopes suffer from a gap in sensitivity in the energy range between 100keV and 100MeV, and no polarisation measurement has ever been done on cosmic sources above 1MeV. Past and present e$^+$e$^-$ pair telescopes are limited at lower energies by the multiple scattering of electrons in passive tungsten converter plates. This results in low angular resolution, and, consequently, a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.09417v1-abstract-full').style.display = 'inline'; document.getElementById('1606.09417v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1606.09417v1-abstract-full" style="display: none;"> Current $纬$-ray telescopes suffer from a gap in sensitivity in the energy range between 100keV and 100MeV, and no polarisation measurement has ever been done on cosmic sources above 1MeV. Past and present e$^+$e$^-$ pair telescopes are limited at lower energies by the multiple scattering of electrons in passive tungsten converter plates. This results in low angular resolution, and, consequently, a drop in sensitivity to point sources below 1GeV. The polarisation information, which is carried by the azimuthal angle of the conversion plane, is lost for the same reasons. HARPO (Hermetic ARgon POlarimeter) is an R\&D program to characterise the operation of a gaseous detector (a Time Projection Chamber or TPC) as a high angular-resolution and sensitivity telescope and polarimeter for $纬$ rays from cosmic sources. It represents a first step towards a future space instrument in the MeV-GeV range. We built and characterised a 30cm cubic demonstrator [SPIE 91441M], and put it in a polarised $纬$-ray beam at the NewSUBARU accelerator in Japan. Data were taken at photon energies from 1.74MeV to 74MeV, and with different polarisation configurations. We describe the experimental setup in beam. We then describe the software we developed to reconstruct the photon conversion events, with special focus on low energies. We also describe the thorough simulation of the detector used to compare results. Finally we will present the performance of the detector as extracted from this analysis and preliminary measurements of the polarisation asymmetry. This beam-test qualification of a gas TPC prototype in a $纬$-ray beam could open the way to high-performance $纬$-ray astronomy and polarimetry in the MeV-GeV energy range in the near future. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.09417v1-abstract-full').style.display = 'none'; document.getElementById('1606.09417v1-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 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">SPIE Astronomical telescopes and instrumentation conference 2016</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1606.04901">arXiv:1606.04901</a> <span> [<a href="https://arxiv.org/pdf/1606.04901">pdf</a>, <a href="https://arxiv.org/format/1606.04901">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/10.3847/1538-4357/835/1/82">10.3847/1538-4357/835/1/82 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Searching the Gamma-ray Sky for Counterparts to Gravitational Wave Sources: Fermi GBM and LAT Observations of LVT151012 and GW151226 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Racusin%2C+J+L">J. L. Racusin</a>, <a href="/search/astro-ph?searchtype=author&query=Burns%2C+E">E. Burns</a>, <a href="/search/astro-ph?searchtype=author&query=Goldstein%2C+A">A. Goldstein</a>, <a href="/search/astro-ph?searchtype=author&query=Connaughton%2C+V">V. Connaughton</a>, <a href="/search/astro-ph?searchtype=author&query=Wilson-Hodge%2C+C+A">C. A. Wilson-Hodge</a>, <a href="/search/astro-ph?searchtype=author&query=Jenke%2C+P">P. Jenke</a>, <a href="/search/astro-ph?searchtype=author&query=Blackburn%2C+L">L. Blackburn</a>, <a href="/search/astro-ph?searchtype=author&query=Briggs%2C+M+S">M. S. Briggs</a>, <a href="/search/astro-ph?searchtype=author&query=Broida%2C+J">J. Broida</a>, <a href="/search/astro-ph?searchtype=author&query=Camp%2C+J">J. Camp</a>, <a href="/search/astro-ph?searchtype=author&query=Christensen%2C+N">N. Christensen</a>, <a href="/search/astro-ph?searchtype=author&query=Hui%2C+C+M">C. M. Hui</a>, <a href="/search/astro-ph?searchtype=author&query=Littenberg%2C+T">T. Littenberg</a>, <a href="/search/astro-ph?searchtype=author&query=Shawhan%2C+P">P. Shawhan</a>, <a href="/search/astro-ph?searchtype=author&query=Singer%2C+L">L. Singer</a>, <a href="/search/astro-ph?searchtype=author&query=Veitch%2C+J">J. Veitch</a>, <a href="/search/astro-ph?searchtype=author&query=Bhat%2C+P+N">P. N. Bhat</a>, <a href="/search/astro-ph?searchtype=author&query=Cleveland%2C+W">W. Cleveland</a>, <a href="/search/astro-ph?searchtype=author&query=Fitzpatrick%2C+G">G. Fitzpatrick</a>, <a href="/search/astro-ph?searchtype=author&query=Gibby%2C+M+H">M. H. Gibby</a>, <a href="/search/astro-ph?searchtype=author&query=von+Kienlin%2C+A">A. von Kienlin</a>, <a href="/search/astro-ph?searchtype=author&query=McBreen%2C+S">S. McBreen</a>, <a href="/search/astro-ph?searchtype=author&query=Mailyan%2C+B">B. Mailyan</a>, <a href="/search/astro-ph?searchtype=author&query=Meegan%2C+C+A">C. A. Meegan</a>, <a href="/search/astro-ph?searchtype=author&query=Paciesas%2C+W+S">W. S. Paciesas</a> , et al. (116 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="1606.04901v1-abstract-short" style="display: inline;"> We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candi- date LVT151012. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techn… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.04901v1-abstract-full').style.display = 'inline'; document.getElementById('1606.04901v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1606.04901v1-abstract-full" style="display: none;"> We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candi- date LVT151012. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for char- acterizing the upper limits across a large area of the sky. Due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, dif- ferences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.04901v1-abstract-full').style.display = 'none'; document.getElementById('1606.04901v1-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 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">27 pages, 1 table, 11 figures, Submitted to 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/1604.07864">arXiv:1604.07864</a> <span> [<a href="https://arxiv.org/pdf/1604.07864">pdf</a>, <a href="https://arxiv.org/ps/1604.07864">ps</a>, <a href="https://arxiv.org/format/1604.07864">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="General Relativity and Quantum Cosmology">gr-qc</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/10.3847/0067-0049/225/1/8">10.3847/0067-0049/225/1/8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Supplement: Localization and broadband follow-up of the gravitational-wave transient GW150914 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abbott%2C+B+P">B. P. Abbott</a>, <a href="/search/astro-ph?searchtype=author&query=Abbott%2C+R">R. Abbott</a>, <a href="/search/astro-ph?searchtype=author&query=Abbott%2C+T+D">T. D. Abbott</a>, <a href="/search/astro-ph?searchtype=author&query=Abernathy%2C+M+R">M. R. Abernathy</a>, <a href="/search/astro-ph?searchtype=author&query=Acernese%2C+F">F. Acernese</a>, <a href="/search/astro-ph?searchtype=author&query=Ackley%2C+K">K. Ackley</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+C">C. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+T">T. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Addesso%2C+P">P. Addesso</a>, <a href="/search/astro-ph?searchtype=author&query=Adhikari%2C+R+X">R. X. Adhikari</a>, <a href="/search/astro-ph?searchtype=author&query=Adya%2C+V+B">V. B. Adya</a>, <a href="/search/astro-ph?searchtype=author&query=Affeldt%2C+C">C. Affeldt</a>, <a href="/search/astro-ph?searchtype=author&query=Agathos%2C+M">M. Agathos</a>, <a href="/search/astro-ph?searchtype=author&query=Agatsuma%2C+K">K. Agatsuma</a>, <a href="/search/astro-ph?searchtype=author&query=Aggarwal%2C+N">N. Aggarwal</a>, <a href="/search/astro-ph?searchtype=author&query=Aguiar%2C+O+D">O. D. Aguiar</a>, <a href="/search/astro-ph?searchtype=author&query=Aiello%2C+L">L. Aiello</a>, <a href="/search/astro-ph?searchtype=author&query=Ain%2C+A">A. Ain</a>, <a href="/search/astro-ph?searchtype=author&query=Ajith%2C+P">P. Ajith</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+B">B. Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Allocca%2C+A">A. Allocca</a>, <a href="/search/astro-ph?searchtype=author&query=Altin%2C+P+A">P. A. Altin</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+S+B">S. B. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+W+G">W. G. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Arai%2C+K">K. Arai</a> , et al. (1522 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="1604.07864v3-abstract-short" style="display: inline;"> This Supplement provides supporting material for arXiv:1602.08492 . We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the dif… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.07864v3-abstract-full').style.display = 'inline'; document.getElementById('1604.07864v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1604.07864v3-abstract-full" style="display: none;"> This Supplement provides supporting material for arXiv:1602.08492 . We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.07864v3-abstract-full').style.display = 'none'; document.getElementById('1604.07864v3-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> 21 July, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">For the main Letter, see arXiv:1602.08492</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> LIGO-P1600137-v2 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal Supplement Series, 225:8 (15pp), 2016 July </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1604.03349">arXiv:1604.03349</a> <span> [<a href="https://arxiv.org/pdf/1604.03349">pdf</a>, <a href="https://arxiv.org/ps/1604.03349">ps</a>, <a href="https://arxiv.org/format/1604.03349">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="High Energy Physics - Experiment">hep-ex</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/10.1103/PhysRevD.93.082001">10.1103/PhysRevD.93.082001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measurement of the high-energy gamma-ray emission from the Moon with the Fermi Large Area Telescope </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+A">A. Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Atwood%2C+W+B">W. B. Atwood</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">C. Cecchi</a>, <a href="/search/astro-ph?searchtype=author&query=Chekhtman%2C+A">A. Chekhtman</a>, <a href="/search/astro-ph?searchtype=author&query=Chiang%2C+J">J. Chiang</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">G. Chiaro</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a> , et al. (90 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="1604.03349v2-abstract-short" style="display: inline;"> We have measured the gamma-ray emission spectrum of the Moon using the data collected by the Large Area Telescope onboard the Fermi satellite during its first 7 years of operation, in the energy range from 30 MeV up to a few GeV. We have also studied the time evolution of the flux, finding a correlation with the solar activity. We have developed a full Monte Carlo simulation describing the interac… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.03349v2-abstract-full').style.display = 'inline'; document.getElementById('1604.03349v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1604.03349v2-abstract-full" style="display: none;"> We have measured the gamma-ray emission spectrum of the Moon using the data collected by the Large Area Telescope onboard the Fermi satellite during its first 7 years of operation, in the energy range from 30 MeV up to a few GeV. We have also studied the time evolution of the flux, finding a correlation with the solar activity. We have developed a full Monte Carlo simulation describing the interactions of cosmic rays with the lunar surface. The results of the present analysis can be explained in the framework of this model, where the production of gamma rays is due to the interactions of cosmic-ray proton and helium nuclei with the surface of the Moon. Finally, we have used our simulation to derive the cosmic-ray proton and helium spectra near Earth from the Moon gamma-ray data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.03349v2-abstract-full').style.display = 'none'; document.getElementById('1604.03349v2-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> 13 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">Published by PRD, 16 pages, 11 figures, corresponding authors: F. Loparco and M. N. Mazziotta</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1603.06817">arXiv:1603.06817</a> <span> [<a href="https://arxiv.org/pdf/1603.06817">pdf</a>, <a href="https://arxiv.org/format/1603.06817">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 Detectors">physics.ins-det</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="High Energy Physics - Experiment">hep-ex</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.nima.2016.06.031">10.1016/j.nima.2016.06.031 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measurement of 1.7 to 74 MeV polarised gamma rays with the HARPO TPC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Geerebaert%2C+Y">Y. Geerebaert</a>, <a href="/search/astro-ph?searchtype=author&query=Gros%2C+P">Ph. Gros</a>, <a href="/search/astro-ph?searchtype=author&query=Amano%2C+S">S. Amano</a>, <a href="/search/astro-ph?searchtype=author&query=Atti%C3%A9%2C+D">D. Atti茅</a>, <a href="/search/astro-ph?searchtype=author&query=Bernard%2C+D">D. Bernard</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Calvet%2C+D">D. Calvet</a>, <a href="/search/astro-ph?searchtype=author&query=Colas%2C+P">P. Colas</a>, <a href="/search/astro-ph?searchtype=author&query=Dat%C3%A9%2C+S">S. Dat茅</a>, <a href="/search/astro-ph?searchtype=author&query=Delbart%2C+A">A. Delbart</a>, <a href="/search/astro-ph?searchtype=author&query=Frotin%2C+M">M. Frotin</a>, <a href="/search/astro-ph?searchtype=author&query=Giebels%2C+B">B. Giebels</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B6tz%2C+D">D. G枚tz</a>, <a href="/search/astro-ph?searchtype=author&query=Hashimoto%2C+S">S. Hashimoto</a>, <a href="/search/astro-ph?searchtype=author&query=Horan%2C+D">D. Horan</a>, <a href="/search/astro-ph?searchtype=author&query=Kotaka%2C+T">T. Kotaka</a>, <a href="/search/astro-ph?searchtype=author&query=Louzir%2C+M">M. Louzir</a>, <a href="/search/astro-ph?searchtype=author&query=Minamiyama%2C+Y">Y. Minamiyama</a>, <a href="/search/astro-ph?searchtype=author&query=Miyamoto%2C+S">S. Miyamoto</a>, <a href="/search/astro-ph?searchtype=author&query=Ohkuma%2C+H">H. Ohkuma</a>, <a href="/search/astro-ph?searchtype=author&query=Poilleux%2C+P">P. Poilleux</a>, <a href="/search/astro-ph?searchtype=author&query=Semeniouk%2C+I">I. Semeniouk</a>, <a href="/search/astro-ph?searchtype=author&query=Sizun%2C+P">P. Sizun</a>, <a href="/search/astro-ph?searchtype=author&query=Takemoto%2C+A">A. Takemoto</a>, <a href="/search/astro-ph?searchtype=author&query=Yamaguchi%2C+M">M. Yamaguchi</a> , et al. (1 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="1603.06817v1-abstract-short" style="display: inline;"> Current 纬-ray telescopes based on photon conversions to electron-positron pairs, such as Fermi, use tungsten converters. They suffer of limited angular resolution at low energies, and their sensitivity drops below 1 GeV. The low multiple scattering in a gaseous detector gives access to higher angular resolution in the MeV-GeV range, and to the linear polarisation of the photons through the azimuth… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.06817v1-abstract-full').style.display = 'inline'; document.getElementById('1603.06817v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1603.06817v1-abstract-full" style="display: none;"> Current 纬-ray telescopes based on photon conversions to electron-positron pairs, such as Fermi, use tungsten converters. They suffer of limited angular resolution at low energies, and their sensitivity drops below 1 GeV. The low multiple scattering in a gaseous detector gives access to higher angular resolution in the MeV-GeV range, and to the linear polarisation of the photons through the azimuthal angle of the electron-positron pair. HARPO is an R&D program to characterise the operation of a TPC (Time Projection Chamber) as a high angular-resolution and sensitivity telescope and polarimeter for 纬 rays from cosmic sources. It represents a first step towards a future space instrument. A 30 cm cubic TPC demonstrator was built, and filled with 2 bar argon-based gas. It was put in a polarised 纬-ray beam at the NewSUBARU accelerator in Japan in November 2014. Data were taken at different photon energies from 1.7 MeV to 74 MeV, and with different polarisation configurations. The electronics setup is described, with an emphasis on the trigger system. The event reconstruction algorithm is quickly described, and preliminary measurements of the polarisation of 11 MeVphotons are shown. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.06817v1-abstract-full').style.display = 'none'; document.getElementById('1603.06817v1-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 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">Proceedings VCI2016</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.08492">arXiv:1602.08492</a> <span> [<a href="https://arxiv.org/pdf/1602.08492">pdf</a>, <a href="https://arxiv.org/format/1602.08492">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="General Relativity and Quantum Cosmology">gr-qc</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/10.3847/2041-8205/826/1/L13">10.3847/2041-8205/826/1/L13 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Localization and broadband follow-up of the gravitational-wave transient GW150914 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abbott%2C+B+P">B. P. Abbott</a>, <a href="/search/astro-ph?searchtype=author&query=Abbott%2C+R">R. Abbott</a>, <a href="/search/astro-ph?searchtype=author&query=Abbott%2C+T+D">T. D. Abbott</a>, <a href="/search/astro-ph?searchtype=author&query=Abernathy%2C+M+R">M. R. Abernathy</a>, <a href="/search/astro-ph?searchtype=author&query=Acernese%2C+F">F. Acernese</a>, <a href="/search/astro-ph?searchtype=author&query=Ackley%2C+K">K. Ackley</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+C">C. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+T">T. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Addesso%2C+P">P. Addesso</a>, <a href="/search/astro-ph?searchtype=author&query=Adhikari%2C+R+X">R. X. Adhikari</a>, <a href="/search/astro-ph?searchtype=author&query=Adya%2C+V+B">V. B. Adya</a>, <a href="/search/astro-ph?searchtype=author&query=Affeldt%2C+C">C. Affeldt</a>, <a href="/search/astro-ph?searchtype=author&query=Agathos%2C+M">M. Agathos</a>, <a href="/search/astro-ph?searchtype=author&query=Agatsuma%2C+K">K. Agatsuma</a>, <a href="/search/astro-ph?searchtype=author&query=Aggarwal%2C+N">N. Aggarwal</a>, <a href="/search/astro-ph?searchtype=author&query=Aguiar%2C+O+D">O. D. Aguiar</a>, <a href="/search/astro-ph?searchtype=author&query=Aiello%2C+L">L. Aiello</a>, <a href="/search/astro-ph?searchtype=author&query=Ain%2C+A">A. Ain</a>, <a href="/search/astro-ph?searchtype=author&query=Ajith%2C+P">P. Ajith</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+B">B. Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Allocca%2C+A">A. Allocca</a>, <a href="/search/astro-ph?searchtype=author&query=Altin%2C+P+A">P. A. Altin</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+S+B">S. B. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+W+G">W. G. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Arai%2C+K">K. Arai</a> , et al. (1522 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="1602.08492v4-abstract-short" style="display: inline;"> A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared wit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08492v4-abstract-full').style.display = 'inline'; document.getElementById('1602.08492v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.08492v4-abstract-full" style="display: none;"> A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08492v4-abstract-full').style.display = 'none'; document.getElementById('1602.08492v4-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> 21 July, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 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">For Supplement, see https://arxiv.org/abs/1604.07864</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> LIGO-P1500227-v12 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal Letters, 826:L13 (8pp), 2016 July 20 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.07246">arXiv:1602.07246</a> <span> [<a href="https://arxiv.org/pdf/1602.07246">pdf</a>, <a href="https://arxiv.org/format/1602.07246">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/10.3847/0067-0049/223/2/26">10.3847/0067-0049/223/2/26 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Development of the Model of Galactic Interstellar Emission for Standard Point-Source Analysis of Fermi Large Area Telescope Data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Acero%2C+F">F. Acero</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+A">A. Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Brandt%2C+T+J">T. J. Brandt</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Casandjian%2C+J+M">J. M. Casandjian</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">C. Cecchi</a> , et al. (109 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="1602.07246v1-abstract-short" style="display: inline;"> Most of the celestial gamma rays detected by the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope originate from the interstellar medium when energetic cosmic rays interact with interstellar nucleons and photons. Conventional point and extended source studies rely on the modeling of this diffuse emission for accurate characterization. We describe here the development of the Ga… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.07246v1-abstract-full').style.display = 'inline'; document.getElementById('1602.07246v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.07246v1-abstract-full" style="display: none;"> Most of the celestial gamma rays detected by the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope originate from the interstellar medium when energetic cosmic rays interact with interstellar nucleons and photons. Conventional point and extended source studies rely on the modeling of this diffuse emission for accurate characterization. We describe here the development of the Galactic Interstellar Emission Model (GIEM) that is the standard adopted by the LAT Collaboration and is publicly available. The model is based on a linear combination of maps for interstellar gas column density in Galactocentric annuli and for the inverse Compton emission produced in the Galaxy. We also include in the GIEM large-scale structures like Loop I and the Fermi bubbles. The measured gas emissivity spectra confirm that the cosmic-ray proton density decreases with Galactocentric distance beyond 5 kpc from the Galactic Center. The measurements also suggest a softening of the proton spectrum with Galactocentric distance. We observe that the Fermi bubbles have boundaries with a shape similar to a catenary at latitudes below 20 degrees and we observe an enhanced emission toward their base extending in the North and South Galactic direction and located within 4 degrees of the Galactic Center. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.07246v1-abstract-full').style.display = 'none'; document.getElementById('1602.07246v1-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 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 ApJS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJS 223 26 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1512.04435">arXiv:1512.04435</a> <span> [<a href="https://arxiv.org/pdf/1512.04435">pdf</a>, <a href="https://arxiv.org/format/1512.04435">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey 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/10.1088/2041-8205/815/2/L23">10.1088/2041-8205/815/2/L23 <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-rays from the Universe's middle age: detection of the z=0.940 blazar PKS 1441+25 with MAGIC </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=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+A">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=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=Biassuzzi%2C+B">B. Biassuzzi</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=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=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>, <a href="/search/astro-ph?searchtype=author&query=Colombo%2C+E">E. Colombo</a> , et al. (229 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="1512.04435v3-abstract-short" style="display: inline;"> The flat-spectrum radio quasar PKS 1441+25 at a redshift of z = 0.940 is detected between 40 and 250 GeV with a significance of 25.5 蟽 using the MAGIC telescopes. Together with the gravitationally lensed blazar QSO B0218+357 (z = 0.944), PKS 1441+25 is the most distant very high energy (VHE) blazar detected to date. The observations were triggered by an outburst in 2015 April seen at GeV energies… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.04435v3-abstract-full').style.display = 'inline'; document.getElementById('1512.04435v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1512.04435v3-abstract-full" style="display: none;"> The flat-spectrum radio quasar PKS 1441+25 at a redshift of z = 0.940 is detected between 40 and 250 GeV with a significance of 25.5 蟽 using the MAGIC telescopes. Together with the gravitationally lensed blazar QSO B0218+357 (z = 0.944), PKS 1441+25 is the most distant very high energy (VHE) blazar detected to date. The observations were triggered by an outburst in 2015 April seen at GeV energies with the Large Area Telescope on board Fermi. Multi-wavelength observations suggest a subdivision of the high state into two distinct flux states. In the band covered by MAGIC, the variability time scale is estimated to be 6.4 +/- 1.9 days. Modeling the broadband spectral energy distribution with an external Compton model, the location of the emitting region is understood as originating in the jet outside the broad line region (BLR) during the period of high activity, while being partially within the BLR during the period of low (typical) activity. The observed VHE spectrum during the highest activity is used to probe the extragalactic background light at an unprecedented distance scale for ground-based gamma-ray astronomy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.04435v3-abstract-full').style.display = 'none'; document.getElementById('1512.04435v3-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 January, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 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">Corresponding Authors: J. Becerra (josefa.becerra@nasa.gov), M. Nievas Rosillo (mnievas@ucm.es), M. Manganaro (manganaro@iac.es), F. Tavecchio (fabrizio.tavecchio@brera.inaf.it) Published in The Astrophysical Journal Letters (ApJL), 2015ApJ...815L..23A, DOI: 10.1088/2041-8205/815/2/L23</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJL, 2015, 815, L23 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1511.06778">arXiv:1511.06778</a> <span> [<a href="https://arxiv.org/pdf/1511.06778">pdf</a>, <a href="https://arxiv.org/format/1511.06778">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="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/10.3847/0067-0049/224/1/8">10.3847/0067-0049/224/1/8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The 1st Fermi Lat Supernova Remnant Catalog </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Acero%2C+F">Fabio Acero</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">Markus Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">Marco Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">Luca Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">Jean Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">Guido Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">Denis Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">Ronaldo Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R">Roger Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">Raffaella Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">Eugenio Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">Philippe Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">Rolf Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">Rob A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">Micaela Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">Patrizia A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Casandjian%2C+J+M">Jean Marc Casandjian</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">Elisabetta Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">Claudia Cecchi</a> , et al. (134 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="1511.06778v1-abstract-short" style="display: inline;"> To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope. Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.06778v1-abstract-full').style.display = 'inline'; document.getElementById('1511.06778v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1511.06778v1-abstract-full" style="display: none;"> To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope. Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245 flux upper limits. A mock catalog in which the positions of known remnants are scrambled in Galactic longitude, allows us to determine an upper limit of 22% on the number of GeV candidates falsely identified as SNRs. We have also developed a method to estimate spectral and spatial systematic errors arising from the diffuse interstellar emission model, a key component of all Galactic Fermi LAT analyses. By studying remnants uniformly in aggregate, we measure the GeV properties common to these objects and provide a crucial context for the detailed modeling of individual SNRs. Combining our GeV results with multiwavelength (MW) data, including radio, X-ray, and TeV, demonstrates the need for improvements to previously sufficient, simple models describing the GeV and radio emission from these objects. We model the GeV and MW emission from SNRs in aggregate to constrain their maximal contribution to observed Galactic cosmic rays. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.06778v1-abstract-full').style.display = 'none'; document.getElementById('1511.06778v1-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 November, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">Resubmitted to ApJS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJS 224 8 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1510.00004">arXiv:1510.00004</a> <span> [<a href="https://arxiv.org/pdf/1510.00004">pdf</a>, <a href="https://arxiv.org/format/1510.00004">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="High Energy Physics - Phenomenology">hep-ph</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/812/2/159">10.1088/0004-637X/812/2/159 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for extended gamma-ray emission from the Virgo galaxy cluster with Fermi-LAT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+A">A. Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Atwood%2C+W+B">W. B. Atwood</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bechtol%2C+K">K. Bechtol</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Brandt%2C+T+J">T. J. Brandt</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R. Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Casandjian%2C+J+M">J. M. Casandjian</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a> , et al. (96 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="1510.00004v1-abstract-short" style="display: inline;"> Galaxy clusters are one of the prime sites to search for dark matter (DM) annihilation signals. Depending on the substructure of the DM halo of a galaxy cluster and the cross sections for DM annihilation channels, these signals might be detectable by the latest generation of $纬$-ray telescopes. Here we use three years of Fermi Large Area Telescope (LAT) data, which are the most suitable for search… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.00004v1-abstract-full').style.display = 'inline'; document.getElementById('1510.00004v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1510.00004v1-abstract-full" style="display: none;"> Galaxy clusters are one of the prime sites to search for dark matter (DM) annihilation signals. Depending on the substructure of the DM halo of a galaxy cluster and the cross sections for DM annihilation channels, these signals might be detectable by the latest generation of $纬$-ray telescopes. Here we use three years of Fermi Large Area Telescope (LAT) data, which are the most suitable for searching for very extended emission in the vicinity of nearby Virgo galaxy cluster. Our analysis reveals statistically significant extended emission which can be well characterized by a uniformly emitting disk profile with a radius of 3掳that moreover is offset from the cluster center. We demonstrate that the significance of this extended emission strongly depends on the adopted interstellar emission model (IEM) and is most likely an artifact of our incomplete description of the IEM in this region. We also search for and find new point source candidates in the region. We then derive conservative upper limits on the velocity-averaged DM pair annihilation cross section from Virgo. We take into account the potential $纬$-ray flux enhancement due to DM sub-halos and its complex morphology as a merging cluster. For DM annihilating into $b\overline{b}$, assuming a conservative sub-halo model setup, we find limits that are between 1 and 1.5 orders of magnitude above the expectation from the thermal cross section for $m_{\mathrm{DM}}\lesssim100\,\mathrm{GeV}$. In a more optimistic scenario, we exclude $\langle 蟽v \rangle\sim3\times10^{-26}\,\mathrm{cm^{3}\,s^{-1}}$ for $m_{\mathrm{DM}}\lesssim40\,\mathrm{GeV}$ for the same channel. Finally, we derive upper limits on the $纬$-ray-flux produced by hadronic cosmic-ray interactions in the inter cluster medium. We find that the volume-averaged cosmic-ray-to-thermal pressure ratio is less than $\sim6\%$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.00004v1-abstract-full').style.display = 'none'; document.getElementById('1510.00004v1-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 September, 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">15 pages, 11 figures, 4 tables, accepted for publication in ApJ; corresponding authors: T. Jogler, S. Zimmer & A. Pinzke</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 812 159 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.02063">arXiv:1509.02063</a> <span> [<a href="https://arxiv.org/pdf/1509.02063">pdf</a>, <a href="https://arxiv.org/ps/1509.02063">ps</a>, <a href="https://arxiv.org/format/1509.02063">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/10.1088/2041-8205/813/2/L41">10.1088/2041-8205/813/2/L41 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multiwavelength Evidence for Quasi-periodic Modulation in the Gamma-ray Blazar PG 1553+113 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+Fermi+LAT+collaboration"> The Fermi LAT collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+A">A. Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Atwood%2C+W+B">W. B. Atwood</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J+B">J. Becerra Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caputo%2C+R">R. Caputo</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a> , et al. (117 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="1509.02063v3-abstract-short" style="display: inline;"> We report for the first time a gamma-ray and multi-wavelength nearly-periodic oscillation in an active galactic nucleus. Using the Fermi Large Area Telescope (LAT) we have discovered an apparent quasi-periodicity in the gamma-ray flux (E >100 MeV) from the GeV/TeV BL Lac object PG 1553+113. The marginal significance of the 2.18 +/-0.08 year-period gamma-ray cycle is strengthened by correlated osci… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.02063v3-abstract-full').style.display = 'inline'; document.getElementById('1509.02063v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.02063v3-abstract-full" style="display: none;"> We report for the first time a gamma-ray and multi-wavelength nearly-periodic oscillation in an active galactic nucleus. Using the Fermi Large Area Telescope (LAT) we have discovered an apparent quasi-periodicity in the gamma-ray flux (E >100 MeV) from the GeV/TeV BL Lac object PG 1553+113. The marginal significance of the 2.18 +/-0.08 year-period gamma-ray cycle is strengthened by correlated oscillations observed in radio and optical fluxes, through data collected in the OVRO, Tuorla, KAIT, and CSS monitoring programs and Swift UVOT. The optical cycle appearing in ~10 years of data has a similar period, while the 15 GHz oscillation is less regular than seen in the other bands. Further long-term multi-wavelength monitoring of this blazar may discriminate among the possible explanations for this quasi-periodicity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.02063v3-abstract-full').style.display = 'none'; document.getElementById('1509.02063v3-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 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 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">8 pages, 5 figures. Accepted to The Astrophysical Journal Letters. Corresponding authors: S. Ciprini (ASDC/INFN), S. Cutini (ASDC/INFN), S. Larsson (Stockholm Univ/KTH), A. Stamerra (INAF/SNS), D. J. Thompson (NASA GSFC)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1508.00779">arXiv:1508.00779</a> <span> [<a href="https://arxiv.org/pdf/1508.00779">pdf</a>, <a href="https://arxiv.org/format/1508.00779">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/10.1088/2041-8205/809/1/L2">10.1088/2041-8205/809/1/L2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> PSR J1906+0722: An Elusive Gamma-ray Pulsar </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Clark%2C+C+J">C. J. Clark</a>, <a href="/search/astro-ph?searchtype=author&query=Pletsch%2C+H+J">H. J. Pletsch</a>, <a href="/search/astro-ph?searchtype=author&query=Wu%2C+J">J. Wu</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">L. Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+B">B. Allen</a>, <a href="/search/astro-ph?searchtype=author&query=de+Angelis%2C+A">A. de Angelis</a>, <a href="/search/astro-ph?searchtype=author&query=Aulbert%2C+C">C. Aulbert</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bock%2C+O">O. Bock</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Brandt%2C+T+J">T. J. Brandt</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a> , et al. (95 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="1508.00779v1-abstract-short" style="display: inline;"> We report the discovery of PSR J1906+0722, a gamma-ray pulsar detected as part of a blind survey of unidentified Fermi Large Area Telescope (LAT) sources being carried out on the volunteer distributed computing system, Einstein@Home. This newly discovered pulsar previously appeared as the most significant remaining unidentified gamma-ray source without a known association in the second Fermi-LAT s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1508.00779v1-abstract-full').style.display = 'inline'; document.getElementById('1508.00779v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1508.00779v1-abstract-full" style="display: none;"> We report the discovery of PSR J1906+0722, a gamma-ray pulsar detected as part of a blind survey of unidentified Fermi Large Area Telescope (LAT) sources being carried out on the volunteer distributed computing system, Einstein@Home. This newly discovered pulsar previously appeared as the most significant remaining unidentified gamma-ray source without a known association in the second Fermi-LAT source catalog (2FGL) and was among the top ten most significant unassociated sources in the recent third catalog (3FGL). PSR J1906+0722 is a young, energetic, isolated pulsar, with a spin frequency of $8.9$ Hz, a characteristic age of $49$ kyr, and spin-down power $1.0 \times 10^{36}$ erg s$^{-1}$. In 2009 August it suffered one of the largest glitches detected from a gamma-ray pulsar ($螖f / f \approx 4.5\times10^{-6}$). Remaining undetected in dedicated radio follow-up observations, the pulsar is likely radio-quiet. An off-pulse analysis of the gamma-ray flux from the location of PSR J1906+0722 revealed the presence of an additional nearby source, which may be emission from the interaction between a neighboring supernova remnant and a molecular cloud. We discuss possible effects which may have hindered the detection of PSR J1906+0722 in previous searches and describe the methods by which these effects were mitigated in this survey. We also demonstrate the use of advanced timing methods for estimating the positional, spin and glitch parameters of difficult-to-time pulsars such as this. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1508.00779v1-abstract-full').style.display = 'none'; document.getElementById('1508.00779v1-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, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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, 4 figures, accepted for publication in Astrophysical Journal Letters</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 809 L2 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1506.01647">arXiv:1506.01647</a> <span> [<a href="https://arxiv.org/pdf/1506.01647">pdf</a>, <a href="https://arxiv.org/format/1506.01647">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/807/2/169">10.1088/0004-637X/807/2/169 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for Early Gamma-ray Production in Supernovae Located in a Dense Circumstellar Medium with the Fermi LAT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Arcavi%2C+I">I. Arcavi</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Brandt%2C+T+J">T. J. Brandt</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">C. Cecchi</a>, <a href="/search/astro-ph?searchtype=author&query=Charles%2C+E">E. Charles</a>, <a href="/search/astro-ph?searchtype=author&query=Chekhtman%2C+A">A. Chekhtman</a>, <a href="/search/astro-ph?searchtype=author&query=Chiang%2C+J">J. Chiang</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="1506.01647v2-abstract-short" style="display: inline;"> Supernovae (SNe) exploding in a dense circumstellar medium (CSM) are hypothesized to accelerate cosmic rays in collisionless shocks and emit GeV gamma rays and TeV neutrinos on a time scale of several months. We perform the first systematic search for gamma-ray emission in Fermi LAT data in the energy range from 100 MeV to 300 GeV from the ensemble of 147 SNe Type IIn exploding in dense CSM. We se… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.01647v2-abstract-full').style.display = 'inline'; document.getElementById('1506.01647v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1506.01647v2-abstract-full" style="display: none;"> Supernovae (SNe) exploding in a dense circumstellar medium (CSM) are hypothesized to accelerate cosmic rays in collisionless shocks and emit GeV gamma rays and TeV neutrinos on a time scale of several months. We perform the first systematic search for gamma-ray emission in Fermi LAT data in the energy range from 100 MeV to 300 GeV from the ensemble of 147 SNe Type IIn exploding in dense CSM. We search for a gamma-ray excess at each SNe location in a one year time window. In order to enhance a possible weak signal, we simultaneously study the closest and optically brightest sources of our sample in a joint-likelihood analysis in three different time windows (1 year, 6 months and 3 months). For the most promising source of the sample, SN 2010jl (PTF10aaxf), we repeat the analysis with an extended time window lasting 4.5 years. We do not find a significant excess in gamma rays for any individual source nor for the combined sources and provide model-independent flux upper limits for both cases. In addition, we derive limits on the gamma-ray luminosity and the ratio of gamma-ray-to-optical luminosity ratio as a function of the index of the proton injection spectrum assuming a generic gamma-ray production model. Furthermore, we present detailed flux predictions based on multi-wavelength observations and the corresponding flux upper limit at 95% confidence level (CL) for the source SN 2010jl (PTF10aaxf). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.01647v2-abstract-full').style.display = 'none'; document.getElementById('1506.01647v2-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 June, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 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">Accepted for publication in ApJ. Corresponding author: A. Franckowiak (afrancko@slac.stanford.edu), updated author list and acknowledgements</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ, 807, 169 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1503.03772">arXiv:1503.03772</a> <span> [<a href="https://arxiv.org/pdf/1503.03772">pdf</a>, <a href="https://arxiv.org/format/1503.03772">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="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/10.1088/1742-6596/650/1/012016">10.1088/1742-6596/650/1/012016 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> HARPO: beam characterization of a TPC for gamma-ray polarimetry and high angular-resolution astronomy in the MeV-GeV range </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Wang%2C+S">Shaobo Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Bernard%2C+D">Denis Bernard</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">Philippe Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Frotin%2C+M">Mickael Frotin</a>, <a href="/search/astro-ph?searchtype=author&query=Geerebaert%2C+Y">Yannick Geerebaert</a>, <a href="/search/astro-ph?searchtype=author&query=Giebels%2C+B">Berrie Giebels</a>, <a href="/search/astro-ph?searchtype=author&query=Gros%2C+P">Philippe Gros</a>, <a href="/search/astro-ph?searchtype=author&query=Horan%2C+D">Deirdre Horan</a>, <a href="/search/astro-ph?searchtype=author&query=Louzir%2C+M">Marc Louzir</a>, <a href="/search/astro-ph?searchtype=author&query=Poilleux%2C+P">Patrick Poilleux</a>, <a href="/search/astro-ph?searchtype=author&query=Semeniouk%2C+I">Igor Semeniouk</a>, <a href="/search/astro-ph?searchtype=author&query=Atti%C3%A9%2C+D">David Atti茅</a>, <a href="/search/astro-ph?searchtype=author&query=Calvet%2C+D">Denis Calvet</a>, <a href="/search/astro-ph?searchtype=author&query=Colas%2C+P">Paul Colas</a>, <a href="/search/astro-ph?searchtype=author&query=Delbart%2C+A">Alain Delbart</a>, <a href="/search/astro-ph?searchtype=author&query=Sizun%2C+P">Patrick Sizun</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B6tz%2C+D">Diego G枚tz</a>, <a href="/search/astro-ph?searchtype=author&query=Amano%2C+S">Sho Amano</a>, <a href="/search/astro-ph?searchtype=author&query=Kotaka%2C+T">Takuya Kotaka</a>, <a href="/search/astro-ph?searchtype=author&query=Hashimoto%2C+S">Satoshi Hashimoto</a>, <a href="/search/astro-ph?searchtype=author&query=Minamiyama%2C+Y">Yasuhito Minamiyama</a>, <a href="/search/astro-ph?searchtype=author&query=Takemoto%2C+A">Akinori Takemoto</a>, <a href="/search/astro-ph?searchtype=author&query=Yamaguchi%2C+M">Masashi Yamaguchi</a>, <a href="/search/astro-ph?searchtype=author&query=Miyamoto%2C+S">Shuji Miyamoto</a>, <a href="/search/astro-ph?searchtype=author&query=Dat%C3%A9%2C+S">Schin Dat茅</a> , et al. (1 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="1503.03772v1-abstract-short" style="display: inline;"> A time projection chamber (TPC) can be used to measure the polarization of gamma rays with excellent angular precision and sensitivity in the MeV-GeV energy range through the conversion of photons to e+e- pairs. The Hermetic ARgon POlarimeter (HARPO) prototype was built to demonstrate this concept. It was recently tested in the polarized photon beam at the NewSUBARU facility in Japan. We present t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1503.03772v1-abstract-full').style.display = 'inline'; document.getElementById('1503.03772v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1503.03772v1-abstract-full" style="display: none;"> A time projection chamber (TPC) can be used to measure the polarization of gamma rays with excellent angular precision and sensitivity in the MeV-GeV energy range through the conversion of photons to e+e- pairs. The Hermetic ARgon POlarimeter (HARPO) prototype was built to demonstrate this concept. It was recently tested in the polarized photon beam at the NewSUBARU facility in Japan. We present this data-taking run, which demonstrated the excellent performance of the HARPO TPC. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1503.03772v1-abstract-full').style.display = 'none'; document.getElementById('1503.03772v1-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 March, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">12 pages, 11 figures, presented at the 7th Symposium on large TPCs for low-energy rare event detection, Paris, France, 15-17 December 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/1501.06054">arXiv:1501.06054</a> <span> [<a href="https://arxiv.org/pdf/1501.06054">pdf</a>, <a href="https://arxiv.org/ps/1501.06054">ps</a>, <a href="https://arxiv.org/format/1501.06054">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/810/1/14">10.1088/0004-637X/810/1/14 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Atwood%2C+W">W. Atwood</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J">J. Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R">R. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E">E. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Brandt%2C+T">T. Brandt</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Britto%2C+R">R. Britto</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G">G. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R">R. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P">P. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Casandjian%2C+J">J. Casandjian</a> , et al. (118 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="1501.06054v2-abstract-short" style="display: inline;"> The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It is based on the third Fermi-LAT catalog (3FGL) of sources detected between 100 MeV and 300 GeV with a Test Statistic (TS) greater than 25, between 2008 August 4 and 2012 July 31. The 3LAC includes 1591 AGNs located at high Galactic latitudes (|b|>10掳), a 71% increase over the second catalog based o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.06054v2-abstract-full').style.display = 'inline'; document.getElementById('1501.06054v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1501.06054v2-abstract-full" style="display: none;"> The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It is based on the third Fermi-LAT catalog (3FGL) of sources detected between 100 MeV and 300 GeV with a Test Statistic (TS) greater than 25, between 2008 August 4 and 2012 July 31. The 3LAC includes 1591 AGNs located at high Galactic latitudes (|b|>10掳), a 71% increase over the second catalog based on 2 years of data. There are 28 duplicate associations, thus 1563 of the 2192 high-latitude gamma-ray sources of the 3FGL catalog are AGNs. Most of them (98%) are blazars. About half of the newly detected blazars are of unknown type, i.e., they lack spectroscopic information of sufficient quality to determine the strength of their emission lines. Based on their gamma-ray spectral properties, these sources are evenly split between flat-spectrum radio quasars (FSRQs) and BL~Lacs. The most abundant detected BL~Lacs are of the high-synchrotron-peaked (HSP) type. About 50% of the BL~Lacs have no measured redshifts. A few new rare outliers (HSP-FSRQs and high-luminosity HSP BL~Lacs) are reported. The general properties of the 3LAC sample confirm previous findings from earlier catalogs. The fraction of 3LAC blazars in the total population of blazars listed in BZCAT remains non-negligible even at the faint ends of the BZCAT-blazar radio, optical and X-ray flux distributions, which is a clue that even the faintest known blazars could eventually shine in gamma rays at LAT-detection levels. The energy-flux distributions of the different blazar populations are in good agreement with extrapolation from earlier catalogs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.06054v2-abstract-full').style.display = 'none'; document.getElementById('1501.06054v2-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 August, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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 by ApJ. Updated to published version</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1501.05464">arXiv:1501.05464</a> <span> [<a href="https://arxiv.org/pdf/1501.05464">pdf</a>, <a href="https://arxiv.org/format/1501.05464">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey 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/10.1088/1475-7516/2015/09/008">10.1088/1475-7516/2015/09/008 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Limits on Dark Matter Annihilation Signals from the Fermi LAT 4-year Measurement of the Isotropic Gamma-Ray Background </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+Fermi+LAT+Collaboration"> The Fermi LAT Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+A">A. Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bechtol%2C+K">K. Bechtol</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">R. Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">C. Cecchi</a>, <a href="/search/astro-ph?searchtype=author&query=Charles%2C+E">E. Charles</a>, <a href="/search/astro-ph?searchtype=author&query=Chekhtman%2C+A">A. Chekhtman</a>, <a href="/search/astro-ph?searchtype=author&query=Chiang%2C+J">J. Chiang</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">G. Chiaro</a> , et al. (88 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="1501.05464v2-abstract-short" style="display: inline;"> We search for evidence of dark matter (DM) annihilation in the isotropic gamma-ray background (IGRB) measured with 50 months of Fermi Large Area Telescope (LAT) observations. An improved theoretical description of the cosmological DM annihilation signal, based on two complementary techniques and assuming generic weakly interacting massive particle (WIMP) properties, renders more precise prediction… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.05464v2-abstract-full').style.display = 'inline'; document.getElementById('1501.05464v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1501.05464v2-abstract-full" style="display: none;"> We search for evidence of dark matter (DM) annihilation in the isotropic gamma-ray background (IGRB) measured with 50 months of Fermi Large Area Telescope (LAT) observations. An improved theoretical description of the cosmological DM annihilation signal, based on two complementary techniques and assuming generic weakly interacting massive particle (WIMP) properties, renders more precise predictions compared to previous work. More specifically, we estimate the cosmologically-induced gamma-ray intensity to have an uncertainty of a factor ~20 in canonical setups. We consistently include both the Galactic and extragalactic signals under the same theoretical framework, and study the impact of the former on the IGRB spectrum derivation. We find no evidence for a DM signal and we set limits on the DM-induced isotropic gamma-ray signal. Our limits are competitive for DM particle masses up to tens of TeV and, indeed, are the strongest limits derived from Fermi LAT data at TeV energies. This is possible thanks to the new Fermi LAT IGRB measurement, which now extends up to an energy of 820 GeV. We quantify uncertainties in detail and show the potential this type of search offers for testing the WIMP paradigm with a complementary and truly cosmological probe of DM particle signals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.05464v2-abstract-full').style.display = 'none'; document.getElementById('1501.05464v2-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 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">Matches the JCAP published version. Corresponding authors: A. Franckowiak (afrancko@slac.stanford.edu), M. Gustafsson (michael.gustafsson@theorie.physik.uni-goettingen.de), M.A. Sanchez-Conde (sanchezconde@fysik.su.se), G. Zaharijas (gabrijela.zaharijas@ung.si)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1410.3696">arXiv:1410.3696</a> <span> [<a href="https://arxiv.org/pdf/1410.3696">pdf</a>, <a href="https://arxiv.org/format/1410.3696">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/799/1/86">10.1088/0004-637X/799/1/86 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+Fermi+LAT+collaboration"> The Fermi LAT collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+A">A. Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Atwood%2C+W+B">W. B. Atwood</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">L. Baldini</a>, <a href="/search/astro-ph?searchtype=author&query=Ballet%2C+J">J. Ballet</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bechtol%2C+K">K. Bechtol</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Blandford%2C+R+D">R. D. Blandford</a>, <a href="/search/astro-ph?searchtype=author&query=Bloom%2C+E+D">E. D. Bloom</a>, <a href="/search/astro-ph?searchtype=author&query=Bottacini%2C+E">E. Bottacini</a>, <a href="/search/astro-ph?searchtype=author&query=Brandt%2C+T+J">T. J. Brandt</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caragiulo%2C+M">M. Caragiulo</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a> , et al. (120 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="1410.3696v1-abstract-short" style="display: inline;"> The 纬-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the isotropic diffuse 纬-ray background (IGRB). The IGRB comprises all extragalactic emissions too faint or too diffuse to be resolved in a given survey, as well as any res… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.3696v1-abstract-full').style.display = 'inline'; document.getElementById('1410.3696v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1410.3696v1-abstract-full" style="display: none;"> The 纬-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the isotropic diffuse 纬-ray background (IGRB). The IGRB comprises all extragalactic emissions too faint or too diffuse to be resolved in a given survey, as well as any residual Galactic foregrounds that are approximately isotropic. The first IGRB measurement with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) used 10 months of sky-survey data and considered an energy range between 200 MeV and 100 GeV. Improvements in event selection and characterization of cosmic-ray backgrounds, better understanding of the diffuse Galactic emission, and a longer data accumulation of 50 months, allow for a refinement and extension of the IGRB measurement with the LAT, now covering the energy range from 100 MeV to 820 GeV. The IGRB spectrum shows a significant high-energy cutoff feature, and can be well described over nearly four decades in energy by a power law with exponential cutoff having a spectral index of $2.32\pm0.02$ and a break energy of $(279\pm52)$ GeV using our baseline diffuse Galactic emission model. The total intensity attributed to the IGRB is $(7.2\pm0.6) \times 10^{-6}$ cm$^{-2}$ s$^{-1}$ sr$^{-1}$ above 100 MeV, with an additional $+15$%/$-30$% systematic uncertainty due to the Galactic diffuse foregrounds. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.3696v1-abstract-full').style.display = 'none'; document.getElementById('1410.3696v1-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 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 by The Astrophysical Journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> M. Ackermann et al. 2015 ApJ 799 86 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1406.4830">arXiv:1406.4830</a> <span> [<a href="https://arxiv.org/pdf/1406.4830">pdf</a>, <a href="https://arxiv.org/format/1406.4830">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="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/10.1117/12.2055307">10.1117/12.2055307 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> HARPO: a TPC as a gamma-ray telescope and polarimeter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bernard%2C+D">Denis Bernard</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">Philippe Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Frotin%2C+M">Mickael Frotin</a>, <a href="/search/astro-ph?searchtype=author&query=Geerebaert%2C+Y">Yannick Geerebaert</a>, <a href="/search/astro-ph?searchtype=author&query=Giebels%2C+B">Berrie Giebels</a>, <a href="/search/astro-ph?searchtype=author&query=Gros%2C+P">Philippe Gros</a>, <a href="/search/astro-ph?searchtype=author&query=Horan%2C+D">Deirdre Horan</a>, <a href="/search/astro-ph?searchtype=author&query=Louzir%2C+M">Marc Louzir</a>, <a href="/search/astro-ph?searchtype=author&query=Poilleux%2C+P">Patrick Poilleux</a>, <a href="/search/astro-ph?searchtype=author&query=Semeniouk%2C+I">Igor Semeniouk</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+S">Shaobo Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Anvar%2C+S">Shebli Anvar</a>, <a href="/search/astro-ph?searchtype=author&query=Atti%C3%A9%2C+D">David Atti茅</a>, <a href="/search/astro-ph?searchtype=author&query=Colas%2C+P">Paul Colas</a>, <a href="/search/astro-ph?searchtype=author&query=Delbart%2C+A">Alain Delbart</a>, <a href="/search/astro-ph?searchtype=author&query=Sizun%2C+P">Patrick Sizun</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B6tz%2C+D">Diego G枚tz</a> </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="1406.4830v3-abstract-short" style="display: inline;"> A gas Time Projection Chamber can be used for gamma-ray astronomy with excellent angular-precision and sensitivity to faint sources, and for polarimetry, through the measurement of photon conversion to $e^+e^-$ pairs. We present the expected performance in simulations and the recent development of a demonstrator for tests in a polarized photon beam. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1406.4830v3-abstract-full" style="display: none;"> A gas Time Projection Chamber can be used for gamma-ray astronomy with excellent angular-precision and sensitivity to faint sources, and for polarimetry, through the measurement of photon conversion to $e^+e^-$ pairs. We present the expected performance in simulations and the recent development of a demonstrator for tests in a polarized photon beam. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.4830v3-abstract-full').style.display = 'none'; document.getElementById('1406.4830v3-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 July, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 June, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">SPIE Astronomical Telescopes + Instrumentation, Ultraviolet to gamma ray, Montr茅al, Canada 2014. v2: note added in proof. Copyright 2014 SPIE. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Proc. SPIE 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 91441M (July 24, 2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1403.7534">arXiv:1403.7534</a> <span> [<a href="https://arxiv.org/pdf/1403.7534">pdf</a>, <a href="https://arxiv.org/ps/1403.7534">ps</a>, <a href="https://arxiv.org/format/1403.7534">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</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/786/2/157">10.1088/0004-637X/786/2/157 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multifrequency Studies of the Peculiar Quasar 4C +21.35 During the 2010 Flaring Activity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ackermann%2C+M">M. Ackermann</a>, <a href="/search/astro-ph?searchtype=author&query=Ajello%2C+M">M. Ajello</a>, <a href="/search/astro-ph?searchtype=author&query=Allafort%2C+A">A. Allafort</a>, <a href="/search/astro-ph?searchtype=author&query=Antolini%2C+E">E. Antolini</a>, <a href="/search/astro-ph?searchtype=author&query=Barbiellini%2C+G">G. Barbiellini</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bellazzini%2C+R">R. Bellazzini</a>, <a href="/search/astro-ph?searchtype=author&query=Bissaldi%2C+E">E. Bissaldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bonamente%2C+E">E. Bonamente</a>, <a href="/search/astro-ph?searchtype=author&query=Bregeon%2C+J">J. Bregeon</a>, <a href="/search/astro-ph?searchtype=author&query=Brigida%2C+M">M. Brigida</a>, <a href="/search/astro-ph?searchtype=author&query=Bruel%2C+P">P. Bruel</a>, <a href="/search/astro-ph?searchtype=author&query=Buehler%2C+R">R. Buehler</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Caliandro%2C+G+A">G. A. Caliandro</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+R+A">R. A. Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Caraveo%2C+P+A">P. A. Caraveo</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">E. Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cecchi%2C+C">C. Cecchi</a>, <a href="/search/astro-ph?searchtype=author&query=Chaves%2C+R+C+G">R. C. G. Chaves</a>, <a href="/search/astro-ph?searchtype=author&query=Chekhtman%2C+A">A. Chekhtman</a>, <a href="/search/astro-ph?searchtype=author&query=Chiang%2C+J">J. Chiang</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaro%2C+G">G. Chiaro</a>, <a href="/search/astro-ph?searchtype=author&query=Ciprini%2C+S">S. Ciprini</a>, <a href="/search/astro-ph?searchtype=author&query=Claus%2C+R">R. Claus</a> , et al. (266 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="1403.7534v3-abstract-short" style="display: inline;"> The discovery of rapidly variable Very High Energy (VHE; E > 100 GeV) gamma-ray emission from 4C +21.35 (PKS 1222+216) by MAGIC on 2010 June 17, triggered by the high activity detected by the Fermi Large Area Telescope (LAT) in high energy (HE; E > 100 MeV) gamma-rays, poses intriguing questions on the location of the gamma-ray emitting region in this flat spectrum radio quasar. We present multifr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.7534v3-abstract-full').style.display = 'inline'; document.getElementById('1403.7534v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1403.7534v3-abstract-full" style="display: none;"> The discovery of rapidly variable Very High Energy (VHE; E > 100 GeV) gamma-ray emission from 4C +21.35 (PKS 1222+216) by MAGIC on 2010 June 17, triggered by the high activity detected by the Fermi Large Area Telescope (LAT) in high energy (HE; E > 100 MeV) gamma-rays, poses intriguing questions on the location of the gamma-ray emitting region in this flat spectrum radio quasar. We present multifrequency data of 4C +21.35 collected from centimeter to VHE during 2010 to investigate the properties of this source and discuss a possible emission model. The first hint of detection at VHE was observed by MAGIC on 2010 May 3, soon after a gamma-ray flare detected by Fermi-LAT that peaked on April 29. The same emission mechanism may therefore be responsible for both the HE and VHE emission during the 2010 flaring episodes. Two optical peaks were detected on 2010 April 20 and June 30, close in time but not simultaneous with the two gamma-ray peaks, while no clear connection was observed between the X-ray an gamma-ray emission. An increasing flux density was observed in radio and mm bands from the beginning of 2009, in accordance with the increasing gamma-ray activity observed by Fermi-LAT, and peaking on 2011 January 27 in the mm regime (230 GHz). We model the spectral energy distributions (SEDs) of 4C +21.35 for the two periods of the VHE detection and a quiescent state, using a one-zone model with the emission coming from a very compact region outside the broad line region. The three SEDs can be fit with a combination of synchrotron self-Compton and external Compton emission of seed photons from a dust torus, changing only the electron distribution parameters between the epochs. The fit of the optical/UV part of the spectrum for 2010 April 29 seems to favor an inner disk radius of <6 gravitational radii, as one would expect from a prograde-rotating Kerr black hole. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.7534v3-abstract-full').style.display = 'none'; document.getElementById('1403.7534v3-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 June, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 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">46 pages, 10 figures, 4 tables. The Astrophysical Journal, Volume 786, Issue 2, article id. 157, 17 pp. Contact Authors: Filippo D'Ammando, Justin Finke, Davide Donato, Josefa Becerra Gonzalez, Tomislav Terzic. Figure 1 updated</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=Bruel%2C+P&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Bruel%2C+P&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Bruel%2C+P&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </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 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