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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=Bonnoli%2C+G&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Bonnoli%2C+G&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Bonnoli%2C+G&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Bonnoli%2C+G&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=Bonnoli%2C+G&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> <li> <a href="/search/?searchtype=author&query=Bonnoli%2C+G&start=200" class="pagination-link " aria-label="Page 5" aria-current="page">5 </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/2411.16868">arXiv:2411.16868</a> <span> [<a href="https://arxiv.org/pdf/2411.16868">pdf</a>, <a href="https://arxiv.org/format/2411.16868">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"> IXPE Observation of the Low-Synchrotron Peaked Blazar S4 0954+65 During An Optical-X-ray Flare </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kouch%2C+P+M">Pouya M. Kouch</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Fenu%2C+F">Francesco Fenu</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+H">Haocheng Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Boula%2C+S">Stella Boula</a>, <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Paraschos%2C+G+F">Georgios F. Paraschos</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Lindfors%2C+E">Elina Lindfors</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">Henric Krawczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Negro%2C+M">Michela Negro</a>, <a href="/search/astro-ph?searchtype=author&query=Hu%2C+K">Kun Hu</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+E">Dawoon E. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">Elisabetta Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">Manel Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Blinov%2C+D">Dmitry Blinov</a>, <a href="/search/astro-ph?searchtype=author&query=Gourni%2C+A">Anastasia Gourni</a>, <a href="/search/astro-ph?searchtype=author&query=Kiehlmann%2C+S">Sebastian Kiehlmann</a>, <a href="/search/astro-ph?searchtype=author&query=Kourtidis%2C+A">Angelos Kourtidis</a>, <a href="/search/astro-ph?searchtype=author&query=Mandarakas%2C+N">Nikos Mandarakas</a>, <a href="/search/astro-ph?searchtype=author&query=Triantafyllou%2C+N">Nikolaos Triantafyllou</a>, <a href="/search/astro-ph?searchtype=author&query=Vervelaki%2C+A">Anna Vervelaki</a> , et al. (112 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="2411.16868v1-abstract-short" style="display: inline;"> The X-ray polarization observations made possible with the Imaging X-ray Polarimetry Explorer (IXPE) offer new ways of probing high-energy emission processes in astrophysical jets from blazars. Here we report on the first X-ray polarization observation of the blazar S4 0954+65 in a high optical and X-ray state. During our multi-wavelength campaign on the source, we detected an optical flare whose… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.16868v1-abstract-full').style.display = 'inline'; document.getElementById('2411.16868v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.16868v1-abstract-full" style="display: none;"> The X-ray polarization observations made possible with the Imaging X-ray Polarimetry Explorer (IXPE) offer new ways of probing high-energy emission processes in astrophysical jets from blazars. Here we report on the first X-ray polarization observation of the blazar S4 0954+65 in a high optical and X-ray state. During our multi-wavelength campaign on the source, we detected an optical flare whose peak coincided with the peak of an X-ray flare. This optical-X-ray flare most likely took place in a feature moving along the parsec-scale jet, imaged at 43 GHz by the Very Long Baseline Array. The 43 GHz polarization angle of the moving component underwent a rotation near the time of the flare. In the optical band, prior to the IXPE observation, we measured the polarization angle to be aligned with the jet axis. In contrast, during the optical flare the optical polarization angle was perpendicular to the jet axis; after the flare, it reverted to being parallel to the jet axis. Due to the smooth behavior of the optical polarization angle during the flare, we favor shocks as the main acceleration mechanism. We also infer that the ambient magnetic field lines in the jet were parallel to the jet position angle. The average degree of optical polarization during the IXPE observation was (14.3$\pm$4.1)%. Despite the flare, we only detected an upper limit of 14% (at 3$蟽$ level) on the X-ray polarization degree; although a reasonable assumption on the X-ray polarization angle results in an upper limit of 8.8% ($3蟽$). We model the spectral energy distribution (SED) and spectral polarization distribution (SPD) of S4 0954+65 with leptonic (synchrotron self-Compton) and hadronic (proton and pair synchrotron) models. The constraints we obtain with our combined multi-wavelength polarization observations and SED modeling tentatively disfavor hadronic models for the X-ray emission in S4 0954+65. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.16868v1-abstract-full').style.display = 'none'; document.getElementById('2411.16868v1-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 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">Submitted to A&A, 16 pages, 5 figures, and 7 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/2410.23140">arXiv:2410.23140</a> <span> [<a href="https://arxiv.org/pdf/2410.23140">pdf</a>, <a href="https://arxiv.org/format/2410.23140">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"> Insights from the first flaring activity of a high-synchrotron-peaked blazar with X-ray polarization and VHE gamma rays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abe%2C+K">K. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhir%2C+J">J. Abhir</a>, <a href="/search/astro-ph?searchtype=author&query=Abhishek%2C+A">A. Abhishek</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">A. Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=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=Barrios-Jim%C3%A9nez%2C+L">L. Barrios-Jim茅nez</a>, <a href="/search/astro-ph?searchtype=author&query=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernete%2C+J">J. Bernete</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a> , et al. (228 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="2410.23140v1-abstract-short" style="display: inline;"> We study a flaring activity of the HSP Mrk421 that was characterized from radio to very-high-energy (VHE; E $>0.1$TeV) gamma rays with MAGIC, Fermi-LAT, Swift, XMM-Newton and several optical and radio telescopes. These observations included, for the first time for a gamma-ray flare of a blazar, simultaneous X-ray polarization measurements with IXPE. We find substantial variability in both X-rays a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23140v1-abstract-full').style.display = 'inline'; document.getElementById('2410.23140v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.23140v1-abstract-full" style="display: none;"> We study a flaring activity of the HSP Mrk421 that was characterized from radio to very-high-energy (VHE; E $>0.1$TeV) gamma rays with MAGIC, Fermi-LAT, Swift, XMM-Newton and several optical and radio telescopes. These observations included, for the first time for a gamma-ray flare of a blazar, simultaneous X-ray polarization measurements with IXPE. We find substantial variability in both X-rays and VHE gamma rays throughout the campaign, with the highest VHE flux above 0.2 TeV occurring during the IXPE observing window, and exceeding twice the flux of the Crab Nebula. However, the VHE and X-ray spectra are on average softer, and the correlation between these two bands weaker that those reported in previous flares of Mrk421. IXPE reveals an X-ray polarization degree significantly higher than that at radio and optical frequencies. The X-ray polarization angle varies by $\sim$100$^\circ$ on timescales of days, and the polarization degree changes by more than a factor 4. The highest X-ray polarization degree reaches 26%, around which a X-ray counter-clockwise hysteresis loop is measured with XMM-Newton. It suggests that the X-ray emission comes from particles close to the high-energy cutoff, hence possibly probing an extreme case of the Turbulent Extreme Multi-Zone model. We model the broadband emission with a simplified stratified jet model throughout the flare. The polarization measurements imply an electron distribution in the X-ray emitting region with a very high minimum Lorentz factor, which is expected in electron-ion plasma, as well as a variation of the emitting region size up to a factor of three during the flaring activity. We find no correlation between the fluxes and the evolution of the model parameters, which indicates a stochastic nature of the underlying physical mechanism. Such behaviour would be expected in a highly turbulent electron-ion plasma crossing a shock front. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23140v1-abstract-full').style.display = 'none'; document.getElementById('2410.23140v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">Submitted to Astronomy and Astrophysics. Corresponding authors: Axel Arbet-Engels, Lea Heckmann, David Paneque</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.22557">arXiv:2410.22557</a> <span> [<a href="https://arxiv.org/pdf/2410.22557">pdf</a>, <a href="https://arxiv.org/format/2410.22557">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"> Multi-wavelength study of OT 081: broadband modelling of a transitional blazar </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=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Bernete%2C+J">J. Bernete</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</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> , et al. (250 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="2410.22557v2-abstract-short" style="display: inline;"> OT 081 is a well-known, luminous blazar that is remarkably variable in many energy bands. We present the first broadband study of the source which includes very-high-energy (VHE, $E>$100\,GeV) $纬$-ray data taken by the MAGIC and H.E.S.S. imaging Cherenkov telescopes. The discovery of VHE $纬$-ray emission happened during a high state of $纬$-ray activity in July 2016, observed by many instruments fr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.22557v2-abstract-full').style.display = 'inline'; document.getElementById('2410.22557v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.22557v2-abstract-full" style="display: none;"> OT 081 is a well-known, luminous blazar that is remarkably variable in many energy bands. We present the first broadband study of the source which includes very-high-energy (VHE, $E>$100\,GeV) $纬$-ray data taken by the MAGIC and H.E.S.S. imaging Cherenkov telescopes. The discovery of VHE $纬$-ray emission happened during a high state of $纬$-ray activity in July 2016, observed by many instruments from radio to VHE $纬$-rays. We identify four states of activity of the source, one of which includes VHE $纬$-ray emission. Variability in the VHE domain is found on daily timescales. The intrinsic VHE spectrum can be described by a power-law with index $3.27\pm0.44_{\rm stat}\pm0.15_{\rm sys}$ (MAGIC) and $3.39\pm0.58_{\rm stat}\pm0.64_{\rm sys}$ (H.E.S.S.) in the energy range of 55--300\,GeV and 120--500\,GeV, respectively. The broadband emission cannot be sucessfully reproduced by a simple one-zone synchrotron self-Compton model. Instead, an additional external Compton component is required. We test a lepto-hadronic model that reproduces the dataset well and a proton-synchrotron dominated model that requires an extreme proton luminosity. Emission models that are able to successfully represent the data place the emitting region well outside of the Broad Line Region (BLR) to a location at which the radiative environment is dominated by the infrared thermal radiation field of the dusty torus. In the scenario described by this flaring activity, the source appears to be an FSRQ, in contrast with past categorizations. This suggests that the source can be considered to be a transitional blazar, intermediate between BL~Lac and FSRQ objects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.22557v2-abstract-full').style.display = 'none'; document.getElementById('2410.22557v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">Accepted on MNRAS Corresponding authors: M. Manganaro, J. Becerra Gonz谩lez, M. Seglar-Arroyo, D. A. Sanchez</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.22319">arXiv:2410.22319</a> <span> [<a href="https://arxiv.org/pdf/2410.22319">pdf</a>, <a href="https://arxiv.org/format/2410.22319">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202452311">10.1051/0004-6361/202452311 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A wiggling filamentary jet at the origin of the blazar multi-wavelength behaviour </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Raiteri%2C+C+M">C. M. Raiteri</a>, <a href="/search/astro-ph?searchtype=author&query=Villata%2C+M">M. Villata</a>, <a href="/search/astro-ph?searchtype=author&query=Carnerero%2C+M+I">M. I. Carnerero</a>, <a href="/search/astro-ph?searchtype=author&query=Kurtanidze%2C+S+O">S. O. Kurtanidze</a>, <a href="/search/astro-ph?searchtype=author&query=Mirzaqulov%2C+D+O">D. O. Mirzaqulov</a>, <a href="/search/astro-ph?searchtype=author&query=Ben%C3%ADtez%2C+E">E. Ben铆tez</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">G. Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Carosati%2C+D">D. Carosati</a>, <a href="/search/astro-ph?searchtype=author&query=Acosta-Pulido%2C+J+A">J. A. Acosta-Pulido</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Andreeva%2C+T+S">T. S. Andreeva</a>, <a href="/search/astro-ph?searchtype=author&query=Apolonio%2C+G">G. Apolonio</a>, <a href="/search/astro-ph?searchtype=author&query=Bachev%2C+R">R. Bachev</a>, <a href="/search/astro-ph?searchtype=author&query=Borman%2C+G+A">G. A. Borman</a>, <a href="/search/astro-ph?searchtype=author&query=Bozhilov%2C+V">V. Bozhilov</a>, <a href="/search/astro-ph?searchtype=author&query=Brown%2C+L+F">L. F. Brown</a>, <a href="/search/astro-ph?searchtype=author&query=Carbonell%2C+W">W. Carbonell</a>, <a href="/search/astro-ph?searchtype=author&query=Casadio%2C+C">C. Casadio</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+W+P">W. P. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Damljanovic%2C+G">G. Damljanovic</a>, <a href="/search/astro-ph?searchtype=author&query=Ehgamberdiev%2C+S+A">S. A. Ehgamberdiev</a>, <a href="/search/astro-ph?searchtype=author&query=Elsaesser%2C+D">D. Elsaesser</a>, <a href="/search/astro-ph?searchtype=author&query=Escudero%2C+J">J. Escudero</a>, <a href="/search/astro-ph?searchtype=author&query=Feige%2C+M">M. Feige</a>, <a href="/search/astro-ph?searchtype=author&query=Fuentes%2C+A">A. Fuentes</a> , et al. (74 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="2410.22319v1-abstract-short" style="display: inline;"> Blazars are beamed active galactic nuclei known for their strong multi-wavelength variability on timescales from years down to minutes. We aim to investigate the suitability of the twisting jet model presented in previous works to explain the multi-wavelength behaviour of BL Lacertae, the prototype of one of the blazar classes. According to this model, the jet is inhomogeneous, curved, and twistin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.22319v1-abstract-full').style.display = 'inline'; document.getElementById('2410.22319v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.22319v1-abstract-full" style="display: none;"> Blazars are beamed active galactic nuclei known for their strong multi-wavelength variability on timescales from years down to minutes. We aim to investigate the suitability of the twisting jet model presented in previous works to explain the multi-wavelength behaviour of BL Lacertae, the prototype of one of the blazar classes. According to this model, the jet is inhomogeneous, curved, and twisting, and the long-term variability is due to changes in the Doppler factor due to variations in the orientation of the jet-emitting regions. We analysed optical data of the source obtained during monitoring campaigns organised by the Whole Earth Blazar Telescope (WEBT) in 2019-2022, together with radio data from the WEBT and other teams, and gamma-ray data from the Fermi satellite. In this period, BL Lacertae underwent an extraordinary activity phase, reaching its historical optical and gamma-ray brightness maxima. The application of the twisting jet model to the source light curves allows us to infer the wiggling motion of the optical, radio, and gamma-ray jet-emitting regions. The optical-radio correlation shows that the changes in the radio viewing angle follow those in the optical viewing angle by about 120 days, and it suggests that the jet is composed of plasma filaments, which is in agreement with some radio high-resolution observations of other sources. The gamma-ray emitting region is found to be co-spatial with the optical one, and the analysis of the gamma-optical correlation is consistent with both the geometric interpretation and a synchrotron self-Compton (SSC) origin of the high-energy photons. We propose a geometric scenario where the jet is made up of a pair of emitting plasma filaments in a sort of double-helix curved rotating structure, whose wiggling motion produces changes in the Doppler beaming and can thus explain the observed multi-wavelength long-term variability. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.22319v1-abstract-full').style.display = 'none'; document.getElementById('2410.22319v1-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> 29 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">In press for 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 692 (2024) A48 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.19983">arXiv:2410.19983</a> <span> [<a href="https://arxiv.org/pdf/2410.19983">pdf</a>, <a href="https://arxiv.org/format/2410.19983">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"> A Two-Week $IXPE$ Monitoring Campaign on Mrk 421 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Maksym%2C+W+P">W. Peter Maksym</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Saade%2C+M+L">M. Lynne Saade</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+E">Dawoon E. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Kiehlmann%2C+S">Sebastian Kiehlmann</a>, <a href="/search/astro-ph?searchtype=author&query=Matzeu%2C+G">Gabriele Matzeu</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Ehlert%2C+S+R">Steven R. Ehlert</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Kaaret%2C+P">Philip Kaaret</a>, <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Pacciani%2C+L">Luigi Pacciani</a>, <a href="/search/astro-ph?searchtype=author&query=Perri%2C+M">Matteo Perri</a>, <a href="/search/astro-ph?searchtype=author&query=Puccetti%2C+S">Simonetta Puccetti</a>, <a href="/search/astro-ph?searchtype=author&query=Kouch%2C+P+M">Pouya M. Kouch</a>, <a href="/search/astro-ph?searchtype=author&query=Lindfors%2C+E">Elina Lindfors</a>, <a href="/search/astro-ph?searchtype=author&query=Aceituno%2C+F+J">Francisco Jos茅 Aceituno</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Casanova%2C+V">V铆ctor Casanova</a>, <a href="/search/astro-ph?searchtype=author&query=Escudero%2C+J">Juan Escudero</a>, <a href="/search/astro-ph?searchtype=author&query=Ag%C3%ADs-Gonz%C3%A1lez%2C+B">Beatriz Ag铆s-Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Husillos%2C+C">C茅sar Husillos</a> , et al. (131 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="2410.19983v1-abstract-short" style="display: inline;"> X-ray polarization is a unique new probe of the particle acceleration in astrophysical jets made possible through the Imaging X-ray Polarimetry Explorer. Here we report on the first dense X-ray polarization monitoring campaign on the blazar Mrk 421. Our observations were accompanied by an even denser radio and optical polarization campaign. We find significant short-timescale variability in both X… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.19983v1-abstract-full').style.display = 'inline'; document.getElementById('2410.19983v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.19983v1-abstract-full" style="display: none;"> X-ray polarization is a unique new probe of the particle acceleration in astrophysical jets made possible through the Imaging X-ray Polarimetry Explorer. Here we report on the first dense X-ray polarization monitoring campaign on the blazar Mrk 421. Our observations were accompanied by an even denser radio and optical polarization campaign. We find significant short-timescale variability in both X-ray polarization degree and angle, including a $\sim90^\circ$ angle rotation about the jet axis. We attribute this to random variations of the magnetic field, consistent with the presence of turbulence but also unlikely to be explained by turbulence alone. At the same time, the degree of lower-energy polarization is significantly lower and shows no more than mild variability. Our campaign provides further evidence for a scenario in which energy-stratified shock-acceleration of relativistic electrons, combined with a turbulent magnetic field, is responsible for optical to X-ray synchrotron emission in blazar jets. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.19983v1-abstract-full').style.display = 'none'; document.getElementById('2410.19983v1-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">23 pages, including 8 pages of appendices. 12 figures, 3 tables. 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/2410.16042">arXiv:2410.16042</a> <span> [<a href="https://arxiv.org/pdf/2410.16042">pdf</a>, <a href="https://arxiv.org/format/2410.16042">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/10.1051/0004-6361/202450889">10.1051/0004-6361/202450889 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A new method of reconstructing images of gamma-ray telescopes applied to the LST-1 of CTAO </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Project%2C+C">CTA-LST Project</a>, <a href="/search/astro-ph?searchtype=author&query=%3A"> :</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+K">K. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhishek%2C+A">A. Abhishek</a>, <a href="/search/astro-ph?searchtype=author&query=Acero%2C+F">F. Acero</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">A. Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Alispach%2C+C">C. Alispach</a>, <a href="/search/astro-ph?searchtype=author&query=Crespo%2C+N+A">N. Alvarez Crespo</a>, <a href="/search/astro-ph?searchtype=author&query=Ambrosino%2C+D">D. Ambrosino</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=Aramo%2C+C">C. Aramo</a>, <a href="/search/astro-ph?searchtype=author&query=Arbet-Engels%2C+A">A. Arbet-Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</a>, <a href="/search/astro-ph?searchtype=author&query=Aubert%2C+P">P. Aubert</a>, <a href="/search/astro-ph?searchtype=author&query=Baktash%2C+A">A. Baktash</a>, <a href="/search/astro-ph?searchtype=author&query=Balbo%2C+M">M. Balbo</a>, <a href="/search/astro-ph?searchtype=author&query=Bamba%2C+A">A. Bamba</a>, <a href="/search/astro-ph?searchtype=author&query=Larriva%2C+A+B">A. Baquero Larriva</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=Jim%C3%A9nez%2C+L+B">L. Barrios Jim茅nez</a>, <a href="/search/astro-ph?searchtype=author&query=Batkovic%2C+I">I. Batkovic</a> , et al. (283 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="2410.16042v1-abstract-short" style="display: inline;"> Imaging atmospheric Cherenkov telescopes (IACTs) are used to observe very high-energy photons from the ground. Gamma rays are indirectly detected through the Cherenkov light emitted by the air showers they induce. The new generation of experiments, in particular the Cherenkov Telescope Array Observatory (CTAO), sets ambitious goals for discoveries of new gamma-ray sources and precise measurements… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.16042v1-abstract-full').style.display = 'inline'; document.getElementById('2410.16042v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.16042v1-abstract-full" style="display: none;"> Imaging atmospheric Cherenkov telescopes (IACTs) are used to observe very high-energy photons from the ground. Gamma rays are indirectly detected through the Cherenkov light emitted by the air showers they induce. The new generation of experiments, in particular the Cherenkov Telescope Array Observatory (CTAO), sets ambitious goals for discoveries of new gamma-ray sources and precise measurements of the already discovered ones. To achieve these goals, both hardware and data analysis must employ cutting-edge techniques. This also applies to the LST-1, the first IACT built for the CTAO, which is currently taking data on the Canary island of La Palma. This paper introduces a new event reconstruction technique for IACT data, aiming to improve the image reconstruction quality and the discrimination between the signal and the background from misidentified hadrons and electrons. The technique models the development of the extensive air shower signal, recorded as a waveform per pixel, seen by CTAO telescopes' cameras. Model parameters are subsequently passed to random forest regressors and classifiers to extract information on the primary particle. The new reconstruction was applied to simulated data and to data from observations of the Crab Nebula performed by the LST-1. The event reconstruction method presented here shows promising performance improvements. The angular and energy resolution, and the sensitivity, are improved by 10 to 20% over most of the energy range. At low energy, improvements reach up to 22%, 47%, and 50%, respectively. A future extension of the method to stereoscopic analysis for telescope arrays will be the next important step. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.16042v1-abstract-full').style.display = 'none'; document.getElementById('2410.16042v1-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">Accepted 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 691, A328 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.18823">arXiv:2409.18823</a> <span> [<a href="https://arxiv.org/pdf/2409.18823">pdf</a>, <a href="https://arxiv.org/format/2409.18823">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> <p class="title is-5 mathjax"> Standardised formats and open-source analysis tools for the MAGIC telescopes data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhir%2C+J">J. Abhir</a>, <a href="/search/astro-ph?searchtype=author&query=Abhishek%2C+A">A. Abhishek</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">A. Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Bautista%2C+A">A. Bautista</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernete%2C+J">J. Bernete</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a> , et al. (186 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="2409.18823v2-abstract-short" style="display: inline;"> Instruments for gamma-ray astronomy at Very High Energies ($E>100\,{\rm GeV}$) have traditionally derived their scientific results through proprietary data and software. Data standardisation has become a prominent issue in this field both as a requirement for the dissemination of data from the next generation of gamma-ray observatories and as an effective solution to realise public data legacies o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.18823v2-abstract-full').style.display = 'inline'; document.getElementById('2409.18823v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.18823v2-abstract-full" style="display: none;"> Instruments for gamma-ray astronomy at Very High Energies ($E>100\,{\rm GeV}$) have traditionally derived their scientific results through proprietary data and software. Data standardisation has become a prominent issue in this field both as a requirement for the dissemination of data from the next generation of gamma-ray observatories and as an effective solution to realise public data legacies of current-generation instruments. Specifications for a standardised gamma-ray data format have been proposed as a community effort and have already been successfully adopted by several instruments. We present the first production of standardised data from the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes. We converted $166\,{\rm h}$ of observations from different sources and validated their analysis with the open-source software Gammapy. We consider six data sets representing different scientific and technical analysis cases and compare the results obtained analysing the standardised data with open-source software against those produced with the MAGIC proprietary data and software. Aiming at a systematic production of MAGIC data in this standardised format, we also present the implementation of a database-driven pipeline automatically performing the MAGIC data reduction from the calibrated down to the standardised data level. In all the cases selected for the validation, we obtain results compatible with the MAGIC proprietary software, both for the manual and for the automatic data productions. Part of the validation data set is also made publicly available, thus representing the first large public release of MAGIC data. This effort and this first data release represent a technical milestone toward the realisation of a public MAGIC data legacy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.18823v2-abstract-full').style.display = 'none'; document.getElementById('2409.18823v2-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> 7 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 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">Accepted for publication in the Journal of High Energy Astrophysics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.11128">arXiv:2407.11128</a> <span> [<a href="https://arxiv.org/pdf/2407.11128">pdf</a>, <a href="https://arxiv.org/format/2407.11128">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> <p class="title is-5 mathjax"> X-ray and multiwavelength polarization of Mrk 501 from 2022 to 2023 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chen%2C+C+J">Chien-Ting J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+E">Dawoon E. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Marco%2C+A">Alessandro Di Marco</a>, <a href="/search/astro-ph?searchtype=author&query=Ehlert%2C+S+R">Steven R. Ehlert</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">Manel Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Negro%2C+M">Michela Negro</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Wu%2C+K">Kinwah Wu</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Poutanen%2C+J">Juri Poutanen</a>, <a href="/search/astro-ph?searchtype=author&query=Mizuno%2C+T">Tsunefumi Mizuno</a>, <a href="/search/astro-ph?searchtype=author&query=Kouch%2C+P+M">Pouya M. Kouch</a>, <a href="/search/astro-ph?searchtype=author&query=Lindfors%2C+E">Elina Lindfors</a>, <a href="/search/astro-ph?searchtype=author&query=Borman%2C+G+A">George A. Borman</a>, <a href="/search/astro-ph?searchtype=author&query=Grishina%2C+T+S">Tatiana S. Grishina</a>, <a href="/search/astro-ph?searchtype=author&query=Kopatskaya%2C+E+N">Evgenia N. Kopatskaya</a>, <a href="/search/astro-ph?searchtype=author&query=Larionova%2C+E+G">Elena G. Larionova</a>, <a href="/search/astro-ph?searchtype=author&query=Morozova%2C+D+A">Daria A. Morozova</a>, <a href="/search/astro-ph?searchtype=author&query=Savchenko%2C+S+S">Sergey S. Savchenko</a>, <a href="/search/astro-ph?searchtype=author&query=Troitsky%2C+I+S">Ivan S. Troitsky</a>, <a href="/search/astro-ph?searchtype=author&query=Troitskaya%2C+Y+V">Yulia V. Troitskaya</a> , et al. (121 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="2407.11128v1-abstract-short" style="display: inline;"> We present multiwavelength polarization measurements of the luminous blazar Mrk~501 over a 14-month period. The 2--8 keV X-ray polarization was measured with the Imaging X-ray Polarimetry Explorer (IXPE) with six 100-ks observations spanning from 2022 March to 2023 April. Each IXPE observation was accompanied by simultaneous X-ray data from NuSTAR, Swift/XRT, and/or XMM-Newton. Complementary optic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.11128v1-abstract-full').style.display = 'inline'; document.getElementById('2407.11128v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.11128v1-abstract-full" style="display: none;"> We present multiwavelength polarization measurements of the luminous blazar Mrk~501 over a 14-month period. The 2--8 keV X-ray polarization was measured with the Imaging X-ray Polarimetry Explorer (IXPE) with six 100-ks observations spanning from 2022 March to 2023 April. Each IXPE observation was accompanied by simultaneous X-ray data from NuSTAR, Swift/XRT, and/or XMM-Newton. Complementary optical-infrared polarization measurements were also available in the B, V, R, I, and J bands, as were radio polarization measurements from 4.85 GHz to 225.5 GHz. Among the first five IXPE observations, we did not find significant variability in the X-ray polarization degree and angle with IXPE. However, the most recent sixth observation found an elevated polarization degree at $>3蟽$ above the average of the other five observations. The optical and radio measurements show no apparent correlations with the X-ray polarization properties. Throughout the six IXPE observations, the X-ray polarization degree remained higher than, or similar to, the R-band optical polarization degree, which remained higher than the radio value. This is consistent with the energy-stratified shock scenario proposed to explain the first two IXPE observations, in which the polarized X-ray, optical, and radio emission arises from different regions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.11128v1-abstract-full').style.display = 'none'; document.getElementById('2407.11128v1-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.06961">arXiv:2407.06961</a> <span> [<a href="https://arxiv.org/pdf/2407.06961">pdf</a>, <a href="https://arxiv.org/format/2407.06961">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"> Combined Fit of Spectrum and Composition for FR0 Radio Galaxy Emitted Ultra-High-Energy Cosmic Rays with Resulting Secondary Photons and Neutrinos </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lundquist%2C+J+P">Jon Paul Lundquist</a>, <a href="/search/astro-ph?searchtype=author&query=Vorobiov%2C+S">Serguei Vorobiov</a>, <a href="/search/astro-ph?searchtype=author&query=Merten%2C+L">Lukas Merten</a>, <a href="/search/astro-ph?searchtype=author&query=Reimer%2C+A">Anita Reimer</a>, <a href="/search/astro-ph?searchtype=author&query=Boughelilba%2C+M">Margot Boughelilba</a>, <a href="/search/astro-ph?searchtype=author&query=Da+Vela%2C+P">Paolo Da Vela</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">Fabrizio Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Righi%2C+C">Chiara Righi</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="2407.06961v1-abstract-short" style="display: inline;"> This study comprehensively investigates the gamma-ray dim population of Fanaroff-Riley Type 0 (FR0) radio galaxies as potentially significant sources of ultra-high-energy cosmic rays (UHECRs, E $>$ 10$^{18}$ eV) detected on Earth. While individual FR0 luminosities are relatively low compared to the more powerful Fanaroff-Riley Type 1 and Type 2 galaxies, FR0s are substantially more prevalent in th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.06961v1-abstract-full').style.display = 'inline'; document.getElementById('2407.06961v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.06961v1-abstract-full" style="display: none;"> This study comprehensively investigates the gamma-ray dim population of Fanaroff-Riley Type 0 (FR0) radio galaxies as potentially significant sources of ultra-high-energy cosmic rays (UHECRs, E $>$ 10$^{18}$ eV) detected on Earth. While individual FR0 luminosities are relatively low compared to the more powerful Fanaroff-Riley Type 1 and Type 2 galaxies, FR0s are substantially more prevalent in the local universe, outnumbering the more energetic galaxies by a factor of $\sim$5 within a redshift of z $\leq$ 0.05. Employing CRPropa3 simulations, we estimate the mass composition and energy spectra of UHECRs originating from FR0 galaxies for energies above 10$^{18.6}$ eV. This estimation fits data from the Pierre Auger Observatory (Auger) using three extensive air shower models; both constant and energy-dependent observed elemental fractions are considered. The simulation integrates an isotropic distribution of FR0 galaxies, extrapolated from observed characteristics, with UHECR propagation in the intergalactic medium, incorporating various plausible configurations of extragalactic magnetic fields, both random and structured. We then compare the resulting emission spectral indices, rigidity cutoffs, and elemental fractions with recent Auger results. In total, 25 combined energy spectrum and mass composition fits are considered. Beyond the cosmic ray fluxes emitted by FR0 galaxies, this study predicts the secondary photon and neutrino fluxes from UHECR interactions with intergalactic cosmic photon backgrounds. The multi-messenger approach, encompassing observational data and theoretical models, helps elucidate the contribution of low luminosity FR0 radio galaxies to the total cosmic ray energy density. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.06961v1-abstract-full').style.display = 'none'; document.getElementById('2407.06961v1-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">To be submitted to The Astrophysical Journal. 22 pages, 16 figures, 6 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.02343">arXiv:2407.02343</a> <span> [<a href="https://arxiv.org/pdf/2407.02343">pdf</a>, <a href="https://arxiv.org/format/2407.02343">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"> A detailed study of the very-high-energy Crab pulsar emission with the LST-1 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Project%2C+C">CTA-LST Project</a>, <a href="/search/astro-ph?searchtype=author&query=%3A"> :</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+K">K. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhishek%2C+A">A. Abhishek</a>, <a href="/search/astro-ph?searchtype=author&query=Acero%2C+F">F. Acero</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">A. Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Crespo%2C+N+A">N. Alvarez Crespo</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=Aramo%2C+C">C. Aramo</a>, <a href="/search/astro-ph?searchtype=author&query=Arbet-Engels%2C+A">A. Arbet-Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</a>, <a href="/search/astro-ph?searchtype=author&query=Aubert%2C+P">P. Aubert</a>, <a href="/search/astro-ph?searchtype=author&query=Baktash%2C+A">A. Baktash</a>, <a href="/search/astro-ph?searchtype=author&query=Bamba%2C+A">A. Bamba</a>, <a href="/search/astro-ph?searchtype=author&query=Larriva%2C+A+B">A. Baquero Larriva</a>, <a href="/search/astro-ph?searchtype=author&query=Baroncelli%2C+L">L. Baroncelli</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=Batkovic%2C+I">I. Batkovic</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</a>, <a href="/search/astro-ph?searchtype=author&query=Gonz%C3%A1lez%2C+J+B">J. Becerra Gonz谩lez</a> , et al. (272 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="2407.02343v1-abstract-short" style="display: inline;"> Context: There are currently three pulsars firmly detected by imaging atmospheric Cherenkov telescopes (IACTs), two of them reaching TeV energies, challenging models of very-high-energy (VHE) emission in pulsars. More precise observations are needed to better characterize pulsar emission at these energies. The LST-1 is the prototype of the Large-Sized Telescope, that will be part of the Cherenkov… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.02343v1-abstract-full').style.display = 'inline'; document.getElementById('2407.02343v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.02343v1-abstract-full" style="display: none;"> Context: There are currently three pulsars firmly detected by imaging atmospheric Cherenkov telescopes (IACTs), two of them reaching TeV energies, challenging models of very-high-energy (VHE) emission in pulsars. More precise observations are needed to better characterize pulsar emission at these energies. The LST-1 is the prototype of the Large-Sized Telescope, that will be part of the Cherenkov Telescope Array Observatory (CTAO). Its improved performance over previous IACTs makes it well suited for studying pulsars. Aims: To study the Crab pulsar emission with the LST-1, improving and complementing the results from other telescopes. These observations can also be used to characterize the potential of the LST-1 to study other pulsars and detect new ones. Methods: We analyzed a total of $\sim$103 hours of gamma-ray observations of the Crab pulsar conducted with the LST-1 in the period from September 2020 to January 2023. The observations were carried out at zenith angles less than 50 degrees. A new analysis of the Fermi-LAT data was also performed, including $\sim$14 years of observations. Results: The Crab pulsar phaseogram, long-term light-curve, and phase-resolved spectra are reconstructed with the LST-1 from 20 GeV to 450 GeV for P1 and up to 700 GeV for P2. The pulsed emission is detected with a significance of 15.2$蟽$. The two characteristic emission peaks of the Crab pulsar are clearly detected (>10$蟽$), as well as the so-called bridge emission (5.7$蟽$). We find that both peaks are well described by power laws, with spectral indices of $\sim$3.44 and $\sim$3.03 respectively. The joint analysis of Fermi-LAT and LST-1 data shows a good agreement between both instruments in the overlapping energy range. The detailed results obtained in the first observations of the Crab pulsar with LST-1 show the potential that CTAO will have to study this type of sources. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.02343v1-abstract-full').style.display = 'none'; document.getElementById('2407.02343v1-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">Accepted by A&A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.15554">arXiv:2406.15554</a> <span> [<a href="https://arxiv.org/pdf/2406.15554">pdf</a>, <a href="https://arxiv.org/format/2406.15554">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202451037">10.1051/0004-6361/202451037 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Testing particle acceleration in blazar jets with continuous high-cadence optical polarization observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Kiehlmann%2C+S">Sebastian Kiehlmann</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+H">Haocheng Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Blinov%2C+D">Dmitry Blinov</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Ben%C3%ADtez%2C+E">Erika Ben铆tez</a>, <a href="/search/astro-ph?searchtype=author&query=Berdyugin%2C+A">Andrei Berdyugin</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Casadio%2C+C">Carolina Casadio</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+C">Chien-Ting Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+W">Wen-Ping Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Ehlert%2C+S+R">Steven R. Ehlert</a>, <a href="/search/astro-ph?searchtype=author&query=Escudero%2C+J">Juan Escudero</a>, <a href="/search/astro-ph?searchtype=author&query=Grishina%2C+T+S">Tatiana S. Grishina</a>, <a href="/search/astro-ph?searchtype=author&query=Hiriart%2C+D">David Hiriart</a>, <a href="/search/astro-ph?searchtype=author&query=Hsu%2C+A">Angela Hsu</a>, <a href="/search/astro-ph?searchtype=author&query=Imazawa%2C+R">Ryo Imazawa</a>, <a href="/search/astro-ph?searchtype=author&query=Jermak%2C+H+E">Helen E. Jermak</a>, <a href="/search/astro-ph?searchtype=author&query=Jose%2C+J">Jincen Jose</a>, <a href="/search/astro-ph?searchtype=author&query=Kaaret%2C+P">Philip Kaaret</a>, <a href="/search/astro-ph?searchtype=author&query=Kopatskaya%2C+E+N">Evgenia N. Kopatskaya</a>, <a href="/search/astro-ph?searchtype=author&query=Lalchand%2C+B">Bhavana Lalchand</a>, <a href="/search/astro-ph?searchtype=author&query=Larionova%2C+E+G">Elena G. Larionova</a> , et al. (22 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="2406.15554v1-abstract-short" style="display: inline;"> Variability can be the pathway to understanding the physical processes in astrophysical jets, however, the high-cadence observations required to test particle acceleration models are still missing. Here we report on the first attempt to produce continuous, >24 hour polarization light curves of blazars using telescopes distributed across the globe and the rotation of the Earth to avoid the rising S… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.15554v1-abstract-full').style.display = 'inline'; document.getElementById('2406.15554v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.15554v1-abstract-full" style="display: none;"> Variability can be the pathway to understanding the physical processes in astrophysical jets, however, the high-cadence observations required to test particle acceleration models are still missing. Here we report on the first attempt to produce continuous, >24 hour polarization light curves of blazars using telescopes distributed across the globe and the rotation of the Earth to avoid the rising Sun. Our campaign involved 16 telescopes in Asia, Europe, and North America. We observed BL Lacertae and CGRaBS J0211+1051 for a combined 685 telescope hours. We find large variations in the polarization degree and angle for both sources in sub-hour timescales as well as a ~180 degree rotation of the polarization angle in CGRaBS J0211+1051 in less than two days. We compared our high-cadence observations to Particle-In-Cell magnetic reconnection and turbulent plasma simulations. We find that although the state of the art simulation frameworks can produce a large fraction of the polarization properties, they do not account for the entirety of the observed polarization behavior in blazar jets. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.15554v1-abstract-full').style.display = 'none'; document.getElementById('2406.15554v1-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 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">20 pages, 15 figures, 2 tables, accepted for publication in A&A. The data used in the paper are available here: https://doi.org/10.7910/DVN/IETSXS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 689, A200 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.07140">arXiv:2406.07140</a> <span> [<a href="https://arxiv.org/pdf/2406.07140">pdf</a>, <a href="https://arxiv.org/format/2406.07140">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> <p class="title is-5 mathjax"> Constraints on Lorentz invariance violation from the extraordinary Mrk 421 flare of 2014 using a novel analysis method </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=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhir%2C+J">J. Abhir</a>, <a href="/search/astro-ph?searchtype=author&query=Abhishek%2C+A">A. Abhishek</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">A. Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Bautista%2C+A">A. Bautista</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernete%2C+J">J. Bernete</a> , et al. (192 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="2406.07140v1-abstract-short" style="display: inline;"> The Lorentz Invariance Violation (LIV), a proposed consequence of certain quantum gravity (QG) scenarios, could instigate an energy-dependent group velocity for ultra-relativistic particles. This energy dependence, although suppressed by the massive QG energy scale $E_\mathrm{QG}$, expected to be on the level of the Planck energy $1.22 \times 10^{19}$ GeV, is potentially detectable in astrophysica… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.07140v1-abstract-full').style.display = 'inline'; document.getElementById('2406.07140v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.07140v1-abstract-full" style="display: none;"> The Lorentz Invariance Violation (LIV), a proposed consequence of certain quantum gravity (QG) scenarios, could instigate an energy-dependent group velocity for ultra-relativistic particles. This energy dependence, although suppressed by the massive QG energy scale $E_\mathrm{QG}$, expected to be on the level of the Planck energy $1.22 \times 10^{19}$ GeV, is potentially detectable in astrophysical observations. In this scenario, the cosmological distances traversed by photons act as an amplifier for this effect. By leveraging the observation of a remarkable flare from the blazar Mrk\,421, recorded at energies above 100 GeV by the MAGIC telescopes on the night of April 25 to 26, 2014, we look for time delays scaling linearly and quadratically with the photon energies. Using for the first time in LIV studies a binned-likelihood approach we set constraints on the QG energy scale. For the linear scenario, we set $95\%$ lower limits $E_\mathrm{QG}>2.7\times10^{17}$ GeV for the subluminal case and $E_\mathrm{QG}> 3.6 \times10^{17}$ GeV for the superluminal case. For the quadratic scenario, the $95\%$ lower limits for the subluminal and superluminal cases are $E_\mathrm{QG}>2.6 \times10^{10}$ GeV and $E_\mathrm{QG}>2.5\times10^{10}$ GeV, respectively. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.07140v1-abstract-full').style.display = 'none'; document.getElementById('2406.07140v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.01693">arXiv:2406.01693</a> <span> [<a href="https://arxiv.org/pdf/2406.01693">pdf</a>, <a href="https://arxiv.org/format/2406.01693">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202449166">10.1051/0004-6361/202449166 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> IXPE observation of PKS 2155-304 reveals the most highly polarized blazar </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kouch%2C+P+M">Pouya M. Kouch</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+E">Dawoon E. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">Fabrizio Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Ehlert%2C+S+R">Steven R. Ehlert</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Madejski%2C+G+M">Grzegorz M. Madejski</a>, <a href="/search/astro-ph?searchtype=author&query=Romani%2C+R+W">Roger W. Romani</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">Manel Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Lindfors%2C+E">Elina Lindfors</a>, <a href="/search/astro-ph?searchtype=author&query=Nilsson%2C+K">Kari Nilsson</a>, <a href="/search/astro-ph?searchtype=author&query=Toppari%2C+E">Ella Toppari</a>, <a href="/search/astro-ph?searchtype=author&query=Potter%2C+S+B">Stephen B. Potter</a>, <a href="/search/astro-ph?searchtype=author&query=Imazawa%2C+R">Ryo Imazawa</a>, <a href="/search/astro-ph?searchtype=author&query=Sasada%2C+M">Mahito Sasada</a>, <a href="/search/astro-ph?searchtype=author&query=Fukazawa%2C+Y">Yasushi Fukazawa</a>, <a href="/search/astro-ph?searchtype=author&query=Kawabata%2C+K+S">Koji S. Kawabata</a>, <a href="/search/astro-ph?searchtype=author&query=Uemura%2C+M">Makoto Uemura</a>, <a href="/search/astro-ph?searchtype=author&query=Mizuno%2C+T">Tsunefumi Mizuno</a>, <a href="/search/astro-ph?searchtype=author&query=Nakaoka%2C+T">Tatsuya Nakaoka</a> , et al. (111 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="2406.01693v1-abstract-short" style="display: inline;"> We report the X-ray polarization properties of the high-synchrotron-peaked (HSP) blazar PKS 2155$-$304 based on observations with the Imaging X-ray Polarimetry Explorer (IXPE). We observed the source between Oct 27 and Nov 7, 2023. We also conducted an extensive contemporaneous multiwavelength (MW) campaign. We find that during the first half ($T_1$) of the IXPE pointing, the source exhibited the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.01693v1-abstract-full').style.display = 'inline'; document.getElementById('2406.01693v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.01693v1-abstract-full" style="display: none;"> We report the X-ray polarization properties of the high-synchrotron-peaked (HSP) blazar PKS 2155$-$304 based on observations with the Imaging X-ray Polarimetry Explorer (IXPE). We observed the source between Oct 27 and Nov 7, 2023. We also conducted an extensive contemporaneous multiwavelength (MW) campaign. We find that during the first half ($T_1$) of the IXPE pointing, the source exhibited the highest X-ray polarization degree detected for an HSP blazar thus far, (30.7$\pm$2.0)%, which dropped to (15.3$\pm$2.1)% during the second half ($T_2$). The X-ray polarization angle remained stable during the IXPE pointing at 129.4$^\circ$$\pm$1.8$^\circ$ and 125.4$^\circ$$\pm$3.9$^\circ$ during $T_1$ and $T_2$, respectively. Meanwhile, the optical polarization degree remained stable during the IXPE pointing, with average host-galaxy-corrected values of (4.3$\pm$0.7)% and (3.8$\pm$0.9)% during the $T_1$ and $T_2$, respectively. During the IXPE pointing, the optical polarization angle changed achromatically from $\sim$140$^\circ$ to $\sim$90$^\circ$ and back to $\sim$130$^\circ$. Despite several attempts, we only detected (99.7% conf.) the radio polarization once (during $T_2$, at 225.5 GHz): with degree (1.7$\pm$0.4)% and angle 112.5$^\circ$$\pm$5.5$^\circ$. The direction of the broad pc-scale jet is rather ambiguous and has been found to point to the east and south at different epochs; however, on larger scales (> 1.5 pc) the jet points toward the southeast ($\sim$135$^\circ$), similar to all of the MW polarization angles. Moreover, the X-ray to optical polarization degree ratios of $\sim$7 and $\sim$4 during $T_1$ and $T_2$, respectively, are similar to previous IXPE results for several HSP blazars. These findings, combined with the lack of correlation of temporal variability between the MW polarization properties, agree with an energy-stratified shock-acceleration scenario in HSP blazars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.01693v1-abstract-full').style.display = 'none'; document.getElementById('2406.01693v1-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 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">17 pages, 10 figures, 4 tables, 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 689, A119 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.20111">arXiv:2405.20111</a> <span> [<a href="https://arxiv.org/pdf/2405.20111">pdf</a>, <a href="https://arxiv.org/format/2405.20111">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"> IOP4, the Interactive Optical Photo-Polarimetric Python Pipeline </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pedrosa%2C+J+E">Juan Escudero Pedrosa</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Ivan Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Morcuende%2C+D">Daniel Morcuende</a>, <a href="/search/astro-ph?searchtype=author&query=Otero-Santos%2C+J">Jorge Otero-Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Piirola%2C+V">Vilppu Piirola</a>, <a href="/search/astro-ph?searchtype=author&query=Husillos%2C+C">C茅sar Husillos</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M">Mabel Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=L%C3%B3pez-Coto%2C+R">Rub茅n L贸pez-Coto</a>, <a href="/search/astro-ph?searchtype=author&query=Sota%2C+A">Alfredo Sota</a>, <a href="/search/astro-ph?searchtype=author&query=Casanova%2C+V">V铆ctor Casanova</a>, <a href="/search/astro-ph?searchtype=author&query=Aceituno%2C+F">Francisco Aceituno</a>, <a href="/search/astro-ph?searchtype=author&query=Santos-Sanz%2C+P">Pablo Santos-Sanz</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="2405.20111v1-abstract-short" style="display: inline;"> IOP4 is a pipeline to perform photometry and polarimetry analysis of optical data from Calar Alto (CAHA) and Sierra Nevada (OSN) observatories. IOP4 implements Object Relational Mapping (ORM) to seamlessly integrate all information about the reduction and results in a database which can be used to query and plot results, flag data and inspect the reduction process in an integrated fashion with the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20111v1-abstract-full').style.display = 'inline'; document.getElementById('2405.20111v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.20111v1-abstract-full" style="display: none;"> IOP4 is a pipeline to perform photometry and polarimetry analysis of optical data from Calar Alto (CAHA) and Sierra Nevada (OSN) observatories. IOP4 implements Object Relational Mapping (ORM) to seamlessly integrate all information about the reduction and results in a database which can be used to query and plot results, flag data and inspect the reduction process in an integrated fashion with the whole pipeline. It also ships with an already built-in web interface which can be used out of the box to browse the database and supervise all pipeline processes. It is built to ease debugging and inspection of data. Reduction from five different instruments are already implemented: RoperT90, AndorT90 and DIPOL (at OSN 0.9m telescope), AndorT150 (OSN 1.5m telescope) and CAFOS (CAHA 2.2m telescope). IOP4's modular design allows for easy integration of new observatories and instruments, and its results have already featured in several high-impact refereed publications. In this paper we describe the implementation and characteristics of IOP4. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20111v1-abstract-full').style.display = 'none'; document.getElementById('2405.20111v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">Submitted April 23, 2024</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.10141">arXiv:2405.10141</a> <span> [<a href="https://arxiv.org/pdf/2405.10141">pdf</a>, <a href="https://arxiv.org/format/2405.10141">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202449726">10.1051/0004-6361/202449726 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The flaring activity of blazar AO 0235+164 during year 2021 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pedrosa%2C+J+E">Juan Escudero Pedrosa</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Moritz%2C+T">Till Moritz</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S">Svetlana Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Tramacere%2C+A">Andrea Tramacere</a>, <a href="/search/astro-ph?searchtype=author&query=Casadio%2C+C">Carolina Casadio</a>, <a href="/search/astro-ph?searchtype=author&query=Thum%2C+C">Clemens Thum</a>, <a href="/search/astro-ph?searchtype=author&query=Myserlis%2C+I">Ioannis Myserlis</a>, <a href="/search/astro-ph?searchtype=author&query=Sievers%2C+A">Albrecht Sievers</a>, <a href="/search/astro-ph?searchtype=author&query=Otero-Santos%2C+J">Jorge Otero-Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Morcuende%2C+D">Daniel Morcuende</a>, <a href="/search/astro-ph?searchtype=author&query=L%C3%B3pez-Coto%2C+R">Rub茅n L贸pez-Coto</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=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Gurwell%2C+M">Mark Gurwell</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3mez%2C+J+L">Jos茅 Luis G贸mez</a>, <a href="/search/astro-ph?searchtype=author&query=Rao%2C+R">Ramprasad Rao</a>, <a href="/search/astro-ph?searchtype=author&query=Keating%2C+G">Garrett Keating</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="2405.10141v1-abstract-short" style="display: inline;"> Context. The blazar AO 0235+164, located at redshift $z=0.94$, has displayed interesting and repeating flaring activity in the past, the latest episodes occurring in 2008 and 2015. In 2020, the source brightened again, starting a new flaring episode that peaked in 2021. Aims. We study the origin and properties of the 2021 flare in relation to previous studies and the historical behavior of the sou… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.10141v1-abstract-full').style.display = 'inline'; document.getElementById('2405.10141v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.10141v1-abstract-full" style="display: none;"> Context. The blazar AO 0235+164, located at redshift $z=0.94$, has displayed interesting and repeating flaring activity in the past, the latest episodes occurring in 2008 and 2015. In 2020, the source brightened again, starting a new flaring episode that peaked in 2021. Aims. We study the origin and properties of the 2021 flare in relation to previous studies and the historical behavior of the source, in particular to the 2008 and 2015 flaring episodes. Methods. We analyze the multi-wavelength photo-polarimetric evolution of the source. From Very Long Baseline Array images, we derive the kinematic parameters of new components associated with the 2021 flare. We use this information to constrain a model for the spectral energy distribution of the emission during the flaring period. We propose an analytical geometric model to test whether the observed wobbling of the jet is consistent with precession. Results. We report the appearance of two new components that are ejected in a different direction than previously, confirming the wobbling of the jet. We find that the direction of ejection is consistent with that of a precessing jet.The derived period independently agrees with the values commonly found in the literature. Modeling of the spectral energy distribution further confirm that the differences between flares can be attributed to geometrical effects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.10141v1-abstract-full').style.display = 'none'; document.getElementById('2405.10141v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">Accepted 15 May 2024</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 689, A56 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.04857">arXiv:2403.04857</a> <span> [<a href="https://arxiv.org/pdf/2403.04857">pdf</a>, <a href="https://arxiv.org/format/2403.04857">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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/10.1088/1475-7516/2024/07/047">10.1088/1475-7516/2024/07/047 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dark Matter Line Searches with the Cherenkov Telescope Array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhir%2C+J">J. Abhir</a>, <a href="/search/astro-ph?searchtype=author&query=Abhishek%2C+A">A. Abhishek</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=Adam%2C+R">R. Adam</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">A. Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aguirre-Santaella%2C+A">A. Aguirre-Santaella</a>, <a href="/search/astro-ph?searchtype=author&query=Alfaro%2C+J">J. Alfaro</a>, <a href="/search/astro-ph?searchtype=author&query=Alfaro%2C+R">R. Alfaro</a>, <a href="/search/astro-ph?searchtype=author&query=Alvarez-Crespo%2C+N">N. Alvarez-Crespo</a>, <a href="/search/astro-ph?searchtype=author&query=Batista%2C+R+A">R. Alves Batista</a>, <a href="/search/astro-ph?searchtype=author&query=Amans%2C+J+-">J. -P. Amans</a>, <a href="/search/astro-ph?searchtype=author&query=Amato%2C+E">E. Amato</a>, <a href="/search/astro-ph?searchtype=author&query=Ambrosi%2C+G">G. Ambrosi</a>, <a href="/search/astro-ph?searchtype=author&query=Angel%2C+L">L. Angel</a>, <a href="/search/astro-ph?searchtype=author&query=Aramo%2C+C">C. Aramo</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Arnesen%2C+T+T+H">T. T. H. Arnesen</a>, <a href="/search/astro-ph?searchtype=author&query=Arrabito%2C+L">L. Arrabito</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</a>, <a href="/search/astro-ph?searchtype=author&query=Ascasibar%2C+Y">Y. Ascasibar</a>, <a href="/search/astro-ph?searchtype=author&query=Aschersleben%2C+J">J. Aschersleben</a>, <a href="/search/astro-ph?searchtype=author&query=Ashkar%2C+H">H. Ashkar</a> , et al. (540 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="2403.04857v2-abstract-short" style="display: inline;"> Monochromatic gamma-ray signals constitute a potential smoking gun signature for annihilating or decaying dark matter particles that could relatively easily be distinguished from astrophysical or instrumental backgrounds. We provide an updated assessment of the sensitivity of the Cherenkov Telescope Array (CTA) to such signals, based on observations of the Galactic centre region as well as of sele… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.04857v2-abstract-full').style.display = 'inline'; document.getElementById('2403.04857v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.04857v2-abstract-full" style="display: none;"> Monochromatic gamma-ray signals constitute a potential smoking gun signature for annihilating or decaying dark matter particles that could relatively easily be distinguished from astrophysical or instrumental backgrounds. We provide an updated assessment of the sensitivity of the Cherenkov Telescope Array (CTA) to such signals, based on observations of the Galactic centre region as well as of selected dwarf spheroidal galaxies. We find that current limits and detection prospects for dark matter masses above 300 GeV will be significantly improved, by up to an order of magnitude in the multi-TeV range. This demonstrates that CTA will set a new standard for gamma-ray astronomy also in this respect, as the world's largest and most sensitive high-energy gamma-ray observatory, in particular due to its exquisite energy resolution at TeV energies and the adopted observational strategy focussing on regions with large dark matter densities. Throughout our analysis, we use up-to-date instrument response functions, and we thoroughly model the effect of instrumental systematic uncertainties in our statistical treatment. We further present results for other potential signatures with sharp spectral features, e.g.~box-shaped spectra, that would likewise very clearly point to a particle dark matter origin. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.04857v2-abstract-full').style.display = 'none'; document.getElementById('2403.04857v2-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">44 pages JCAP style (excluding author list and references), 19 figures; minor changes to match published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> JCAP 07 (2024) 047 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.02159">arXiv:2403.02159</a> <span> [<a href="https://arxiv.org/pdf/2403.02159">pdf</a>, <a href="https://arxiv.org/format/2403.02159">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/stae649">10.1093/mnras/stae649 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The variability patterns of the TeV blazar PG 1553+113 from a decade of MAGIC and multi-band observations </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=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhir%2C+J">J. Abhir</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Bernete%2C+J">J. Bernete</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</a> , et al. (242 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="2403.02159v1-abstract-short" style="display: inline;"> PG 1553+113 is one of the few blazars with a convincing quasi-periodic emission in the gamma-ray band. The source is also a very high-energy (VHE; >100 GeV) gamma-ray emitter. To better understand its properties and identify the underlying physical processes driving its variability, the MAGIC Collaboration initiated a multiyear, multiwavelength monitoring campaign in 2015 involving the OVRO 40-m a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02159v1-abstract-full').style.display = 'inline'; document.getElementById('2403.02159v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.02159v1-abstract-full" style="display: none;"> PG 1553+113 is one of the few blazars with a convincing quasi-periodic emission in the gamma-ray band. The source is also a very high-energy (VHE; >100 GeV) gamma-ray emitter. To better understand its properties and identify the underlying physical processes driving its variability, the MAGIC Collaboration initiated a multiyear, multiwavelength monitoring campaign in 2015 involving the OVRO 40-m and Medicina radio telescopes, REM, KVA, and the MAGIC telescopes, Swift and Fermi satellites, and the WEBT network. The analysis presented in this paper uses data until 2017 and focuses on the characterization of the variability. The gamma-ray data show a (hint of a) periodic signal compatible with literature, but the X-ray and VHE gamma-ray data do not show statistical evidence for a periodic signal. In other bands, the data are compatible with the gamma-ray period, but with a relatively high p-value. The complex connection between the low and high-energy emission and the non-monochromatic modulation and changes in flux suggests that a simple one-zone model is unable to explain all the variability. Instead, a model including a periodic component along with multiple emission zones is required. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02159v1-abstract-full').style.display = 'none'; document.getElementById('2403.02159v1-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">Accepted for publication in Monthly Notices of the Royal Astronomical Society. 19 pages, 9 figures. Corresponding authors: Elisa Prandini, Antonio Stamerra, Talvikki Hovatta</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.08560">arXiv:2401.08560</a> <span> [<a href="https://arxiv.org/pdf/2401.08560">pdf</a>, <a href="https://arxiv.org/format/2401.08560">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"> Insights into the broad-band emission of the TeV blazar Mrk 501 during the first X-ray polarization measurements </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhir%2C+J">J. Abhir</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">A. Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Bautista%2C+A">A. Bautista</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Bernete%2C+J">J. Bernete</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a> , et al. (239 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="2401.08560v1-abstract-short" style="display: inline;"> We present the first multi-wavelength study of Mrk 501 including very-high-energy (VHE) gamma-ray observations simultaneous to X-ray polarization measurements from the Imaging X-ray Polarimetry Explorer (IXPE). We use radio-to-VHE data from a multi-wavelength campaign organized between 2022-03-01 and 2022-07-19. The observations were performed by MAGIC, Fermi-LAT, NuSTAR, Swift (XRT and UVOT), and… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.08560v1-abstract-full').style.display = 'inline'; document.getElementById('2401.08560v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.08560v1-abstract-full" style="display: none;"> We present the first multi-wavelength study of Mrk 501 including very-high-energy (VHE) gamma-ray observations simultaneous to X-ray polarization measurements from the Imaging X-ray Polarimetry Explorer (IXPE). We use radio-to-VHE data from a multi-wavelength campaign organized between 2022-03-01 and 2022-07-19. The observations were performed by MAGIC, Fermi-LAT, NuSTAR, Swift (XRT and UVOT), and several instruments covering the optical and radio bands. During the IXPE pointings, the VHE state is close to the average behavior with a 0.2-1 TeV flux of 20%-50% the emission of the Crab Nebula. Despite the average VHE activity, an extreme X-ray behavior is measured for the first two IXPE pointings in March 2022 with a synchrotron peak frequency >1 keV. For the third IXPE pointing in July 2022, the synchrotron peak shifts towards lower energies and the optical/X-ray polarization degrees drop. The X-ray polarization is systematically higher than at lower energies, suggesting an energy-stratification of the jet. While during the IXPE epochs the polarization angle in the X-ray, optical and radio bands align well, we find a clear discrepancy in the optical and radio polarization angles in the middle of the campaign. We model the broad-band spectra simultaneous to the IXPE pointings assuming a compact zone dominating in the X-rays and VHE, and an extended zone stretching further downstream the jet dominating the emission at lower energies. NuSTAR data allow us to precisely constrain the synchrotron peak and therefore the underlying electron distribution. The change between the different states observed in the three IXPE pointings can be explained by a change of magnetization and/or emission region size, which directly connects the shift of the synchrotron peak to lower energies with the drop in polarization degree. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.08560v1-abstract-full').style.display = 'none'; document.getElementById('2401.08560v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">Accepted for publication in Astronomy & Astrophysics. 19 pages, 9 figures. Corresponding authors: Lea Heckmann, Axel Arbet Engels, David Paneque</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.07798">arXiv:2401.07798</a> <span> [<a href="https://arxiv.org/pdf/2401.07798">pdf</a>, <a href="https://arxiv.org/format/2401.07798">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/10.1016/j.dark.2024.101425">10.1016/j.dark.2024.101425 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Constraints on axion-like particles with the Perseus Galaxy Cluster 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=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhir%2C+J">J. Abhir</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernete%2C+J">J. Bernete</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a> , et al. (189 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="2401.07798v1-abstract-short" style="display: inline;"> Axion-like particles (ALPs) are pseudo-Nambu-Goldstone bosons that emerge in various theories beyond the standard model. These particles can interact with high-energy photons in external magnetic fields, influencing the observed gamma-ray spectrum. This study analyzes 41.3 hrs of observational data from the Perseus Galaxy Cluster collected with the MAGIC telescopes. We focused on the spectra the r… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.07798v1-abstract-full').style.display = 'inline'; document.getElementById('2401.07798v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.07798v1-abstract-full" style="display: none;"> Axion-like particles (ALPs) are pseudo-Nambu-Goldstone bosons that emerge in various theories beyond the standard model. These particles can interact with high-energy photons in external magnetic fields, influencing the observed gamma-ray spectrum. This study analyzes 41.3 hrs of observational data from the Perseus Galaxy Cluster collected with the MAGIC telescopes. We focused on the spectra the radio galaxy in the center of the cluster: NGC 1275. By modeling the magnetic field surrounding this target, we searched for spectral indications of ALP presence. Despite finding no statistical evidence of ALP signatures, we were able to exclude ALP models in the sub-micro electronvolt range. Our analysis improved upon previous work by calculating the full likelihood and statistical coverage for all considered models across the parameter space. Consequently, we achieved the most stringent limits to date for ALP masses around 50 neV, with cross sections down to $g_{a纬} = 3 \times 10^{-12}$ GeV$^{-1}$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.07798v1-abstract-full').style.display = 'none'; document.getElementById('2401.07798v1-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 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">25 pages, 10 figures, accepted for publication in Physics of the Dark Universe</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.04420">arXiv:2401.04420</a> <span> [<a href="https://arxiv.org/pdf/2401.04420">pdf</a>, <a href="https://arxiv.org/format/2401.04420">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/ad1ce4">10.3847/1538-4357/ad1ce4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Detection of X-ray Polarization from the Blazar 1ES 1959+650 with the Imaging X-ray Polarimetry Explorer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">Manel Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Negro%2C+M">Michela Negro</a>, <a href="/search/astro-ph?searchtype=author&query=Peirson%2C+A+L">Abel Lawrence Peirson</a>, <a href="/search/astro-ph?searchtype=author&query=Perri%2C+M">Matteo Perri</a>, <a href="/search/astro-ph?searchtype=author&query=Puccetti%2C+S">Simonetta Puccetti</a>, <a href="/search/astro-ph?searchtype=author&query=Rabinowitz%2C+P+L">Pazit L. Rabinowitz</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Savchenko%2C+S+S">Sergey S. Savchenko</a>, <a href="/search/astro-ph?searchtype=author&query=Blinov%2C+D">Dmitry Blinov</a>, <a href="/search/astro-ph?searchtype=author&query=Bourbah%2C+I+G">Ioakeim G. Bourbah</a>, <a href="/search/astro-ph?searchtype=author&query=Kiehlmann%2C+S">Sebastian Kiehlmann</a>, <a href="/search/astro-ph?searchtype=author&query=Kontopodis%2C+E">Evangelos Kontopodis</a>, <a href="/search/astro-ph?searchtype=author&query=Mandarakas%2C+N">Nikos Mandarakas</a>, <a href="/search/astro-ph?searchtype=author&query=Romanopoulos%2C+S">Stylianos Romanopoulos</a>, <a href="/search/astro-ph?searchtype=author&query=Skalidis%2C+R">Raphael Skalidis</a>, <a href="/search/astro-ph?searchtype=author&query=Vervelaki%2C+A">Anna Vervelaki</a>, <a href="/search/astro-ph?searchtype=author&query=Aceituno%2C+F+J">Francisco Jos茅 Aceituno</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M+I">Maria I. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Casanova%2C+V">V铆ctor Casanova</a> , et al. (121 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="2401.04420v1-abstract-short" style="display: inline;"> Observations of linear polarization in the 2-8 keV energy range with the Imaging X-ray Polarimetry Explorer (IXPE) explore the magnetic field geometry and dynamics of the regions generating non-thermal radiation in relativistic jets of blazars. These jets, particularly in blazars whose spectral energy distribution peaks at X-ray energies, emit X-rays via synchrotron radiation from high-energy part… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.04420v1-abstract-full').style.display = 'inline'; document.getElementById('2401.04420v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.04420v1-abstract-full" style="display: none;"> Observations of linear polarization in the 2-8 keV energy range with the Imaging X-ray Polarimetry Explorer (IXPE) explore the magnetic field geometry and dynamics of the regions generating non-thermal radiation in relativistic jets of blazars. These jets, particularly in blazars whose spectral energy distribution peaks at X-ray energies, emit X-rays via synchrotron radiation from high-energy particles within the jet. IXPE observations of the X-ray selected BL Lac-type blazar 1ES 1959+650 in 2022 May 3-4 showed a significant linear polarization degree of $螤_\mathrm{x} = 8.0\% \pm 2.3\%$ at an electric-vector position angle $蠄_\mathrm{x} = 123^\circ \pm 8^\circ$. However, in 2022 June 9-12, only an upper limit of $螤_\mathrm{x} \leq 5.1\%$ could be derived (at the 99% confidence level). The degree of optical polarization at that time $螤_\mathrm{O} \sim 5\%$ is comparable to the X-ray measurement. We investigate possible scenarios for these findings, including temporal and geometrical depolarization effects. Unlike some other X-ray selected BL Lac objects, there is no significant chromatic dependence of the measured polarization in 1ES 1959+650, and its low X-ray polarization may be attributed to turbulence in the jet flow with dynamical timescales shorter than 1 day. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.04420v1-abstract-full').style.display = 'none'; document.getElementById('2401.04420v1-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 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">16 pages, 4 figures, accepted for publication in The Astrophysical Journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, 963 (2024) 5 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.10732">arXiv:2312.10732</a> <span> [<a href="https://arxiv.org/pdf/2312.10732">pdf</a>, <a href="https://arxiv.org/format/2312.10732">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"> First characterization of the emission behavior of Mrk421 from radio to VHE gamma rays with simultaneous X-ray polarization measurements </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abhir%2C+J">J. Abhir</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernete%2C+J">J. Bernete</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</a>, <a href="/search/astro-ph?searchtype=author&query=Biland%2C+A">A. Biland</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="2312.10732v1-abstract-short" style="display: inline;"> We perform the first broadband study of Mrk421 from radio to TeV gamma rays with simultaneous measurements of the X-ray polarization from IXPE. The data were collected within an extensive multiwavelength campaign organized between May and June 2022 using MAGIC, Fermi-LAT, NuSTAR, XMM-Newton, Swift, and several optical and radio telescopes to complement IXPE. During the IXPE exposures, the measured… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.10732v1-abstract-full').style.display = 'inline'; document.getElementById('2312.10732v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.10732v1-abstract-full" style="display: none;"> We perform the first broadband study of Mrk421 from radio to TeV gamma rays with simultaneous measurements of the X-ray polarization from IXPE. The data were collected within an extensive multiwavelength campaign organized between May and June 2022 using MAGIC, Fermi-LAT, NuSTAR, XMM-Newton, Swift, and several optical and radio telescopes to complement IXPE. During the IXPE exposures, the measured 0.2-1 TeV flux is close to the quiescent state and ranges from 25% to 50% of the Crab Nebula without intra-night variability. Throughout the campaign, the VHE and X-ray emission are positively correlated at a $4蟽$ significance level. The IXPE measurements unveil a X-ray polarization degree that is a factor of 2-5 higher than in the optical/radio bands; that implies an energy-stratified jet in which the VHE photons are emitted co-spatially with the X-rays, in the vicinity of a shock front. The June 2022 observations exhibit a rotation of the X-ray polarization angle. Despite no simultaneous VHE coverage being available during a large fraction of the swing, the Swift-XRT monitoring unveils an X-ray flux increase with a clear spectral hardening. It suggests that flares in high synchrotron peaked blazars can be accompanied by a polarization angle rotation, as observed in some flat spectrum radio quasars. Finally, during the polarization angle rotation, NuSTAR data reveal two contiguous spectral hysteresis loops in opposite directions (clockwise and counter-clockwise), implying important changes in the particle acceleration efficiency on $\sim$hour timescales. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.10732v1-abstract-full').style.display = 'none'; document.getElementById('2312.10732v1-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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 Astronomy & Astrophysics. 29 pages, 22 figures. Corresponding authors: Axel Arbet Engels, Felix Schmuckermaier, David Paneque</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.01157">arXiv:2311.01157</a> <span> [<a href="https://arxiv.org/pdf/2311.01157">pdf</a>, <a href="https://arxiv.org/format/2311.01157">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202346885">10.1051/0004-6361/202346885 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Repeating Flaring Activity of Blazar AO 0235+164 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pedrosa%2C+J+E">Juan Escudero Pedrosa</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Tramacere%2C+A">Andrea Tramacere</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S">Svetlana Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Weaver%2C+Z+R">Z. R. Weaver</a>, <a href="/search/astro-ph?searchtype=author&query=Casadio%2C+C">Carolina Casadio</a>, <a href="/search/astro-ph?searchtype=author&query=Thum%2C+C">Clemens Thum</a>, <a href="/search/astro-ph?searchtype=author&query=Myserlis%2C+I">Ioannis Myserlis</a>, <a href="/search/astro-ph?searchtype=author&query=Fuentes%2C+A">Antonio Fuentes</a>, <a href="/search/astro-ph?searchtype=author&query=Traianou%2C+E">Efthalia Traianou</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+J">Jae-Young Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+J">Joana Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=L%C3%B3pez-Coto%2C+R">Rub茅n L贸pez-Coto</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=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Blinov%2C+D+A">Dmitriy A. Blinov</a>, <a href="/search/astro-ph?searchtype=author&query=Borman%2C+G+A">G. A. Borman</a>, <a href="/search/astro-ph?searchtype=author&query=Grishina%2C+T+S">T. S. Grishina</a>, <a href="/search/astro-ph?searchtype=author&query=Hagen-Thorn%2C+V+A">V. A. Hagen-Thorn</a>, <a href="/search/astro-ph?searchtype=author&query=Kopatskaya%2C+E+N">E. N. Kopatskaya</a>, <a href="/search/astro-ph?searchtype=author&query=Larionova%2C+E+G">E. G. Larionova</a>, <a href="/search/astro-ph?searchtype=author&query=Larionov%2C+V+M">V. M. Larionov</a>, <a href="/search/astro-ph?searchtype=author&query=Larionova%2C+L+V">L. V. Larionova</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="2311.01157v1-abstract-short" style="display: inline;"> Context. Blazar AO 0235+164, located at redshift z = 0.94, has undergone several sharp multi-spectral-range flaring episodes during the last decades. In particular, the episodes peaking in 2008 and 2015, that received extensive multi-wavelength coverage, exhibited interesting behavior. Aims. We study the actual origin of these two observed flares by constraining the properties of the observed ph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.01157v1-abstract-full').style.display = 'inline'; document.getElementById('2311.01157v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.01157v1-abstract-full" style="display: none;"> Context. Blazar AO 0235+164, located at redshift z = 0.94, has undergone several sharp multi-spectral-range flaring episodes during the last decades. In particular, the episodes peaking in 2008 and 2015, that received extensive multi-wavelength coverage, exhibited interesting behavior. Aims. We study the actual origin of these two observed flares by constraining the properties of the observed photo-polarimetric variability, those of the broad-band spectral energy-distribution and the observed time-evolution behavior of the source as seen by ultra-high resolution total-flux and polarimetric Very-long-baseline interferometry (VLBI) imaging. Methods. The analysis of VLBI images allows us to constrain kinematic and geometrical parameters of the 7 mm jet. We use the Discrete Correlation Function to compute the statistical correlation and the delays between emission at different spectral ranges. Multi-epoch modeling of the spectral energy distributions allows us to propose specific models of emission; in particular for the unusual spectral features observed in this source in the X-ray region of the spectrum during strong multi spectral-range flares. Results. We find that these X-ray spectral features can be explained by an emission component originating in a separate particle distribution than the one responsible for the two standard blazar bumps. This is in agreement with the results of our correlation analysis that do not find a strong correlation between the X-rays and the remaining spectral ranges. We find that both external Compton dominated and synchrotron self-Compton dominated models can explain the observed spectral energy distributions. However, synchrotron self-Compton models are strongly favored by the delays and geometrical parameters inferred from the observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.01157v1-abstract-full').style.display = 'none'; document.getElementById('2311.01157v1-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 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.11510">arXiv:2310.11510</a> <span> [<a href="https://arxiv.org/pdf/2310.11510">pdf</a>, <a href="https://arxiv.org/format/2310.11510">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"> Observations of Low and Intermediate Spectral Peak Blazars with the Imaging X-ray Polarimetry Explorer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Lalla%2C+N">Niccolo Di Lalla</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+E">Dawoon E. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Negro%2C+M">Michela Negro</a>, <a href="/search/astro-ph?searchtype=author&query=Omodei%2C+N">Nicola Omodei</a>, <a href="/search/astro-ph?searchtype=author&query=Peirson%2C+A+L">Abel L. Peirson</a>, <a href="/search/astro-ph?searchtype=author&query=Perri%2C+M">Matteo Perri</a>, <a href="/search/astro-ph?searchtype=author&query=Puccetti%2C+S">Simonetta Puccetti</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Ivan Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Berdyugin%2C+A+V">Andrei V. Berdyugin</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">Elisabetta Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cavero%2C+N+R">Nicole Rodriguez Cavero</a>, <a href="/search/astro-ph?searchtype=author&query=Donnarumma%2C+I">Immacolata Donnarumma</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Jormanainen%2C+J">Jenni Jormanainen</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">Henric Krawczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Lindfors%2C+E">Elina Lindfors</a>, <a href="/search/astro-ph?searchtype=author&query=Marin%2C+F">Frederic Marin</a>, <a href="/search/astro-ph?searchtype=author&query=Massaro%2C+F">Francesco Massaro</a>, <a href="/search/astro-ph?searchtype=author&query=Pacciani%2C+L">Luigi Pacciani</a> , et al. (133 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="2310.11510v2-abstract-short" style="display: inline;"> We present X-ray polarimetry observations from the Imaging X-ray Polarimetry Explorer (IXPE) of three low spectral peak and one intermediate spectral peak blazars, namely 3C 273, 3C 279, 3C 454.3, and S5 0716+714. For none of these objects was IXPE able to detect X-ray polarization at the 3$蟽$ level. However, we placed upper limits on the polarization degree at $\sim$10-30\%. The undetected polari… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.11510v2-abstract-full').style.display = 'inline'; document.getElementById('2310.11510v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.11510v2-abstract-full" style="display: none;"> We present X-ray polarimetry observations from the Imaging X-ray Polarimetry Explorer (IXPE) of three low spectral peak and one intermediate spectral peak blazars, namely 3C 273, 3C 279, 3C 454.3, and S5 0716+714. For none of these objects was IXPE able to detect X-ray polarization at the 3$蟽$ level. However, we placed upper limits on the polarization degree at $\sim$10-30\%. The undetected polarizations favor models where the X-ray band is dominated by unpolarized photons upscattered by relativistic electrons in the jets of blazars, although hadronic models are not completely eliminated. We discuss the X-ray polarization upper limits in the context of our contemporaneous multiwavelength polarization campaigns. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.11510v2-abstract-full').style.display = 'none'; document.getElementById('2310.11510v2-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> 19 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">19 pages, 10 figures, 6 tables; submitted to 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/2310.07413">arXiv:2310.07413</a> <span> [<a href="https://arxiv.org/pdf/2310.07413">pdf</a>, <a href="https://arxiv.org/format/2310.07413">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"> Chasing Gravitational Waves with the Cherenkov Telescope Array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Green%2C+J+G">Jarred Gershon Green</a>, <a href="/search/astro-ph?searchtype=author&query=Carosi%2C+A">Alessandro Carosi</a>, <a href="/search/astro-ph?searchtype=author&query=Nava%2C+L">Lara Nava</a>, <a href="/search/astro-ph?searchtype=author&query=Patricelli%2C+B">Barbara Patricelli</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BCssler%2C+F">Fabian Sch眉ssler</a>, <a href="/search/astro-ph?searchtype=author&query=Seglar-Arroyo%2C+M">Monica Seglar-Arroyo</a>, <a href="/search/astro-ph?searchtype=author&query=Consortium%2C+C">Cta Consortium</a>, <a href="/search/astro-ph?searchtype=author&query=%3A"> :</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+K">Kazuki Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">Shotaro Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Acharyya%2C+A">Atreya Acharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Adam%2C+R">Remi Adam</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">Arnau Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Ivan Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Alfaro%2C+J">Jorge Alfaro</a>, <a href="/search/astro-ph?searchtype=author&query=Alvarez-Crespo%2C+N">Nuria Alvarez-Crespo</a>, <a href="/search/astro-ph?searchtype=author&query=Batista%2C+R+A">Rafael Alves Batista</a>, <a href="/search/astro-ph?searchtype=author&query=Amans%2C+J">Jean-Philippe Amans</a>, <a href="/search/astro-ph?searchtype=author&query=Amato%2C+E">Elena Amato</a>, <a href="/search/astro-ph?searchtype=author&query=Ambrosino%2C+F">Filippo Ambrosino</a>, <a href="/search/astro-ph?searchtype=author&query=Ang%C3%BCner%2C+E+O">Ekrem Oguzhan Ang眉ner</a>, <a href="/search/astro-ph?searchtype=author&query=Antonelli%2C+L+A">Lucio Angelo Antonelli</a>, <a href="/search/astro-ph?searchtype=author&query=Aramo%2C+C">Carla Aramo</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">Cornelia Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Arrabito%2C+L">Luisa Arrabito</a> , et al. (545 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="2310.07413v3-abstract-short" style="display: inline;"> The detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.07413v3-abstract-full').style.display = 'inline'; document.getElementById('2310.07413v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.07413v3-abstract-full" style="display: none;"> The detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a gravitational wave signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. New observing modes and follow-up strategies are being developed for CTA to rapidly cover localization areas of gravitational wave events that are typically larger than the CTA field of view. This work will evaluate and provide estimations on the expected number of of gravitational wave events that will be observable with CTA, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.07413v3-abstract-full').style.display = 'none'; document.getElementById('2310.07413v3-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CTA-ICRC/2023/30 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.06473">arXiv:2310.06473</a> <span> [<a href="https://arxiv.org/pdf/2310.06473">pdf</a>, <a href="https://arxiv.org/format/2310.06473">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/stad2958">10.1093/mnras/stad2958 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> MAGIC detection of GRB 201216C at $z=1.1$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernete%2C+J">J. Bernete</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</a> , et al. (195 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="2310.06473v1-abstract-short" style="display: inline;"> Gamma-ray bursts (GRBs) are explosive transient events occurring at cosmological distances, releasing a large amount of energy as electromagnetic radiation over several energy bands. We report the detection of the long GRB~201216C by the MAGIC telescopes. The source is located at $z=1.1$ and thus it is the farthest one detected at very high energies. The emission above \SI{70}{\GeV} of GRB~201216C… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.06473v1-abstract-full').style.display = 'inline'; document.getElementById('2310.06473v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.06473v1-abstract-full" style="display: none;"> Gamma-ray bursts (GRBs) are explosive transient events occurring at cosmological distances, releasing a large amount of energy as electromagnetic radiation over several energy bands. We report the detection of the long GRB~201216C by the MAGIC telescopes. The source is located at $z=1.1$ and thus it is the farthest one detected at very high energies. The emission above \SI{70}{\GeV} of GRB~201216C is modelled together with multi-wavelength data within a synchrotron and synchrotron-self Compton (SSC) scenario. We find that SSC can explain the broadband data well from the optical to the very-high-energy band. For the late-time radio data, a different component is needed to account for the observed emission. Differently from previous GRBs detected in the very-high-energy range, the model for GRB~201216C strongly favors a wind-like medium. The model parameters have values similar to those found in past studies of the afterglows of GRBs detected up to GeV energies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.06473v1-abstract-full').style.display = 'none'; document.getElementById('2310.06473v1-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">13 pages, 6 figures, 2 tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Monthly Notices of the Royal Astronomical Society, Volume 527, Issue 3, January 2024, Pages 5856-5867 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.06097">arXiv:2310.06097</a> <span> [<a href="https://arxiv.org/pdf/2310.06097">pdf</a>, <a href="https://arxiv.org/format/2310.06097">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202347408">10.1051/0004-6361/202347408 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic Field Properties inside the Jet of Mrk 421: Multiwavelength Polarimetry Including the Imaging X-ray Polarimetry Explorer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+E">Dawoon E. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Midde%2C+R">Riccardo Midde</a>, <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Pacciani%2C+L">Luigi Pacciani</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">Fabrizio Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Cibrario%2C+N">Nicol貌 Cibrario</a>, <a href="/search/astro-ph?searchtype=author&query=Tugliani%2C+S">Stefano Tugliani</a>, <a href="/search/astro-ph?searchtype=author&query=Bonino%2C+R">Raffaella Bonino</a>, <a href="/search/astro-ph?searchtype=author&query=Negro%2C+M">Michela Negro</a>, <a href="/search/astro-ph?searchtype=author&query=Puccetti%2C+S">Simonetta Puccetti</a>, <a href="/search/astro-ph?searchtype=author&query=Tombesi%2C+F">Francesco Tombesi</a>, <a href="/search/astro-ph?searchtype=author&query=Costa%2C+E">Enrico Costa</a>, <a href="/search/astro-ph?searchtype=author&query=Donnarumma%2C+I">Immacolata Donnarumma</a>, <a href="/search/astro-ph?searchtype=author&query=Soffitta%2C+P">Paolo Soffitta</a>, <a href="/search/astro-ph?searchtype=author&query=Mizuno%2C+T">Tsunefumi Mizuno</a>, <a href="/search/astro-ph?searchtype=author&query=Fukazawa%2C+Y">Yasushi Fukazawa</a>, <a href="/search/astro-ph?searchtype=author&query=Kawabata%2C+K+S">Koji S. Kawabata</a>, <a href="/search/astro-ph?searchtype=author&query=Nakaoka%2C+T">Tatsuya Nakaoka</a>, <a href="/search/astro-ph?searchtype=author&query=Uemura%2C+M">Makoto Uemura</a>, <a href="/search/astro-ph?searchtype=author&query=Imazawa%2C+R">Ryo Imazawa</a> , et al. (111 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="2310.06097v1-abstract-short" style="display: inline;"> We conducted a polarimetry campaign from radio to X-ray wavelengths of the high-synchrotron-peak (HSP) blazar Mrk 421, including Imaging X-ray Polarimetry Explorer (IXPE) measurements on 2022 December 6-8. We detected X-ray polarization of Mrk 421 with a degree of $螤_{\rm X}$=14$\pm$1$\%$ and an electric-vector position angle $蠄_{\rm X}$=107$\pm$3$^{\circ}$ in the 2-8 keV band. From the time varia… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.06097v1-abstract-full').style.display = 'inline'; document.getElementById('2310.06097v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.06097v1-abstract-full" style="display: none;"> We conducted a polarimetry campaign from radio to X-ray wavelengths of the high-synchrotron-peak (HSP) blazar Mrk 421, including Imaging X-ray Polarimetry Explorer (IXPE) measurements on 2022 December 6-8. We detected X-ray polarization of Mrk 421 with a degree of $螤_{\rm X}$=14$\pm$1$\%$ and an electric-vector position angle $蠄_{\rm X}$=107$\pm$3$^{\circ}$ in the 2-8 keV band. From the time variability analysis, we find a significant episodic variation in $蠄_{\rm X}$. During 7 months from the first IXPE pointing of Mrk 421 in 2022 May, $蠄_{\rm X}$ varied across the range of 0$^{\circ}$ to 180$^{\circ}$, while $螤_{\rm X}$ maintained similar values within $\sim$10-15$\%$. Furthermore, a swing in $蠄_{\rm X}$ in 2022 June was accompanied by simultaneous spectral variations. The results of the multiwavelength polarimetry show that the X-ray polarization degree was generally $\sim$2-3 times greater than that at longer wavelengths, while the polarization angle fluctuated. Additionally, based on radio, infrared, and optical polarimetry, we find that rotation of $蠄$ occurred in the opposite direction with respect to the rotation of $蠄_{\rm X}$ over longer timescales at similar epochs. The polarization behavior observed across multiple wavelengths is consistent with previous IXPE findings for HSP blazars. This result favors the energy-stratified shock model developed to explain variable emission in relativistic jets. The accompanying spectral variation during the $蠄_{\rm X}$ rotation can be explained by a fluctuation in the physical conditions, e.g., in the energy distribution of relativistic electrons. The opposite rotation direction of $蠄$ between the X-ray and longer-wavelength polarization accentuates the conclusion that the X-ray emitting region is spatially separated from that at longer wavelengths. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.06097v1-abstract-full').style.display = 'none'; document.getElementById('2310.06097v1-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">17 pages, 13 figures, 4 tables; 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 681, A12 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.03922">arXiv:2310.03922</a> <span> [<a href="https://arxiv.org/pdf/2310.03922">pdf</a>, <a href="https://arxiv.org/format/2310.03922">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202347845">10.1051/0004-6361/202347845 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-year characterisation of the broad-band emission from the intermittent extreme BL Lac 1ES~2344+514 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Bernete%2C+J">J. Bernete</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</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> , et al. (210 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="2310.03922v1-abstract-short" style="display: inline;"> The BL Lac 1ES 2344+514 is known for temporary extreme properties (e.g., a shift of the synchrotron SED peak energy $谓_{synch,p}$ above 1keV). While those extreme states were so far observed only during high flux levels, additional multi-year observing campaigns are required to achieve a coherent picture. Here, we report the longest investigation of the source from radio to VHE performed so far, f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.03922v1-abstract-full').style.display = 'inline'; document.getElementById('2310.03922v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.03922v1-abstract-full" style="display: none;"> The BL Lac 1ES 2344+514 is known for temporary extreme properties (e.g., a shift of the synchrotron SED peak energy $谓_{synch,p}$ above 1keV). While those extreme states were so far observed only during high flux levels, additional multi-year observing campaigns are required to achieve a coherent picture. Here, we report the longest investigation of the source from radio to VHE performed so far, focusing on a systematic characterisation of the intermittent extreme states. While our results confirm that 1ES 2344+514 typically exhibits $谓_{synch,p}>$1keV during elevated flux periods, we also find periods where the extreme state coincides with low flux activity. A strong spectral variability thus happens in the quiescent state, and is likely caused by an increase of the electron acceleration efficiency without a change in the electron injection luminosity. We also report a strong X-ray flare (among the brightest for 1ES 2344+514) without a significant shift of $谓_{synch,p}$. During this particular flare, the X-ray spectrum is among the softest of the campaign. It unveils complexity in the spectral evolution, where the common harder-when-brighter trend observed in BL Lacs is violated. During a low and hard X-ray state, we find an excess of the UV flux with respect to an extrapolation of the X-ray spectrum to lower energies. This UV excess implies that at least two regions contribute significantly to the infrared/optical/ultraviolet/X-ray emission. Using the simultaneous MAGIC, XMM-Newton, NuSTAR, and AstroSat observations, we argue that a region possibly associated with the 10 GHz radio core may explain such an excess. Finally, we investigate a VHE flare, showing an absence of simultaneous variability in the 0.3-2keV band. Using a time-dependent leptonic modelling, we show that this behaviour, in contradiction to single-zone scenarios, can instead be explained by a two-component model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.03922v1-abstract-full').style.display = 'none'; document.getElementById('2310.03922v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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 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 682, A114 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.01954">arXiv:2310.01954</a> <span> [<a href="https://arxiv.org/pdf/2310.01954">pdf</a>, <a href="https://arxiv.org/format/2310.01954">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/10.1051/0004-6361/202346927">10.1051/0004-6361/202346927 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Performance of the joint LST-1 and MAGIC observations evaluated with Crab Nebula data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+K">K. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">A. Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Crespo%2C+N+A">N. Alvarez Crespo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Aramo%2C+C">C. Aramo</a>, <a href="/search/astro-ph?searchtype=author&query=Arbet-Engels%2C+A">A. Arbet-Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</a>, <a href="/search/astro-ph?searchtype=author&query=Aubert%2C+P">P. Aubert</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=Baktash%2C+A">A. Baktash</a>, <a href="/search/astro-ph?searchtype=author&query=Bamba%2C+A">A. Bamba</a>, <a href="/search/astro-ph?searchtype=author&query=Larriva%2C+A+B">A. Baquero Larriva</a>, <a href="/search/astro-ph?searchtype=author&query=Baroncelli%2C+L">L. Baroncelli</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a> , et al. (344 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="2310.01954v1-abstract-short" style="display: inline;"> Aims. LST-1, the prototype of the Large-Sized Telescope for the upcoming Cherenkov Telescope Array Observatory, is concluding its commissioning in Observatorio del Roque de los Muchachos on the island of La Palma. The proximity of LST-1 (Large-Sized Telescope 1) to the two MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescopes permits observations of the same gamma-ray events with both syste… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.01954v1-abstract-full').style.display = 'inline'; document.getElementById('2310.01954v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.01954v1-abstract-full" style="display: none;"> Aims. LST-1, the prototype of the Large-Sized Telescope for the upcoming Cherenkov Telescope Array Observatory, is concluding its commissioning in Observatorio del Roque de los Muchachos on the island of La Palma. The proximity of LST-1 (Large-Sized Telescope 1) to the two MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescopes permits observations of the same gamma-ray events with both systems. Methods. We describe the joint LST-1+MAGIC analysis pipeline and use simultaneous Crab Nebula observations and Monte Carlo simulations to assess the performance of the three-telescope system. The addition of the LST-1 telescope allows the recovery of events in which one of the MAGIC images is too dim to survive analysis quality cuts. Results. Thanks to the resulting increase in the collection area and stronger background rejection, we find a significant improvement in sensitivity, allowing the detection of 30% weaker fluxes in the energy range between 200 GeV and 3 TeV. The spectrum of the Crab Nebula, reconstructed in the energy range ~60 GeV to ~10 TeV, is in agreement with previous measurements. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.01954v1-abstract-full').style.display = 'none'; document.getElementById('2310.01954v1-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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 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 680, A66 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.01635">arXiv:2310.01635</a> <span> [<a href="https://arxiv.org/pdf/2310.01635">pdf</a>, <a href="https://arxiv.org/format/2310.01635">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"> X-ray Polarization of the BL Lac Type Blazar 1ES 0229+200 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ehlert%2C+S+R">Steven R. Ehlert</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">Fabrizio Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Kouch%2C+P+M">Pouya M. Kouch</a>, <a href="/search/astro-ph?searchtype=author&query=Lindfors%2C+E">Elina Lindfors</a>, <a href="/search/astro-ph?searchtype=author&query=Nilsson%2C+K">Kari Nilsson</a>, <a href="/search/astro-ph?searchtype=author&query=Myserlis%2C+I">Ioannis Myserlis</a>, <a href="/search/astro-ph?searchtype=author&query=Gurwell%2C+M">Mark Gurwell</a>, <a href="/search/astro-ph?searchtype=author&query=Rao%2C+R">Ramprasad Rao</a>, <a href="/search/astro-ph?searchtype=author&query=Aceituno%2C+F+J">Francisco Jose Aceituno</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Casanova%2C+V">Victor Casanova</a>, <a href="/search/astro-ph?searchtype=author&query=Agiz-Gonzalez%2C+B">Beatriz Agiz-Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Escudero%2C+J">Juan Escudero</a>, <a href="/search/astro-ph?searchtype=author&query=Santos%2C+J+O">Jorge Otero Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Sota%2C+A">Alfredo Sota</a>, <a href="/search/astro-ph?searchtype=author&query=Angelakis%2C+E">Emmanouil Angelakis</a>, <a href="/search/astro-ph?searchtype=author&query=Kraus%2C+A">Alexander Kraus</a>, <a href="/search/astro-ph?searchtype=author&query=Keating%2C+G+K">Garrett K. Keating</a>, <a href="/search/astro-ph?searchtype=author&query=Antonelli%2C+L+A">Lucio A. Antonelli</a>, <a href="/search/astro-ph?searchtype=author&query=Bachetti%2C+M">Matteo Bachetti</a>, <a href="/search/astro-ph?searchtype=author&query=Baldini%2C+L">Luca Baldini</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="2310.01635v1-abstract-short" style="display: inline;"> We present polarization measurements in the $2-8 \thinspace \mathrm{keV}$ band from blazar 1ES 0229+200, the first extreme high synchrotron peaked source to be observed by the Imaging X-ray Polarimetry Explorer (IXPE). Combining two exposures separated by about two weeks, we find the degree of polarization to be $螤_{X} = 17.9 \pm 2.8 \%$ at an electric-vector position angle… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.01635v1-abstract-full').style.display = 'inline'; document.getElementById('2310.01635v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.01635v1-abstract-full" style="display: none;"> We present polarization measurements in the $2-8 \thinspace \mathrm{keV}$ band from blazar 1ES 0229+200, the first extreme high synchrotron peaked source to be observed by the Imaging X-ray Polarimetry Explorer (IXPE). Combining two exposures separated by about two weeks, we find the degree of polarization to be $螤_{X} = 17.9 \pm 2.8 \%$ at an electric-vector position angle $蠄_X = 25.0 \pm 4.6^{\circ}$ using a spectropolarimetric fit from joint IXPE and XMM-Newton observations. There is no evidence for the polarization degree or angle varying significantly with energy or time on both short time scales (hours) or longer time scales (days). The contemporaneous polarization degree at optical wavelengths was $>$7$\times$ lower, making 1ES 0229+200 the most strongly chromatic blazar yet observed. This high X-ray polarization compared to the optical provides further support that X-ray emission in high-peaked blazars originates in shock-accelerated, energy-stratified electron populations, but is in tension with many recent modeling efforts attempting to reproduce the spectral energy distribution of 1ES 0229+200 which attribute the extremely high energy synchrotron and Compton peaks to Fermi acceleration in the vicinity of strongly turbulent magnetic fields. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.01635v1-abstract-full').style.display = 'none'; document.getElementById('2310.01635v1-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">17 Pages, 6 Figures, Resubmitted to ApJ after addressing referee comments</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.10803">arXiv:2308.10803</a> <span> [<a href="https://arxiv.org/pdf/2308.10803">pdf</a>, <a href="https://arxiv.org/format/2308.10803">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/10.22323/1.444.1512">10.22323/1.444.1512 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The UHECR-FR0 Radio Galaxy Connection: A Multi-Messenger Study of Energy Spectra/Composition Emission and Intergalactic Magnetic Field Propagation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lundquist%2C+J+P">J. P. Lundquist</a>, <a href="/search/astro-ph?searchtype=author&query=Merten%2C+L">L. Merten</a>, <a href="/search/astro-ph?searchtype=author&query=Vorobiov%2C+S">S. Vorobiov</a>, <a href="/search/astro-ph?searchtype=author&query=Boughelilba%2C+M">M. Boughelilba</a>, <a href="/search/astro-ph?searchtype=author&query=Reimer%2C+A">A. Reimer</a>, <a href="/search/astro-ph?searchtype=author&query=Da+Vela%2C+P">P. Da Vela</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">F. Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">G. Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Righi%2C+C">C. Righi</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="2308.10803v1-abstract-short" style="display: inline;"> This study investigates low luminosity Fanaroff-Riley Type 0 (FR0) radio galaxies as a potentially significant source of ultra-high energy cosmic rays (UHECRs). Due to their much higher prevalence in the local universe compared to more powerful radio galaxies (about five times more than FR-1s), FR0s may provide a substantial fraction of the total UHECR energy density. To determine the nucleon comp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10803v1-abstract-full').style.display = 'inline'; document.getElementById('2308.10803v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.10803v1-abstract-full" style="display: none;"> This study investigates low luminosity Fanaroff-Riley Type 0 (FR0) radio galaxies as a potentially significant source of ultra-high energy cosmic rays (UHECRs). Due to their much higher prevalence in the local universe compared to more powerful radio galaxies (about five times more than FR-1s), FR0s may provide a substantial fraction of the total UHECR energy density. To determine the nucleon composition and energy spectrum of UHECRs emitted by FR0 sources, simulation results from CRPropa3 are fit to Pierre Auger Observatory data. The resulting emission spectral indices, rigidity cutoffs, and nucleon fractions are compared to recent Auger results. The FR0 simulations include the approximately isotropic distribution of FR0 galaxies and various intergalactic magnetic field configurations (including random and structured fields) and predict the fluxes of secondary photons and neutrinos produced during UHECR propagation through cosmic photon backgrounds. This comprehensive simulation allows for investigating the properties of the FR0 sources using observational multi-messenger data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10803v1-abstract-full').style.display = 'none'; document.getElementById('2308.10803v1-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 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">PoS 444 (38th ICRC) 1512</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.00039">arXiv:2308.00039</a> <span> [<a href="https://arxiv.org/pdf/2308.00039">pdf</a>, <a href="https://arxiv.org/format/2308.00039">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"> IXPE and multi-wavelength observations of blazar PG 1553+113 reveal an orphan optical polarization swing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Perri%2C+M">Matteo Perri</a>, <a href="/search/astro-ph?searchtype=author&query=Puccetti%2C+S">Simonetta Puccetti</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Cavero%2C+N+R">Nicole Rodriguez Cavero</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">Fabrizio Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Donnarumma%2C+I">Immacolata Donnarumma</a>, <a href="/search/astro-ph?searchtype=author&query=Laurenti%2C+M">Marco Laurenti</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Pacciani%2C+L">Luigi Pacciani</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+E">Dawoon E. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Aceituno%2C+F+J">Francisco Jos茅 Aceituno</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Casanova%2C+V">V铆ctor Casanova</a>, <a href="/search/astro-ph?searchtype=author&query=Ag%C3%ADs-Gonz%C3%A1lez%2C+B">Beatriz Ag铆s-Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Sota%2C+A">Alfredo Sota</a>, <a href="/search/astro-ph?searchtype=author&query=Casadio%2C+C">Carolina Casadio</a>, <a href="/search/astro-ph?searchtype=author&query=Escudero%2C+J">Juan Escudero</a>, <a href="/search/astro-ph?searchtype=author&query=Myserlis%2C+I">Ioannis Myserlis</a>, <a href="/search/astro-ph?searchtype=author&query=Sievers%2C+A">Albrecht Sievers</a>, <a href="/search/astro-ph?searchtype=author&query=Kouch%2C+P+M">Pouya M. Kouch</a> , et al. (97 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="2308.00039v1-abstract-short" style="display: inline;"> The lower energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consensus regarding jet emission processes, the particle acceleration mechanism is still debated. Here, we present the first X-ray polarization observations of PG 1553+113, a high-synchrotron-peak blazar observed by the Imagin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.00039v1-abstract-full').style.display = 'inline'; document.getElementById('2308.00039v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.00039v1-abstract-full" style="display: none;"> The lower energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consensus regarding jet emission processes, the particle acceleration mechanism is still debated. Here, we present the first X-ray polarization observations of PG 1553+113, a high-synchrotron-peak blazar observed by the Imaging X-ray Polarimetry Explorer (IXPE). We detect an X-ray polarization degree of $(10\pm2)\%$ along an electric-vector position angle of $蠄_X=86^{\circ}\pm8^{\circ}$. At the same time, the radio and optical polarization degrees are lower by a factor of $\sim$3. During our IXPE pointing, we observed the first orphan optical polarization swing of the IXPE era, as the optical angle of PG 1553+113 underwent a smooth monotonic rotation by about 125$^\circ$, with a rate of $\sim$17 degrees per day. We do not find evidence of a similar rotation in either radio or X-rays, which suggests that the X-ray and optically emitting regions are separate or, at most, partially co-spatial. Our spectro-polarimetric results provide further evidence that the steady-state X-ray emission in blazars originates in a shock-accelerated and energy-stratified electron population. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.00039v1-abstract-full').style.display = 'none'; document.getElementById('2308.00039v1-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 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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 pubblication in The Astrophysical Journal Letters. 3 Figures, 13 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.12960">arXiv:2306.12960</a> <span> [<a href="https://arxiv.org/pdf/2306.12960">pdf</a>, <a href="https://arxiv.org/ps/2306.12960">ps</a>, <a href="https://arxiv.org/format/2306.12960">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> <p class="title is-5 mathjax"> Observations of the Crab Nebula and Pulsar with the Large-Sized Telescope Prototype of the Cherenkov Telescope Array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Project%2C+C">CTA-LST Project</a>, <a href="/search/astro-ph?searchtype=author&query=%3A"> :</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+K">K. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Aguasca-Cabot%2C+A">A. Aguasca-Cabot</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Crespo%2C+N+A">N. Alvarez Crespo</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=Aramo%2C+C">C. Aramo</a>, <a href="/search/astro-ph?searchtype=author&query=Arbet-Engels%2C+A">A. Arbet-Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</a>, <a href="/search/astro-ph?searchtype=author&query=Aubert%2C+P">P. Aubert</a>, <a href="/search/astro-ph?searchtype=author&query=Baktash%2C+A">A. Baktash</a>, <a href="/search/astro-ph?searchtype=author&query=Bamba%2C+A">A. Bamba</a>, <a href="/search/astro-ph?searchtype=author&query=Larriva%2C+A+B">A. Baquero Larriva</a>, <a href="/search/astro-ph?searchtype=author&query=Baroncelli%2C+L">L. Baroncelli</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=Batkovic%2C+I">I. Batkovic</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernardini%2C+E">E. Bernardini</a> , et al. (467 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="2306.12960v3-abstract-short" style="display: inline;"> CTA (Cherenkov Telescope Array) is the next generation ground-based observatory for gamma-ray astronomy at very-high energies. The Large-Sized Telescope prototype (LST-1) is located at the Northern site of CTA, on the Canary Island of La Palma. LSTs are designed to provide optimal performance in the lowest part of the energy range covered by CTA, down to $\simeq 20$ GeV. LST-1 started performing a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.12960v3-abstract-full').style.display = 'inline'; document.getElementById('2306.12960v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.12960v3-abstract-full" style="display: none;"> CTA (Cherenkov Telescope Array) is the next generation ground-based observatory for gamma-ray astronomy at very-high energies. The Large-Sized Telescope prototype (LST-1) is located at the Northern site of CTA, on the Canary Island of La Palma. LSTs are designed to provide optimal performance in the lowest part of the energy range covered by CTA, down to $\simeq 20$ GeV. LST-1 started performing astronomical observations in November 2019, during its commissioning phase, and it has been taking data since then. We present the first LST-1 observations of the Crab Nebula, the standard candle of very-high energy gamma-ray astronomy, and use them, together with simulations, to assess the basic performance parameters of the telescope. The data sample consists of around 36 hours of observations at low zenith angles collected between November 2020 and March 2022. LST-1 has reached the expected performance during its commissioning period - only a minor adjustment of the preexisting simulations was needed to match the telescope behavior. The energy threshold at trigger level is estimated to be around 20 GeV, rising to $\simeq 30$ GeV after data analysis. Performance parameters depend strongly on energy, and on the strength of the gamma-ray selection cuts in the analysis: angular resolution ranges from 0.12 to 0.40 degrees, and energy resolution from 15 to 50%. Flux sensitivity is around 1.1% of the Crab Nebula flux above 250 GeV for a 50-h observation (12% for 30 minutes). The spectral energy distribution (in the 0.03 - 30 TeV range) and the light curve obtained for the Crab Nebula agree with previous measurements, considering statistical and systematic uncertainties. A clear periodic signal is also detected from the pulsar at the center of the Nebula. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.12960v3-abstract-full').style.display = 'none'; document.getElementById('2306.12960v3-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> 19 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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 in ApJ. v3: updated author list and acknowledgements, fixed typos and other minor issues</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.13898">arXiv:2305.13898</a> <span> [<a href="https://arxiv.org/pdf/2305.13898">pdf</a>, <a href="https://arxiv.org/format/2305.13898">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/10.3847/2041-8213/acd242">10.3847/2041-8213/acd242 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> X-ray Polarization of BL Lacertae in Outburst </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Peirson%2C+A+L">Abel L. Peirson</a>, <a href="/search/astro-ph?searchtype=author&query=Negro%2C+M">Michela Negro</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+E">Dawoon E. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Pacciani%2C+L">Luigi Pacciani</a>, <a href="/search/astro-ph?searchtype=author&query=Romani%2C+R+W">Roger W. Romani</a>, <a href="/search/astro-ph?searchtype=author&query=Wu%2C+K">Kinwah Wu</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Marco%2C+A">Alessandro Di Marco</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Lalla%2C+N">Niccolo Di Lalla</a>, <a href="/search/astro-ph?searchtype=author&query=Omodei%2C+N">Nicola Omodei</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Ivan Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Kouch%2C+P+M">Pouya M. Kouch</a>, <a href="/search/astro-ph?searchtype=author&query=Lindfors%2C+E">Elina Lindfors</a>, <a href="/search/astro-ph?searchtype=author&query=Aceituno%2C+F+J">Francisco Jose Aceituno</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M+I">Maria I. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Casanova%2C+V">Victor Casanova</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia-Comas%2C+M">Maya Garcia-Comas</a>, <a href="/search/astro-ph?searchtype=author&query=Agis-Gonzalez%2C+B">Beatriz Agis-Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Husillos%2C+C">Cesar Husillos</a>, <a href="/search/astro-ph?searchtype=author&query=Marchini%2C+A">Alessandro Marchini</a> , et al. (106 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="2305.13898v2-abstract-short" style="display: inline;"> We report the first $> 99\%$ confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/$纬$-ray outburst, a 287 ksec observation (2022 November 27-30) was taken using the Imaging X-ray Polarimetry Explorer ({\it IXPE}), together with contemporaneous multiwavelength observations from the Neil Gehrels {\it Swift} observatory and {\it XMM-Newton} in soft X-rays (0.3--10~keV), {\… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.13898v2-abstract-full').style.display = 'inline'; document.getElementById('2305.13898v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.13898v2-abstract-full" style="display: none;"> We report the first $> 99\%$ confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/$纬$-ray outburst, a 287 ksec observation (2022 November 27-30) was taken using the Imaging X-ray Polarimetry Explorer ({\it IXPE}), together with contemporaneous multiwavelength observations from the Neil Gehrels {\it Swift} observatory and {\it XMM-Newton} in soft X-rays (0.3--10~keV), {\it NuSTAR} in hard X-rays (3--70~keV), and optical polarization from the Calar Alto, and Perkins Telescope observatories. Our contemporaneous X-ray data suggest that the {\it IXPE} energy band is at the crossover between the low- and high-frequency blazar emission humps. The source displays significant variability during the observation, and we measure polarization in three separate time bins. Contemporaneous X-ray spectra allow us to determine the relative contribution from each emission hump. We find $>99\%$ confidence X-ray polarization $螤_{2-4{\rm keV}} = 21.7^{+5.6}_{-7.9}\%$ and electric vector polarization angle $蠄_{2-4{\rm keV}} = -28.7 \pm 8.7^{\circ}$ in the time bin with highest estimated synchrotron flux contribution. We discuss possible implications of our observations, including previous {\it IXPE} BL Lacertae pointings, tentatively concluding that synchrotron self-Compton emission dominates over hadronic emission processes during the observed epochs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.13898v2-abstract-full').style.display = 'none'; document.getElementById('2305.13898v2-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 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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 to ApJL. 16 pages, 8 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.13497">arXiv:2305.13497</a> <span> [<a href="https://arxiv.org/pdf/2305.13497">pdf</a>, <a href="https://arxiv.org/format/2305.13497">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"> Discovery of X-ray polarization angle rotation in active galaxy Mrk 421 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Ehlert%2C+S+R">Steven R. Ehlert</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+E">Dawoon E. Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Donnarumma%2C+I">Immacolata Donnarumma</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">Fabrizio Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Kiehlmann%2C+S">Sebastian Kiehlmann</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Muleri%2C+F">Fabio Muleri</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Puccetti%2C+S">Simonetta Puccetti</a>, <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Perri%2C+M">Matteo Perri</a>, <a href="/search/astro-ph?searchtype=author&query=Pacciani%2C+L">Luigi Pacciani</a>, <a href="/search/astro-ph?searchtype=author&query=Negro%2C+M">Michela Negro</a>, <a href="/search/astro-ph?searchtype=author&query=Romani%2C+R+W">Roger W. Romani</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Marco%2C+A">Alessandro Di Marco</a>, <a href="/search/astro-ph?searchtype=author&query=Blinov%2C+D">Dmitry Blinov</a>, <a href="/search/astro-ph?searchtype=author&query=Bourbah%2C+I+G">Ioakeim G. Bourbah</a>, <a href="/search/astro-ph?searchtype=author&query=Kontopodis%2C+E">Evangelos Kontopodis</a>, <a href="/search/astro-ph?searchtype=author&query=Mandarakas%2C+N">Nikos Mandarakas</a>, <a href="/search/astro-ph?searchtype=author&query=Romanopoulos%2C+S">Stylianos Romanopoulos</a>, <a href="/search/astro-ph?searchtype=author&query=Skalidis%2C+R">Raphael Skalidis</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="2305.13497v1-abstract-short" style="display: inline;"> The magnetic field conditions in astrophysical relativistic jets can be probed by multiwavelength polarimetry, which has been recently extended to X-rays. For example, one can track how the magnetic field changes in the flow of the radiating particles by observing rotations of the electric vector position angle $唯$. Here we report the discovery of a $唯_{\mathrm x}$ rotation in the X-ray band in th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.13497v1-abstract-full').style.display = 'inline'; document.getElementById('2305.13497v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.13497v1-abstract-full" style="display: none;"> The magnetic field conditions in astrophysical relativistic jets can be probed by multiwavelength polarimetry, which has been recently extended to X-rays. For example, one can track how the magnetic field changes in the flow of the radiating particles by observing rotations of the electric vector position angle $唯$. Here we report the discovery of a $唯_{\mathrm x}$ rotation in the X-ray band in the blazar Mrk 421 at an average flux state. Across the 5 days of Imaging X-ray Polarimetry Explorer (IXPE) observations of 4-6 and 7-9 June 2022, $唯_{\mathrm x}$ rotated in total by $\geq360^\circ$. Over the two respective date ranges, we find constant, within uncertainties, rotation rates ($80 \pm 9$ and $91 \pm 8 ^\circ/\rm day$) and polarization degrees ($螤_{\mathrm x}=10\%\pm1\%$). Simulations of a random walk of the polarization vector indicate that it is unlikely that such rotation(s) are produced by a stochastic process. The X-ray emitting site does not completely overlap the radio/infrared/optical emission sites, as no similar rotation of $唯$ was observed in quasi-simultaneous data at longer wavelengths. We propose that the observed rotation was caused by a helical magnetic structure in the jet, illuminated in the X-rays by a localized shock propagating along this helix. The optically emitting region likely lies in a sheath surrounding an inner spine where the X-ray radiation is released. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.13497v1-abstract-full').style.display = 'none'; document.getElementById('2305.13497v1-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 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.10527">arXiv:2212.10527</a> <span> [<a href="https://arxiv.org/pdf/2212.10527">pdf</a>, <a href="https://arxiv.org/format/2212.10527">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/PhysRevLett.130.061002">10.1103/PhysRevLett.130.061002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for Gamma-ray Spectral Lines from Dark Matter Annihilation up to 100 TeV towards the Galactic Center 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=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a> , et al. (188 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="2212.10527v1-abstract-short" style="display: inline;"> Line-like features in TeV $纬$-rays constitute a ''smoking gun'' for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables the search for TeV spectral features in immediate association with a dense dark matter reservoir at a sensitivity out of reach for satellite $纬$-ray detectors, and direct detection and collider experime… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.10527v1-abstract-full').style.display = 'inline'; document.getElementById('2212.10527v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.10527v1-abstract-full" style="display: none;"> Line-like features in TeV $纬$-rays constitute a ''smoking gun'' for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables the search for TeV spectral features in immediate association with a dense dark matter reservoir at a sensitivity out of reach for satellite $纬$-ray detectors, and direct detection and collider experiments. We report on 223 hours of observations of the Galactic Center region with the MAGIC stereoscopic telescope system reaching $纬$-ray energies up to 100 TeV. We improved the sensitivity to spectral lines at high energies using large-zenith-angle observations and a novel background modeling method within a maximum-likelihood analysis in the energy domain. No line-like spectral feature is found in our analysis. Therefore, we constrain the cross section for dark matter annihilation into two photons to $\langle 蟽v \rangle \lesssim 5 \times 10^{-28}\,\mathrm{cm^3\,s^{-1}}$ at 1 TeV and $\langle 蟽v \rangle \lesssim 1 \times 10^{-25}\,\mathrm{cm^3\,s^{-1}}$ at 100 TeV, achieving the best limits to date for a dark matter mass above 20 TeV and a cuspy dark matter profile at the Galactic Center. Finally, we use the derived limits for both cuspy and cored dark matter profiles to constrain supersymmetric wino models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.10527v1-abstract-full').style.display = 'none'; document.getElementById('2212.10527v1-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 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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 Phys. Rev. Lett., includes Supplemental materials. 9+4 pages, 3+3 figures, 3 tables. Corresponding authors: T. Inada, D. Kerszberg, M. H眉tten</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> KEK-TH-2487, KEK-Cosmo-0307 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.15321">arXiv:2211.15321</a> <span> [<a href="https://arxiv.org/pdf/2211.15321">pdf</a>, <a href="https://arxiv.org/format/2211.15321">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202244931">10.1051/0004-6361/202244931 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> MAGIC observations provide compelling evidence of the hadronic multi-TeV emission from the putative PeVatron SNR G106.3+2.7 </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=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a> , et al. (192 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="2211.15321v1-abstract-short" style="display: inline;"> The SNR G106.3+2.7, detected at 1--100 TeV energies by different $纬$-ray facilities, is one of the most promising PeVatron candidates. This SNR has a cometary shape which can be divided into a head and a tail region with different physical conditions. However, it is not identified in which region the 100 TeV emission is produced due to the limited position accuracy and/or angular resolution of exi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.15321v1-abstract-full').style.display = 'inline'; document.getElementById('2211.15321v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.15321v1-abstract-full" style="display: none;"> The SNR G106.3+2.7, detected at 1--100 TeV energies by different $纬$-ray facilities, is one of the most promising PeVatron candidates. This SNR has a cometary shape which can be divided into a head and a tail region with different physical conditions. However, it is not identified in which region the 100 TeV emission is produced due to the limited position accuracy and/or angular resolution of existing observational data. Additionally, it remains unclear whether the origin of the $纬$-ray emission is leptonic or hadronic. With the better angular resolution provided by these new MAGIC data compared to earlier $纬$-ray datasets, we aim to reveal the acceleration site of PeV particles and the emission mechanism by resolving the SNR G106.3+2.7 with 0.1$^\circ$ resolution at TeV energies. We detected extended $纬$-ray emission spatially coincident with the radio continuum emission at the head and tail of SNR G106.3+2.7. The fact that we detected a significant $纬$-ray emission with energies above 6.0 TeV from the tail region only suggests that the emissions above 10 TeV, detected with air shower experiments (Milagro, HAWC, Tibet AS$纬$ and LHAASO), are emitted only from the SNR tail. Under this assumption, the multi-wavelength spectrum of the head region can be explained with either hadronic or leptonic models, while the leptonic model for the tail region is in contradiction with the emission above 10 TeV and X-rays. In contrast, the hadronic model could reproduce the observed spectrum at the tail by assuming a proton spectrum with a cutoff energy of $\sim 1$ PeV for the tail region. Such a high energy emission in this middle-aged SNR (4--10 kyr) can be explained by considering the scenario that protons escaping from the SNR in the past interact with surrounding dense gases at present. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.15321v1-abstract-full').style.display = 'none'; document.getElementById('2211.15321v1-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 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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 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 671, A12 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.13764">arXiv:2211.13764</a> <span> [<a href="https://arxiv.org/pdf/2211.13764">pdf</a>, <a href="https://arxiv.org/format/2211.13764">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/10.3847/2041-8213/aca281">10.3847/2041-8213/aca281 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> X-ray Polarization Observations of BL Lacertae </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Middei%2C+R">Riccardo Middei</a>, <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Perri%2C+M">Matteo Perri</a>, <a href="/search/astro-ph?searchtype=author&query=Puccetti%2C+S">Simonetta Puccetti</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">Elisabetta Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Ehlert%2C+S+R">Steven R. Ehlert</a>, <a href="/search/astro-ph?searchtype=author&query=Madejski%2C+G">Grzegorz Madejski</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Muleri%2C+F">Fabio Muleri</a>, <a href="/search/astro-ph?searchtype=author&query=Negro%2C+M">Michela Negro</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Ag%C3%ADs-Gonz%C3%A1lez%2C+B">Beatriz Ag铆s-Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M+I">Maria I. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Casanova%2C+V">V铆ctor Casanova</a>, <a href="/search/astro-ph?searchtype=author&query=Garc%C3%ADa-Comas%2C+M">Maya Garc铆a-Comas</a>, <a href="/search/astro-ph?searchtype=author&query=Husillos%2C+C">C茅sar Husillos</a>, <a href="/search/astro-ph?searchtype=author&query=Marchini%2C+A">Alessandro Marchini</a>, <a href="/search/astro-ph?searchtype=author&query=Sota%2C+A">Alfredo Sota</a>, <a href="/search/astro-ph?searchtype=author&query=Kouch%2C+P+M">Pouya M. Kouch</a>, <a href="/search/astro-ph?searchtype=author&query=Borman%2C+G+A">George A. Borman</a>, <a href="/search/astro-ph?searchtype=author&query=Kopatskaya%2C+E+N">Evgenia N. Kopatskaya</a> , et al. (121 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="2211.13764v1-abstract-short" style="display: inline;"> Blazars are a class of jet-dominated active galactic nuclei with a typical double-humped spectral energy distribution. It is of common consensus the Synchrotron emission to be responsible for the low frequency peak, while the origin of the high frequency hump is still debated. The analysis of X-rays and their polarization can provide a valuable tool to understand the physical mechanisms responsibl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.13764v1-abstract-full').style.display = 'inline'; document.getElementById('2211.13764v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.13764v1-abstract-full" style="display: none;"> Blazars are a class of jet-dominated active galactic nuclei with a typical double-humped spectral energy distribution. It is of common consensus the Synchrotron emission to be responsible for the low frequency peak, while the origin of the high frequency hump is still debated. The analysis of X-rays and their polarization can provide a valuable tool to understand the physical mechanisms responsible for the origin of high-energy emission of blazars. We report the first observations of BL Lacertae performed with the Imaging X-ray Polarimetry Explorer ({IXPE}), from which an upper limit to the polarization degree $螤_X<$12.6\% was found in the 2-8 keV band. We contemporaneously measured the polarization in radio, infrared, and optical wavelengths. Our multiwavelength polarization analysis disfavors a significant contribution of proton synchrotron radiation to the X-ray emission at these epochs. Instead, it supports a leptonic origin for the X-ray emission in BL Lac. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.13764v1-abstract-full').style.display = 'none'; document.getElementById('2211.13764v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">17 pages, 5 figures, accepted for publication in ApJL</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2023, ApJ Letters, 942, L10 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.13268">arXiv:2211.13268</a> <span> [<a href="https://arxiv.org/pdf/2211.13268">pdf</a>, <a href="https://arxiv.org/format/2211.13268">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202244477">10.1051/0004-6361/202244477 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Long-term multi-wavelength study of 1ES 0647+250 </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=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</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=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</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> , et al. (195 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="2211.13268v1-abstract-short" style="display: inline;"> The BL Lac object 1ES 0647+250 is one of the few distant $纬$-ray emitting blazars detected at very high energies (VHE, $\gtrsim$100 GeV) during a non-flaring state. It was detected with the MAGIC telescopes during its low activity in the years 2009-2011, as well as during three flaring activities in the years 2014, 2019 and 2020, with the highest VHE flux in the latter epoch. An extensive multi-in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.13268v1-abstract-full').style.display = 'inline'; document.getElementById('2211.13268v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.13268v1-abstract-full" style="display: none;"> The BL Lac object 1ES 0647+250 is one of the few distant $纬$-ray emitting blazars detected at very high energies (VHE, $\gtrsim$100 GeV) during a non-flaring state. It was detected with the MAGIC telescopes during its low activity in the years 2009-2011, as well as during three flaring activities in the years 2014, 2019 and 2020, with the highest VHE flux in the latter epoch. An extensive multi-instrument data set was collected within several coordinated observing campaigns throughout these years. We aim to characterise the long-term multi-band flux variability of 1ES 0647+250, as well as its broadband spectral energy distribution (SED) during four distinct activity states selected in four different epochs, in order to constrain the physical parameters of the blazar emission region under certain assumptions. We evaluate the variability and correlation of the emission in the different energy bands with the fractional variability and the Z-transformed Discrete Correlation Function, as well as its spectral evolution in X-rays and $纬$ rays. Owing to the controversy in the redshift measurements of 1ES 0647+250 reported in the literature, we also estimate its distance in an indirect manner through the comparison of the GeV and TeV spectra from simultaneous observations with Fermi-LAT and MAGIC during the strongest flaring activity detected to date. Moreover, we interpret the SEDs from the four distinct activity states within the framework of one-component and two-component leptonic models, proposing specific scenarios that are able to reproduce the available multi-instrument data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.13268v1-abstract-full').style.display = 'none'; document.getElementById('2211.13268v1-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 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">20 pages, 7 figures. Accepted in A&A. Corresponding authors: Jorge Otero-Santos; Daniel Morcuende; Vandad Fallah Ramazani; Daniela Dorner; David Paneque (mailto: contact.magic@mpp.mpg.de)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 670, A49 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.05659">arXiv:2210.05659</a> <span> [<a href="https://arxiv.org/pdf/2210.05659">pdf</a>, <a href="https://arxiv.org/format/2210.05659">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/10.1103/PhysRevLett.131.251001">10.1103/PhysRevLett.131.251001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observability of the very-high-energy emission from GRB 221009A </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Galanti%2C+G">Giorgio Galanti</a>, <a href="/search/astro-ph?searchtype=author&query=Nava%2C+L">Lara Nava</a>, <a href="/search/astro-ph?searchtype=author&query=Roncadelli%2C+M">Marco Roncadelli</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">Fabrizio Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</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="2210.05659v8-abstract-short" style="display: inline;"> The LHAASO Collaboration detected the gamma ray burst GRB 221009A at energies above $500 \, {\rm GeV}$ with a tail extending up to $18 \, \rm TeV$, whose spectral analysis has presently been performed up to $7 \, \rm TeV$ for the lower energy instrument LHAASO-WCDA only, with no indication of a cutoff. Soon thereafter, Carpet-2 at Baksan Neutrino Observatory reported the observation of an air show… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.05659v8-abstract-full').style.display = 'inline'; document.getElementById('2210.05659v8-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.05659v8-abstract-full" style="display: none;"> The LHAASO Collaboration detected the gamma ray burst GRB 221009A at energies above $500 \, {\rm GeV}$ with a tail extending up to $18 \, \rm TeV$, whose spectral analysis has presently been performed up to $7 \, \rm TeV$ for the lower energy instrument LHAASO-WCDA only, with no indication of a cutoff. Soon thereafter, Carpet-2 at Baksan Neutrino Observatory reported the observation of an air shower consistent with being caused by a photon of energy $251 \, {\rm TeV}$ from the same GRB. Given the source redshift $z=0.151$, the expected attenuation due to the extragalactic background light is very severe so that these detections have proven very hard to explain. In this Letter, we show that the existence of axion-like-particles (ALPs) with mass $m_a \simeq (10^{-11}-10^{-7}) \, {\rm eV}$ and two-photon coupling $g_{a 纬纬} \simeq (3-5) \times 10^{-12} \, {\rm GeV}^{- 1}$ strongly reduce the optical depth of TeV photons, thus explaining the observations. Our ALPs meet all available constraints, are consistent with two previous hints at their existence and are good candidates for cold dark matter. Moreover, we show that Lorentz Invariance Violation (LIV) can explain the Carpet-2 result but not the LHAASO observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.05659v8-abstract-full').style.display = 'none'; document.getElementById('2210.05659v8-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 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">22 pages, 13 figures, This version matches the published paper: Phys. Rev. Lett. 131, 251001 (2023)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 131, 251001 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.03321">arXiv:2210.03321</a> <span> [<a href="https://arxiv.org/pdf/2210.03321">pdf</a>, <a href="https://arxiv.org/format/2210.03321">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202244126">10.1051/0004-6361/202244126 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A lower bound on intergalactic magnetic fields from time variability of 1ES 0229+200 from MAGIC and Fermi/LAT observations </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=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</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=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</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> , et al. (184 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="2210.03321v1-abstract-short" style="display: inline;"> Extended and delayed emission around distant TeV sources induced by the effects of propagation of gamma rays through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF). We search for delayed GeV emission from the hard-spectrum TeV blazar 1ES 0229+200 with the goal to detect or constrain the IGMF-dependent secondary flux generated during the propagat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.03321v1-abstract-full').style.display = 'inline'; document.getElementById('2210.03321v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.03321v1-abstract-full" style="display: none;"> Extended and delayed emission around distant TeV sources induced by the effects of propagation of gamma rays through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF). We search for delayed GeV emission from the hard-spectrum TeV blazar 1ES 0229+200 with the goal to detect or constrain the IGMF-dependent secondary flux generated during the propagation of TeV gamma rays through the intergalactic medium. We analyze the most recent MAGIC observations over a 5 year time span and complement them with historic data of the H.E.S.S. and VERITAS telescopes along with a 12-year long exposure of the Fermi/LAT telescope. We use them to trace source evolution in the GeV-TeV band over one-and-a-half decade in time. We use Monte Carlo simulations to predict the delayed secondary gamma-ray flux, modulated by the source variability, as revealed by TeV-band observations. We then compare these predictions for various assumed IGMF strengths to all available measurements of the gamma-ray flux evolution. We find that the source flux in the energy range above 200 GeV experiences variations around its average on the 14 years time span of observations. No evidence for the flux variability is found in 1-100 GeV energy range accessible to Fermi/LAT. Non-detection of variability due to delayed emission from electromagnetic cascade developing in the intergalactic medium imposes a lower bound of B>1.8e-17 G for long correlation length IGMF and B>1e-14 G for an IGMF of the cosmological origin. Though weaker than the one previously derived from the analysis of Fermi/LAT data, this bound is more robust, being based on a conservative intrinsic source spectrum estimate and accounting for the details of source variability in the TeV energy band. We discuss implications of this bound for cosmological magnetic fields which might explain the baryon asymmetry of the Universe. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.03321v1-abstract-full').style.display = 'none'; document.getElementById('2210.03321v1-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> 7 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">10 pages, 5 figures, accepted to A&A. Corresponding authors: Ievgen Vovk, Paolo Da Vela (mailto:contact.magic@mpp.mpg.de) and Andrii Neronov (mailto:Andrii.Neronov@unige.ch)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 670, A145 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.02547">arXiv:2210.02547</a> <span> [<a href="https://arxiv.org/pdf/2210.02547">pdf</a>, <a href="https://arxiv.org/format/2210.02547">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/acc181">10.3847/1538-4365/acc181 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-messenger characterization of Mrk 501 during historically low X-ray and $纬$-ray activity </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=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">I. Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a> , et al. (300 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="2210.02547v3-abstract-short" style="display: inline;"> We study the broadband emission of Mrk 501 using multi-wavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi-LAT, NuSTAR, Swift, GASP-WEBT, and OVRO. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wavebands, with the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.02547v3-abstract-full').style.display = 'inline'; document.getElementById('2210.02547v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.02547v3-abstract-full" style="display: none;"> We study the broadband emission of Mrk 501 using multi-wavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi-LAT, NuSTAR, Swift, GASP-WEBT, and OVRO. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wavebands, with the highest occurring at X-rays and very-high-energy (VHE) $纬$-rays. A significant correlation ($>$3$蟽$) between X-rays and VHE $纬$-rays is measured, supporting leptonic scenarios to explain the variable parts of the emission, also during low activity. This is further supported when we extend our data from 2008 to 2020, and identify, for the first time, significant correlations between Swift-XRT and Fermi-LAT. We additionally find correlations between high-energy $纬$-rays and radio, with the radio lagging by more than 100 days, placing the $纬$-ray emission zone upstream of the radio-bright regions in the jet. Furthermore, Mrk 501 showed a historically low activity in X-rays and VHE $纬$-rays from mid-2017 to mid-2019 with a stable VHE flux ($>$0.2 TeV) of 5% the emission of the Crab Nebula. The broadband spectral energy distribution (SED) of this 2-year-long low-state, the potential baseline emission of Mrk 501, can be characterized with one-zone leptonic models, and with (lepto)-hadronic models fulfilling neutrino flux constraints from IceCube. We explore the time evolution of the SED towards the low-state, revealing that the stable baseline emission may be ascribed to a standing shock, and the variable emission to an additional expanding or traveling shock. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.02547v3-abstract-full').style.display = 'none'; document.getElementById('2210.02547v3-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 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">55 pages, 30 figures, 14 tables, accepted by APJS. Corresponding authors are L. Heckmann, D. Paneque, S. Gasparyan, M. Cerruti, and N. Sahakyan</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJS 266 37 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.09785">arXiv:2209.09785</a> <span> [<a href="https://arxiv.org/pdf/2209.09785">pdf</a>, <a href="https://arxiv.org/format/2209.09785">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/stac2686">10.1093/mnras/stac2686 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gamma-ray observations of MAXI J1820+070 during the 2018 outburst </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abe%2C+H">H. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+S">S. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Baxter%2C+J">J. Baxter</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=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</a> , et al. (418 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="2209.09785v2-abstract-short" style="display: inline;"> MAXI J1820+070 is a low-mass X-ray binary with a black hole as a compact object. This binary underwent an exceptionally bright X-ray outburst from March to October 2018, showing evidence of a non-thermal particle population through its radio emission during this whole period. The combined results of 59.5 hours of observations of the MAXI J1820+070 outburst with the H.E.S.S., MAGIC and VERITAS expe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.09785v2-abstract-full').style.display = 'inline'; document.getElementById('2209.09785v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.09785v2-abstract-full" style="display: none;"> MAXI J1820+070 is a low-mass X-ray binary with a black hole as a compact object. This binary underwent an exceptionally bright X-ray outburst from March to October 2018, showing evidence of a non-thermal particle population through its radio emission during this whole period. The combined results of 59.5 hours of observations of the MAXI J1820+070 outburst with the H.E.S.S., MAGIC and VERITAS experiments at energies above 200 GeV are presented, together with Fermi-LAT data between 0.1 and 500 GeV, and multiwavelength observations from radio to X-rays. Gamma-ray emission is not detected from MAXI J1820+070, but the obtained upper limits and the multiwavelength data allow us to put meaningful constraints on the source properties under reasonable assumptions regarding the non-thermal particle population and the jet synchrotron spectrum. In particular, it is possible to show that, if a high-energy gamma-ray emitting region is present during the hard state of the source, its predicted flux should be at most a factor of 20 below the obtained Fermi-LAT upper limits, and closer to them for magnetic fields significantly below equipartition. During the state transitions, under the plausible assumption that electrons are accelerated up to ~ 500 GeV, the multiwavelength data and the gamma-ray upper limits lead consistently to the conclusion that a potential high-energy and very-high-energy gamma-ray emitting region should be located at a distance from the black hole ranging between 10^11 and 10^13 cm. Similar outbursts from low-mass X-ray binaries might be detectable in the near future with upcoming instruments such as CTA. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.09785v2-abstract-full').style.display = 'none'; document.getElementById('2209.09785v2-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 20 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">15 pages, 5 figures. Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.06227">arXiv:2209.06227</a> <span> [<a href="https://arxiv.org/pdf/2209.06227">pdf</a>, <a href="https://arxiv.org/format/2209.06227">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/s41586-022-05338-0">10.1038/s41586-022-05338-0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Polarized Blazar X-rays imply particle acceleration in shocks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Liodakis%2C+I">Ioannis Liodakis</a>, <a href="/search/astro-ph?searchtype=author&query=Marscher%2C+A+P">Alan P. Marscher</a>, <a href="/search/astro-ph?searchtype=author&query=Agudo%2C+I">Iv谩n Agudo</a>, <a href="/search/astro-ph?searchtype=author&query=Berdyugin%2C+A+V">Andrei V. Berdyugin</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M+I">Maria I. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Borman%2C+G+A">George A. Borman</a>, <a href="/search/astro-ph?searchtype=author&query=Casadio%2C+C">Carolina Casadio</a>, <a href="/search/astro-ph?searchtype=author&query=Casanova%2C+V">V铆ctor Casanova</a>, <a href="/search/astro-ph?searchtype=author&query=Cavazzuti%2C+E">Elisabetta Cavazzuti</a>, <a href="/search/astro-ph?searchtype=author&query=Cavero%2C+N+R">Nicole Rodriguez Cavero</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gesu%2C+L">Laura Di Gesu</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Lalla%2C+N">Niccol贸 Di Lalla</a>, <a href="/search/astro-ph?searchtype=author&query=Donnarumma%2C+I">Immacolata Donnarumma</a>, <a href="/search/astro-ph?searchtype=author&query=Ehlert%2C+S+R">Steven R. Ehlert</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">Manel Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Escudero%2C+J">Juan Escudero</a>, <a href="/search/astro-ph?searchtype=author&query=Garc%C3%ADa-Comas%2C+M">Maya Garc铆a-Comas</a>, <a href="/search/astro-ph?searchtype=author&query=Ag%C3%ADs-Gonz%C3%A1lez%2C+B">Beatriz Ag铆s-Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Husillos%2C+C">C茅sar Husillos</a>, <a href="/search/astro-ph?searchtype=author&query=Jormanainen%2C+J">Jenni Jormanainen</a>, <a href="/search/astro-ph?searchtype=author&query=Jorstad%2C+S+G">Svetlana G. Jorstad</a>, <a href="/search/astro-ph?searchtype=author&query=Kagitani%2C+M">Masato Kagitani</a>, <a href="/search/astro-ph?searchtype=author&query=Kopatskaya%2C+E+N">Evgenia N. Kopatskaya</a>, <a href="/search/astro-ph?searchtype=author&query=Kravtsov%2C+V">Vadim Kravtsov</a> , et al. (103 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="2209.06227v2-abstract-short" style="display: inline;"> Most of the light from blazars, active galactic nuclei with jets of magnetized plasma that point nearly along the line of sight, is produced by high-energy particles, up to $\sim 1$ TeV. Although the jets are known to be ultimately powered by a supermassive black hole, how the particles are accelerated to such high energies has been an unanswered question. The process must be related to the magnet… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.06227v2-abstract-full').style.display = 'inline'; document.getElementById('2209.06227v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.06227v2-abstract-full" style="display: none;"> Most of the light from blazars, active galactic nuclei with jets of magnetized plasma that point nearly along the line of sight, is produced by high-energy particles, up to $\sim 1$ TeV. Although the jets are known to be ultimately powered by a supermassive black hole, how the particles are accelerated to such high energies has been an unanswered question. The process must be related to the magnetic field, which can be probed by observations of the polarization of light from the jets. Measurements of the radio to optical polarization - the only range available until now - probe extended regions of the jet containing particles that left the acceleration site days to years earlier (Jorstad et al., 2005; Marin et al., 2018; Blinov et al., 2021), and hence do not directly explore the acceleration mechanism, as could X-ray measurements. Here we report the detection of X-ray polarization from the blazar Markarian~501 (Mrk~501). We measure an X-ray linear polarization degree $螤_X \sim10\%$, a factor of $\sim2$ higher than the value at optical wavelengths, with a polarization angle parallel to the radio jet. This points to a shock front as the source of particle acceleration, and also implies that the plasma becomes increasingly turbulent with distance from the shock. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.06227v2-abstract-full').style.display = 'none'; document.getElementById('2209.06227v2-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 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 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">34 pages, 4 figures, 4 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2022, Nature, 611, 677-681 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.03177">arXiv:2208.03177</a> <span> [<a href="https://arxiv.org/pdf/2208.03177">pdf</a>, <a href="https://arxiv.org/format/2208.03177">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/10.1016/j.jheap.2022.05.005">10.1016/j.jheap.2022.05.005 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> ASTRI Mini-Array Core Science at the Observatorio del Teide </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Vercellone%2C+S">S. Vercellone</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</a>, <a href="/search/astro-ph?searchtype=author&query=Burtovoi%2C+A">A. Burtovoi</a>, <a href="/search/astro-ph?searchtype=author&query=Cardillo%2C+M">M. Cardillo</a>, <a href="/search/astro-ph?searchtype=author&query=Catalano%2C+O">O. Catalano</a>, <a href="/search/astro-ph?searchtype=author&query=Franceschini%2C+A">A. Franceschini</a>, <a href="/search/astro-ph?searchtype=author&query=Lombardi%2C+S">S. Lombardi</a>, <a href="/search/astro-ph?searchtype=author&query=Nava%2C+L">L. Nava</a>, <a href="/search/astro-ph?searchtype=author&query=Pintore%2C+F">F. Pintore</a>, <a href="/search/astro-ph?searchtype=author&query=Stamerra%2C+A">A. Stamerra</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">F. Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Zampieri%2C+L">L. Zampieri</a>, <a href="/search/astro-ph?searchtype=author&query=Batista%2C+R+A">R. Alves Batista</a>, <a href="/search/astro-ph?searchtype=author&query=Amato%2C+E">E. Amato</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=Gonzalez%2C+J+B">J. Becerra Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">G. Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Bottcher%2C+M">M. Bottcher</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">G. Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Compagnino%2C+A+A">A. A. Compagnino</a>, <a href="/search/astro-ph?searchtype=author&query=Crestan%2C+S">S. Crestan</a>, <a href="/search/astro-ph?searchtype=author&query=Ai%2C+A+D">A. D Ai</a>, <a href="/search/astro-ph?searchtype=author&query=Fiori%2C+M">M. Fiori</a>, <a href="/search/astro-ph?searchtype=author&query=Galanti%2C+G">G. Galanti</a> , et al. (62 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2208.03177v1-abstract-short" style="display: inline;"> The ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) Project led by the Italian National Institute for Astrophysics (INAF) is developing and will deploy at the Observatorio del Teide a mini-array (ASTRI Mini-Array) composed of nine telescopes similar to the small-size dual-mirror Schwarzschild-Couder telescope (ASTRI-Horn) currently operating on the slopes of Mt. Etna in Sicily.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.03177v1-abstract-full').style.display = 'inline'; document.getElementById('2208.03177v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.03177v1-abstract-full" style="display: none;"> The ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) Project led by the Italian National Institute for Astrophysics (INAF) is developing and will deploy at the Observatorio del Teide a mini-array (ASTRI Mini-Array) composed of nine telescopes similar to the small-size dual-mirror Schwarzschild-Couder telescope (ASTRI-Horn) currently operating on the slopes of Mt. Etna in Sicily. The ASTRI Mini-Array will surpass the current Cherenkov telescope array differential sensitivity above a few tera-electronvolt (TeV), extending the energy band well above hundreds of TeV. This will allow us to explore a new window of the electromagnetic spectrum, by convolving the sensitivity performance with excellent angular and energy resolution figures. In this paper we describe the Core Science that we will address during the first four years of operation, providing examples of the breakthrough results that we will obtain when dealing with current open questions, such as the acceleration of cosmic rays, cosmology and fundamental physics and the new window, for the TeV energy band, of the time-domain astrophysics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.03177v1-abstract-full').style.display = 'none'; document.getElementById('2208.03177v1-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 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">Published in Journal of High Energy Astrophysics. 46 Figures, 7 Tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of High Energy Astrophysics, Volume 35, August 2022, Pages 1-42 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.07681">arXiv:2202.07681</a> <span> [<a href="https://arxiv.org/pdf/2202.07681">pdf</a>, <a href="https://arxiv.org/format/2202.07681">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/s41550-022-01640-z">10.1038/s41550-022-01640-z <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Proton acceleration in thermonuclear nova explosions revealed by gamma rays </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=Acciari%2C+V+A">V. A. Acciari</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</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=Bellizzi%2C+L">L. Bellizzi</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</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=B%C3%B6kenkamp%2C+H">H. B枚kenkamp</a> , et al. (186 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="2202.07681v3-abstract-short" style="display: inline;"> Classical novae are cataclysmic binary star systems in which the matter of a companion star is accreted on a white dwarf (WD). Accumulation of hydrogen in a layer eventually causes a thermonuclear explosion on the surface of the WD, brightening the WD to ~10^5 solar luminosities and triggering ejection of the accumulated matter.They provide extreme conditions required to accelerate particles, elec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.07681v3-abstract-full').style.display = 'inline'; document.getElementById('2202.07681v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.07681v3-abstract-full" style="display: none;"> Classical novae are cataclysmic binary star systems in which the matter of a companion star is accreted on a white dwarf (WD). Accumulation of hydrogen in a layer eventually causes a thermonuclear explosion on the surface of the WD, brightening the WD to ~10^5 solar luminosities and triggering ejection of the accumulated matter.They provide extreme conditions required to accelerate particles, electrons or protons, to high energies. Here we present the detection of gamma rays by the MAGIC telescopes from the 2021 outburst of RS Ophiuchi (RS Oph), a recurrent nova with a red giant (RG) companion, that allowed us, for the first time, to accurately characterize the emission from a nova in the 60 GeV to 250 GeV energy range. The theoretical interpretation of the combined Fermi-LAT and MAGIC data suggests that protons are accelerated to hundreds of GeV in the nova shock. Such protons should create bubbles of enhanced Cosmic Ray density, on the order of 10 pc, from the recurrent novae. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.07681v3-abstract-full').style.display = 'none'; document.getElementById('2202.07681v3-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 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 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">THIS VERSION IS AFTER THE JOURNAL REVIEW</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Astronomy, Volume 6, p. 689-697 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.02600">arXiv:2202.02600</a> <span> [<a href="https://arxiv.org/pdf/2202.02600">pdf</a>, <a href="https://arxiv.org/format/2202.02600">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/ac531d">10.3847/1538-4357/ac531d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigating the blazar TXS 0506+056 through sharp multi-wavelength eyes during 2017-2019 </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=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=Aniello%2C+T">T. Aniello</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</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=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</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=B%C3%B6kenkamp%2C+H">H. B枚kenkamp</a> , et al. (192 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="2202.02600v2-abstract-short" style="display: inline;"> The blazar TXS 0506+056 got into the spotlight of the astrophysical community in September 2017, when a high-energy neutrino detected by IceCube (IceCube-170922A) was associated at the 3 $蟽$ level to a $纬$-ray flare from this source. This multi-messenger photon-neutrino association remains, as per today, the most significant one ever observed. TXS 0506+056 was a poorly studied object before the Ic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.02600v2-abstract-full').style.display = 'inline'; document.getElementById('2202.02600v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.02600v2-abstract-full" style="display: none;"> The blazar TXS 0506+056 got into the spotlight of the astrophysical community in September 2017, when a high-energy neutrino detected by IceCube (IceCube-170922A) was associated at the 3 $蟽$ level to a $纬$-ray flare from this source. This multi-messenger photon-neutrino association remains, as per today, the most significant one ever observed. TXS 0506+056 was a poorly studied object before the IceCube-170922A event. To better characterize its broad-band emission, we organized a multi-wavelength campaign lasting 16 months (November 2017 to February 2019), covering the radio-band (Mets盲hovi, OVRO), the optical/UV (ASAS-SN, KVA, REM, Swift/UVOT), the X-rays (Swift/XRT, NuSTAR), the high-energy $纬$ rays (Fermi/LAT) and the very-high-energy (VHE) $纬$ rays (MAGIC). In $纬$ rays, the behaviour of the source was significantly different from the 2017 one: MAGIC observations show the presence of flaring activity during December 2018, while the source only shows an excess at the 4$蟽$ level during the rest of the campaign (74 hours of accumulated exposure); Fermi/LAT observations show several short (days-to-week timescale) flares, different from the long-term brightening of 2017. No significant flares are detected at lower energies. The radio light curve shows an increasing flux trend, not seen in other wavelengths. We model the multi-wavelength spectral energy distributions in a lepto-hadronic scenario, in which the hadronic emission emerges as Bethe-Heitler and pion-decay cascade in the X-rays and VHE $纬$ rays. According to the model presented here, the December 2018 $纬$-ray flare was connected to a neutrino emission that was too brief and not bright enough to be detected by current neutrino instruments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.02600v2-abstract-full').style.display = 'none'; document.getElementById('2202.02600v2-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> 1 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 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">18 pages, 6 figures; V2 to match published version, typo fixed</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.15009">arXiv:2111.15009</a> <span> [<a href="https://arxiv.org/pdf/2111.15009">pdf</a>, <a href="https://arxiv.org/format/2111.15009">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/10.1016/j.dark.2021.100912">10.1016/j.dark.2021.100912 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Combined searches for dark matter in dwarf spheroidal galaxies observed with the MAGIC telescopes, including new data from Coma Berenices and Draco </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=Acciari%2C+V+A">V. A. Acciari</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</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=Bellizzi%2C+L">L. Bellizzi</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</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=B%C3%B6kenkamp%2C+H">H. B枚kenkamp</a> , et al. (169 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="2111.15009v1-abstract-short" style="display: inline;"> Milky Way dwarf spheroidal galaxies (dSphs) are among the best candidates to search for signals of dark matter annihilation with Imaging Atmospheric Cherenkov Telescopes, given their high mass-to-light ratios and the fact that they are free of astrophysical gamma-ray emitting sources. Since 2011, MAGIC has performed a multi-year observation program in search for Weakly Interacting Massive Particle… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.15009v1-abstract-full').style.display = 'inline'; document.getElementById('2111.15009v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.15009v1-abstract-full" style="display: none;"> Milky Way dwarf spheroidal galaxies (dSphs) are among the best candidates to search for signals of dark matter annihilation with Imaging Atmospheric Cherenkov Telescopes, given their high mass-to-light ratios and the fact that they are free of astrophysical gamma-ray emitting sources. Since 2011, MAGIC has performed a multi-year observation program in search for Weakly Interacting Massive Particles (WIMPs) in dSphs. Results on the observations of Segue 1 and Ursa Major II dSphs have already been published and include some of the most stringent upper limits (ULs) on the velocity-averaged cross-section $\langle 蟽_{\mathrm{ann}} v \rangle$ of WIMP annihilation from observations of dSphs. In this work, we report on the analyses of 52.1 h of data of Draco dSph and 49.5 h of Coma Berenices dSph observed with the MAGIC telescopes in 2018 and in 2019 respectively. No hint of a signal has been detected from either of these targets and new constraints on the $\langle 蟽_{\mathrm{ann}} v \rangle$ of WIMP candidates have been derived. In order to improve the sensitivity of the search and reduce the effect of the systematic uncertainties due to the $J$-factor estimates, we have combined the data of all dSphs observed with the MAGIC telescopes. Using 354.3 h of dSphs good quality data, 95 % CL ULs on $\langle 蟽_{\mathrm{ann}} v \rangle$ have been obtained for 9 annihilation channels. For most of the channels, these results reach values of the order of $10^{-24} $cm$^3$/s at ${\sim}1$ TeV and are the most stringent limits obtained with the MAGIC telescopes so far. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.15009v1-abstract-full').style.display = 'none'; document.getElementById('2111.15009v1-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> 29 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">17 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Physics of the Dark Universe, Volume 35, March 2022, 100912 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.12926">arXiv:2111.12926</a> <span> [<a href="https://arxiv.org/pdf/2111.12926">pdf</a>, <a href="https://arxiv.org/ps/2111.12926">ps</a>, <a href="https://arxiv.org/format/2111.12926">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/10.1093/mnras/stab3454">10.1093/mnras/stab3454 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multiwavelength study of the gravitationally lensed blazar QSO B0218+357 between 2016 and 2020 </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=Acciari%2C+V+A">V. A. Acciari</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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</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=Bellizzi%2C+L">L. Bellizzi</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</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> , et al. (186 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="2111.12926v1-abstract-short" style="display: inline;"> We report multiwavelength observations of the gravitationally lensed blazar QSO B0218+357 in 2016-2020. Optical, X-ray and GeV flares were detected. The contemporaneous MAGIC observations do not show significant very-high-energy (VHE, >= 100 GeV) gamma-ray emission. The lack of enhancement in radio emission measured by OVRO indicates the multi-zone nature of the emission from this object. We const… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.12926v1-abstract-full').style.display = 'inline'; document.getElementById('2111.12926v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.12926v1-abstract-full" style="display: none;"> We report multiwavelength observations of the gravitationally lensed blazar QSO B0218+357 in 2016-2020. Optical, X-ray and GeV flares were detected. The contemporaneous MAGIC observations do not show significant very-high-energy (VHE, >= 100 GeV) gamma-ray emission. The lack of enhancement in radio emission measured by OVRO indicates the multi-zone nature of the emission from this object. We constrain the VHE duty cycle of the source to be < 16 2014-like flares per year (95% confidence). For the first time for this source, a broadband low-state SED is constructed with a deep exposure up to the VHE range. A flux upper limit on the low-state VHE gamma-ray emission of an order of magnitude below that of the 2014 flare is determined. The X-ray data are used to fit the column density of (8.10 +- 0.93 stat ) x 10^21 cm^-2 of the dust in the lensing galaxy. VLBI observations show a clear radio core and jet components in both lensed images, yet no significant movement of the components is seen. The radio measurements are used to model the source-lens-observer geometry and determine the magnifications and time delays for both components. The quiescent emission is modeled with the high-energy bump explained as a combination of synchrotron-self-Compton and external Compton emission from a region located outside of the broad line region. The bulk of the low-energy emission is explained as originating from a tens-of-parsecs scale jet. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.12926v1-abstract-full').style.display = 'none'; document.getElementById('2111.12926v1-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 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">21 pages, 12 figures, 5 tables, accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.11373">arXiv:2108.11373</a> <span> [<a href="https://arxiv.org/pdf/2108.11373">pdf</a>, <a href="https://arxiv.org/format/2108.11373">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/ac20d7">10.3847/1538-4357/ac20d7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for Very High-Energy Emission from the millisecond pulsar PSR J0218+4232 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Acciari%2C+V+A">V. A. Acciari</a>, <a href="/search/astro-ph?searchtype=author&query=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=Engels%2C+A+A">A. Arbet Engels</a>, <a href="/search/astro-ph?searchtype=author&query=Artero%2C+M">M. Artero</a>, <a href="/search/astro-ph?searchtype=author&query=Asano%2C+K">K. Asano</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=Baquero%2C+A">A. Baquero</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=Batkovi%C4%87%2C+I">I. Batkovi膰</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=Bellizzi%2C+L">L. Bellizzi</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardos%2C+M">M. Bernardos</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Besenrieder%2C+J">J. Besenrieder</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Bigongiari%2C+C">C. Bigongiari</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=Bo%C5%A1njak%2C+%C5%BD">沤. Bo拧njak</a> , et al. (176 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="2108.11373v1-abstract-short" style="display: inline;"> PSR J0218+4232 is one of the most energetic millisecond pulsars known and has long been considered as one of the best candidates for very high-energy (VHE; >100 GeV) gamma-ray emission. Using 11.5 years of Fermi Large Area Telescope (LAT) data between 100 MeV and 870 GeV, and ~90 hours of MAGIC observations in the 20 GeV to 20 TeV range, we have searched for the highest energy gamma-ray emission f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.11373v1-abstract-full').style.display = 'inline'; document.getElementById('2108.11373v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.11373v1-abstract-full" style="display: none;"> PSR J0218+4232 is one of the most energetic millisecond pulsars known and has long been considered as one of the best candidates for very high-energy (VHE; >100 GeV) gamma-ray emission. Using 11.5 years of Fermi Large Area Telescope (LAT) data between 100 MeV and 870 GeV, and ~90 hours of MAGIC observations in the 20 GeV to 20 TeV range, we have searched for the highest energy gamma-ray emission from PSR J0218+4232. Based on the analysis of the LAT data, we find evidence for pulsed emission above 25 GeV, but see no evidence for emission above 100 GeV (VHE) with MAGIC. We present the results of searches for gamma-ray emission, along with theoretical modeling, to interpret the lack of VHE emission. We conclude that, based on the experimental observations and theoretical modeling, it will remain extremely challenging to detect VHE emission from PSR J0218+4232 with the current generation of Imaging Atmospheric Cherenkov Telescopes (IACTs), and maybe even with future ones, such as the Cherenkov Telescope Array (CTA). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.11373v1-abstract-full').style.display = 'none'; document.getElementById('2108.11373v1-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 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 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/2107.13278">arXiv:2107.13278</a> <span> [<a href="https://arxiv.org/pdf/2107.13278">pdf</a>, <a href="https://arxiv.org/format/2107.13278">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"> FR-0 jetted active galaxies: extending the zoo of candidate sites for UHECR acceleration </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Merten%2C+L">Lukas Merten</a>, <a href="/search/astro-ph?searchtype=author&query=Boughelilba%2C+M">Margot Boughelilba</a>, <a href="/search/astro-ph?searchtype=author&query=Reimer%2C+A">Anita Reimer</a>, <a href="/search/astro-ph?searchtype=author&query=Da+Vela%2C+P">Paolo Da Vela</a>, <a href="/search/astro-ph?searchtype=author&query=Vorobiov%2C+S">Serguei Vorobiov</a>, <a href="/search/astro-ph?searchtype=author&query=Tavecchio%2C+F">Fabrizio Tavecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">Giacomo Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Lundquist%2C+J+P">Jon Paul Lundquist</a>, <a href="/search/astro-ph?searchtype=author&query=Righi%2C+C">Chiara Righi</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="2107.13278v1-abstract-short" style="display: inline;"> Fanaroff-Riley (FR) 0 radio galaxies form a low-luminosity extension to the well-established ultra-high-energy cosmic-ray (UHECR) candidate accelerators FR-1 and FR-2 galaxies. Their much higher number density -- up to a factor five times more numerous than FR-1 with $z\leq 0.05$ -- makes them good candidate sources for an isotropic contribution to the observed UHECR flux. Here, the acceleration a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.13278v1-abstract-full').style.display = 'inline'; document.getElementById('2107.13278v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.13278v1-abstract-full" style="display: none;"> Fanaroff-Riley (FR) 0 radio galaxies form a low-luminosity extension to the well-established ultra-high-energy cosmic-ray (UHECR) candidate accelerators FR-1 and FR-2 galaxies. Their much higher number density -- up to a factor five times more numerous than FR-1 with $z\leq 0.05$ -- makes them good candidate sources for an isotropic contribution to the observed UHECR flux. Here, the acceleration and survival of UHECR in prevailing conditions of the FR-0 environment are discussed. First, an average spectral energy distribution (SED) is compiled based on the \textit{FR0CAT}. These photon fields, composed of a jet and a host galaxy component, form a minimal target photon field for the UHECR, which will suffer from electromagnetic pair production, photo-disintegration, photo-meson production losses, and synchrotron radiation. The two most promising acceleration scenarios based on Fermi-I order and gradual shear acceleration are discussed as well as different escape scenarios. When an efficient acceleration mechanism precedes gradual shear acceleration, e.g., Fermi-I or others, FR-0 galaxies are likely UHECR accelerators. Gradual shear acceleration requires a jet Lorentz factor of $螕>1.6$, to be faster than the corresponding escape. In less optimistic models, a contribution to the cosmic-ray flux between the knee and ankle is expected to be relatively independent of the realized turbulence and acceleration. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.13278v1-abstract-full').style.display = 'none'; document.getElementById('2107.13278v1-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, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">8 pages, 4 figures, 2 tables, ICRC 2021</span> </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous 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