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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Giacintucci%2C+S&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Giacintucci%2C+S&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Giacintucci%2C+S&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Giacintucci%2C+S&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.18075">arXiv:2409.18075</a> <span> [<a href="https://arxiv.org/pdf/2409.18075">pdf</a>, <a href="https://arxiv.org/format/2409.18075">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> </div> <p class="title is-5 mathjax"> The radio halo in PLCKESZ G171.94 $-$ 40.65: Beacon of merging activity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Santra%2C+R">Ramananda Santra</a>, <a href="/search/astro-ph?searchtype=author&query=Kale%2C+R">Ruta Kale</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Wik%2C+D+R">Daniel. R. Wik</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">Tiziana Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Dallacasa%2C+D">Daniele Dallacasa</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">Rossella Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">Gianfranco Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+D+C">Deepak Chandra Joshi</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="2409.18075v1-abstract-short" style="display: inline;"> We present the first multi-frequency analysis of the candidate ultra-steep spectrum radio halo in the galaxy cluster PLCKESZ G171.94$-$40.65, using the upgraded Giant Metrewave Radio telescope (uGMRT; 400 MHz), and Karl G. Jansky Very Large Array (JVLA; 1-2 GHz) observations. Our radio data have been complemented with archival \textit{Chandra} X-ray observations to provide a crucial insight into t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.18075v1-abstract-full').style.display = 'inline'; document.getElementById('2409.18075v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.18075v1-abstract-full" style="display: none;"> We present the first multi-frequency analysis of the candidate ultra-steep spectrum radio halo in the galaxy cluster PLCKESZ G171.94$-$40.65, using the upgraded Giant Metrewave Radio telescope (uGMRT; 400 MHz), and Karl G. Jansky Very Large Array (JVLA; 1-2 GHz) observations. Our radio data have been complemented with archival \textit{Chandra} X-ray observations to provide a crucial insight into the complex intracluster medium (ICM) physics, happening at large scales. We detect the radio halo emission to the extent of $\sim$ 1.5 Mpc at 400 MHz, significantly larger than previously reported, along with five tailed galaxies in the central region. We also report the discovery of an unknown diffuse source 'U', at the cluster periphery, with an extent of 300 kpc. Using the available observations, we have found that the radio spectrum of the halo is well-fitted with a single power law, having a spectral index of $-1.36 \pm 0.05$, indicating that it is not an ultra-steep spectrum radio halo. Our low-resolution (25$''$) resolved spectral map shows an overall uniform spectral index, with some patches of fluctuations. The X-ray and radio surface brightness are morphologically co-spatial, with a slight extension along the northwest-southeast direction, seen in both maps. The radio and X-ray surface brightness indicates strong positive correlations, with sub-linear correlation slopes ($\sim$ 0.71). Multiple tailed galaxies and the radio halo indicate a high dynamical activity at the cluster central region. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.18075v1-abstract-full').style.display = 'none'; document.getElementById('2409.18075v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 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">16 pages, 12 Figures, 6 Tables, Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.15440">arXiv:2409.15440</a> <span> [<a href="https://arxiv.org/pdf/2409.15440">pdf</a>, <a href="https://arxiv.org/format/2409.15440">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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/10.1051/0004-6361/202451766">10.1051/0004-6361/202451766 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Multi-Epoch Jet Outbursts in Abell 496: synchrotron ageing and buoyant X-ray cavities draped by warm gas filaments </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ubertosi%2C+F">Francesco Ubertosi</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T">Tracy Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Markevitch%2C+M">Maxim Markevitch</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">Tiziana Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Gitti%2C+M">Myriam Gitti</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="2409.15440v1-abstract-short" style="display: inline;"> The galaxy cluster Abell 496 has been extensively studied in the past for the clear sloshing motion of the hot gas on large scales, but the interplay between the central radio galaxy and the surrounding cluster atmosphere is mostly unexplored. We present a dedicated radio, X-ray, and optical study of Abell 496 aimed at investigating this connection. We use deep radio images obtained with the Giant… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.15440v1-abstract-full').style.display = 'inline'; document.getElementById('2409.15440v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.15440v1-abstract-full" style="display: none;"> The galaxy cluster Abell 496 has been extensively studied in the past for the clear sloshing motion of the hot gas on large scales, but the interplay between the central radio galaxy and the surrounding cluster atmosphere is mostly unexplored. We present a dedicated radio, X-ray, and optical study of Abell 496 aimed at investigating this connection. We use deep radio images obtained with the Giant Metrewave Radio Telescope at 150, 330 and 617 MHz, Very Large Array at 1.4 and 4.8 GHz, and VLA Low Band Ionosphere and Transient Experiment at 340 MHz, with angular resolutions ranging from 0.''5 to 25''. Additionally, we use archival Chandra and Very Large Telescope MUSE observations. The radio images reveal three distinct periods of jet activity: an ongoing episode on sub-kpc scales with an inverted radio spectrum; an older episode that produced lobes on scales $\sim$20 kpc which now have a steep spectral index ($伪= 2.0 \pm 0.1$); and an oldest episode that produced lobes on scales of $\sim$50 - 100 kpc with an ultra-steep spectrum ($伪= 2.7 \pm 0.2$). Archival Chandra X-ray observations show that the older and oldest episodes have excavated two generations of cavities in the hot gas of the cluster. The outermost X-ray cavity has a clear mushroom-head shape, likely caused by its buoyant rise in the cluster's potential. Cooling of the hot gas is ongoing in the innermost 20 kpc, where H$伪$-bright warm filaments are visible in VLT-MUSE data. The H$伪$-filaments are stretched towards the mushroom-head cavity, which may have stimulated ICM cooling in its wake. We conclude by commenting on the non-detection of a radio mini-halo in this vigorously sloshing, but low-mass, galaxy cluster. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.15440v1-abstract-full').style.display = 'none'; document.getElementById('2409.15440v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 September, 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 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 691, A294 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.07290">arXiv:2409.07290</a> <span> [<a href="https://arxiv.org/pdf/2409.07290">pdf</a>, <a href="https://arxiv.org/format/2409.07290">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> </div> <p class="title is-5 mathjax"> PSZ2 G282.28+49.94, a recently discovered analogue of the famous Bullet Cluster </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bartalucci%2C+I">I. Bartalucci</a>, <a href="/search/astro-ph?searchtype=author&query=Rossetti%2C+M">M. Rossetti</a>, <a href="/search/astro-ph?searchtype=author&query=Boschin%2C+W">W. Boschin</a>, <a href="/search/astro-ph?searchtype=author&query=Girardi%2C+M">M. Girardi</a>, <a href="/search/astro-ph?searchtype=author&query=Nonino%2C+M">M. Nonino</a>, <a href="/search/astro-ph?searchtype=author&query=Baraldi%2C+E">E. Baraldi</a>, <a href="/search/astro-ph?searchtype=author&query=Balboni%2C+M">M. Balboni</a>, <a href="/search/astro-ph?searchtype=author&query=Coe%2C+D">D. Coe</a>, <a href="/search/astro-ph?searchtype=author&query=De+Grandi%2C+S">S. De Grandi</a>, <a href="/search/astro-ph?searchtype=author&query=Gastaldello%2C+F">F. Gastaldello</a>, <a href="/search/astro-ph?searchtype=author&query=Ghizzardi%2C+S">S. Ghizzardi</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Grillo%2C+C">C. Grillo</a>, <a href="/search/astro-ph?searchtype=author&query=Harvey%2C+D">D. Harvey</a>, <a href="/search/astro-ph?searchtype=author&query=Lovisari%2C+L">L. Lovisari</a>, <a href="/search/astro-ph?searchtype=author&query=Molendi%2C+S">S. Molendi</a>, <a href="/search/astro-ph?searchtype=author&query=Resseguier%2C+T">T. Resseguier</a>, <a href="/search/astro-ph?searchtype=author&query=Riva%2C+G">G. Riva</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Zitrin%2C+A">A. Zitrin</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="2409.07290v1-abstract-short" style="display: inline;"> We present a detailed study of the gas and galaxy properties of the cluster PSZ2 G282.28+49.94 detected in the Planck all-sky survey. The intracluster medium (ICM) of this object at z=0.56 exhibits a cometary-like shape. Combining Chandra and TNG observations, we characterised the spatially resolved thermodynamical properties of the gas and the spatial and velocity distribution of 73 galaxy member… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.07290v1-abstract-full').style.display = 'inline'; document.getElementById('2409.07290v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.07290v1-abstract-full" style="display: none;"> We present a detailed study of the gas and galaxy properties of the cluster PSZ2 G282.28+49.94 detected in the Planck all-sky survey. The intracluster medium (ICM) of this object at z=0.56 exhibits a cometary-like shape. Combining Chandra and TNG observations, we characterised the spatially resolved thermodynamical properties of the gas and the spatial and velocity distribution of 73 galaxy members. The cluster structure is quite complex with an elongated core region containing the two brightest cluster galaxies and one dense group to the south-east. Since there is no velocity difference between the core and the south-east group, we suggest the presence of a merger along the plane of the sky. This structure is related to complex X-ray and radio features, and thus the merger has likely been caught during the post-merger phase. Comparing the distribution of the ICM and of member galaxies, we find a large offset of $\sim 350$ kpc between the position of the X-ray peak and the centre of a concentration of galaxies, preceding it in the likely direction of motion. This configuration is similar to the famous Bullet Cluster, leading us to dub PSZ2 G282.28+49.94 the "Planck bullet", and represents an ideal situation to provide astrophysical constraints to the self-interaction cross-section ($蟽/m$) of dark matter particles. These results illustrate the power of a multi-wavelength approach to probe the merging scenario of such complex and distant systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.07290v1-abstract-full').style.display = 'none'; document.getElementById('2409.07290v1-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 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 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/2409.06039">arXiv:2409.06039</a> <span> [<a href="https://arxiv.org/pdf/2409.06039">pdf</a>, <a href="https://arxiv.org/format/2409.06039">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> Probing the high frequency variability of NGC 5044: the key to AGN feedback </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schellenberger%2C+G">Gerrit Schellenberger</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=David%2C+L">Laurence David</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+J">Jan Vrtilek</a>, <a href="/search/astro-ph?searchtype=author&query=Romero%2C+C">Charles Romero</a>, <a href="/search/astro-ph?searchtype=author&query=Petitpas%2C+G">Glen Petitpas</a>, <a href="/search/astro-ph?searchtype=author&query=Forman%2C+W">William Forman</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Gurwell%2C+M">Mark Gurwell</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+C">Christine Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Rajpurohit%2C+K">Kamlesh Rajpurohit</a>, <a href="/search/astro-ph?searchtype=author&query=Ubertosi%2C+F">Francesco Ubertosi</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">Tiziana Venturi</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="2409.06039v2-abstract-short" style="display: inline;"> The active galactic nucleus (AGN) feeding and feedback process in the centers of galaxy clusters and groups is still not well understood. NGC 5044 is the ideal system in which to study AGN feedback. It hosts the largest known reservoir of cold gas in any cool-core galaxy group, and features several past epochs of AGN feedback imprinted as cavities in the X-ray bright intragroup medium (IGrM), as w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.06039v2-abstract-full').style.display = 'inline'; document.getElementById('2409.06039v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.06039v2-abstract-full" style="display: none;"> The active galactic nucleus (AGN) feeding and feedback process in the centers of galaxy clusters and groups is still not well understood. NGC 5044 is the ideal system in which to study AGN feedback. It hosts the largest known reservoir of cold gas in any cool-core galaxy group, and features several past epochs of AGN feedback imprinted as cavities in the X-ray bright intragroup medium (IGrM), as well as parsec scale jets. We present Submillimeter Array (SMA), Karl G. Jansky Very Large Array (VLA), James Clerk Maxwell Telescope (JCMT), and Atacama Large Millimeter/submillimeter Array (ALMA) high frequency observations of NGC 5044 to assess the time variability of the mmwaveband emission from the accretion disk, and quantify the Spectral Energy Distribution (SED) from the radio to sub-millimeter band. The SED is well described by advection dominated accretion flow (ADAF) model and self-absorbed jet emission from an aging plasma with tau = 1kyr. We find a characteristic variability timescale of 150 days, which constrains the ADAF emission region to about 0.1pc, and the magnetic field to 4.7mG in the jets and and 870G in the accretion disk. A longer monitoring/sampling will allow to understand if the underlying process is truly periodic in nature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.06039v2-abstract-full').style.display = 'none'; document.getElementById('2409.06039v2-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">v1</span> submitted 9 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">17 pages, 7 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.15197">arXiv:2408.15197</a> <span> [<a href="https://arxiv.org/pdf/2408.15197">pdf</a>, <a href="https://arxiv.org/format/2408.15197">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> </div> <p class="title is-5 mathjax"> A Deep Dive into the NGC 741 Galaxy Group: Insights into a Spectacular Head-Tail Radio Galaxy from VLA, MeerKAT, uGMRT and LOFAR </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Rajpurohit%2C+K">K. Rajpurohit</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">E. O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Schellenberger%2C+G">G. Schellenberger</a>, <a href="/search/astro-ph?searchtype=author&query=Brienza%2C+M">M. Brienza</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+J+M">J. M. Vrtilek</a>, <a href="/search/astro-ph?searchtype=author&query=Forman%2C+W">W. Forman</a>, <a href="/search/astro-ph?searchtype=author&query=David%2C+L+P">L. P. David</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T">T. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Botteon%2C+A">A. Botteon</a>, <a href="/search/astro-ph?searchtype=author&query=Vazza%2C+F">F. Vazza</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+C">C. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Br%C3%BCggen%2C+M">M. Br眉ggen</a>, <a href="/search/astro-ph?searchtype=author&query=Shimwell%2C+T+W">T. W. Shimwell</a>, <a href="/search/astro-ph?searchtype=author&query=Drabent%2C+A">A. Drabent</a>, <a href="/search/astro-ph?searchtype=author&query=Loi%2C+F">F. Loi</a>, <a href="/search/astro-ph?searchtype=author&query=Loubser%2C+S+I">S. I. Loubser</a>, <a href="/search/astro-ph?searchtype=author&query=Kolokythas%2C+K">K. Kolokythas</a>, <a href="/search/astro-ph?searchtype=author&query=Babyk%2C+I">I. Babyk</a>, <a href="/search/astro-ph?searchtype=author&query=R%C3%B6ttgering%2C+H+J+A">H. J. A. R枚ttgering</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="2408.15197v1-abstract-short" style="display: inline;"> We present deep, wideband multifrequency radio observations (144 MHz$-$8 GHz) of the remarkable galaxy group NGC 741, which yield crucial insights into the interaction between the infalling head-tail radio galaxy (NGC 742) and the main group. Our new data provide an unprecedentedly detailed view of the NGC 741-742 system, including the shock cone, disrupted jets from NGC 742, the long ($\sim$ 255… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.15197v1-abstract-full').style.display = 'inline'; document.getElementById('2408.15197v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.15197v1-abstract-full" style="display: none;"> We present deep, wideband multifrequency radio observations (144 MHz$-$8 GHz) of the remarkable galaxy group NGC 741, which yield crucial insights into the interaction between the infalling head-tail radio galaxy (NGC 742) and the main group. Our new data provide an unprecedentedly detailed view of the NGC 741-742 system, including the shock cone, disrupted jets from NGC 742, the long ($\sim$ 255 kpc) braided southern radio tail, and eastern lobe-like structure, and reveal, for the first time, complex radio filaments throughout the tail and lobe, and a likely vortex ring behind the shock cone. The cone traces the bow shock caused by the supersonic ($\mathcal{M}\sim2$) interaction between the head-tail radio galaxy NGC 742 and the intragroup medium (IGrM) while the ring may have been formed by interaction between the NGC 742 shock and a previously existing lobe associated with NGC 741. This interaction plausibly compressed and re-accelerated the radio plasma. We estimate that shock-heating by NGC 742 has likely injected $\sim$2-5$\times$10$^{57}$ erg of thermal energy into the central 10 kpc cooling region of the IGrM, potentially affecting the cooling and feedback cycle of NGC 741. A comparison with Chandra X-ray images shows that some of the previously detected thermal filaments align with radio edges, suggesting compression of the IGrM as the relativistic plasma of the NGC 742 tail interacts with the surrounding medium. Our results highlight that multi-frequency observations are key to disentangling the complex, intertwined origins of the variety of radio features seen in the galaxy group NGC 741, and the need for simulations to reproduce all the detected features. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.15197v1-abstract-full').style.display = 'none'; document.getElementById('2408.15197v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">26 pages, 15 figures, submitted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.14142">arXiv:2408.14142</a> <span> [<a href="https://arxiv.org/pdf/2408.14142">pdf</a>, <a href="https://arxiv.org/format/2408.14142">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Cosmic dance in the Shapley Concentration Core II. The uGMRT-MeerKAT view of filaments in the brightest cluster galaxies and tailed radio galaxies in the A3528 cluster complex </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Di+Gennaro%2C+G">G. Di Gennaro</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Br%C3%BCggen%2C+M">M. Br眉ggen</a>, <a href="/search/astro-ph?searchtype=author&query=Bulbul%2C+E">E. Bulbul</a>, <a href="/search/astro-ph?searchtype=author&query=Sanders%2C+J">J. Sanders</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+A">A. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+X">X. Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Trehaeven%2C+K">K. Trehaeven</a>, <a href="/search/astro-ph?searchtype=author&query=Dallacasa%2C+D">D. Dallacasa</a>, <a href="/search/astro-ph?searchtype=author&query=Merluzzi%2C+P">P. Merluzzi</a>, <a href="/search/astro-ph?searchtype=author&query=Pasini%2C+T">T. Pasini</a>, <a href="/search/astro-ph?searchtype=author&query=Bardelli%2C+S">S. Bardelli</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardi%2C+G">G. Bernardi</a>, <a href="/search/astro-ph?searchtype=author&query=Smirnov%2C+O">O. Smirnov</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="2408.14142v1-abstract-short" style="display: inline;"> Superclusters are the largest-scale environments where a number of galaxy clusters interact with each other through minor/major mergers and grow via accretion along cosmic filaments. We focus on the A3528 complex in the core of the Shapley Supercluster. This system includes three clusters, A3528 (composed itself by two sub-clusters, namely A3528N and A3528S), A3532 and A3530, and presents a mildly… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14142v1-abstract-full').style.display = 'inline'; document.getElementById('2408.14142v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.14142v1-abstract-full" style="display: none;"> Superclusters are the largest-scale environments where a number of galaxy clusters interact with each other through minor/major mergers and grow via accretion along cosmic filaments. We focus on the A3528 complex in the core of the Shapley Supercluster. This system includes three clusters, A3528 (composed itself by two sub-clusters, namely A3528N and A3528S), A3532 and A3530, and presents a mildly active dynamical state. We study how minor mergers affect the evolution of radio galaxies and whether they are able to re-accelerate relativistic electrons in the ICM. We used observations from the uGMRT (Band 3, 4 and 5) and MeerKAT (L-band) telescopes to obtain images and spectral index maps over a wide frequency band and spatial resolutions. We compare these data with those from the SRG/eROSITA X-ray telescope. We detect faint diffuse radio emission associated with the radio galaxies. The BCGs in A3528S and A3532 show filaments of diffuse radio emission which extend for $\sim200-400$ kpc out of the radio galaxy. The spectral index of these filaments is extremely steep and almost constant ($伪\sim -2, -2.5$). Contrary to the radio tails in A3528N, the spectral properties of these radio filaments are not consistent with standard models of plasma ageing. We also detect roundish diffuse radio emission around the BCG in A3528S which could be classified as a radio mini-halo. The radio tail in this cluster appears longer that in earlier detections, being $\sim300$ kpc long at all frequencies. We linked the presence of extended radio emission in the form of filaments and threads in the A3528 complex with the effect of minor mergers. This is reinforced by the increasing X-ray fluctuations in correspondence with the radio extended emission in A3528S. Despite the less energy involved, our findings support the hypothesis that these events can re-energise plasma originating from radio galaxies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14142v1-abstract-full').style.display = 'none'; document.getElementById('2408.14142v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">28 pages, 23 figures and 5 tables; accepted for publication in Astronomy & 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/2408.07178">arXiv:2408.07178</a> <span> [<a href="https://arxiv.org/pdf/2408.07178">pdf</a>, <a href="https://arxiv.org/format/2408.07178">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> Probing cluster magnetism with embedded and background radio sources in Planck clusters </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Osinga%2C+E">Erik Osinga</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R+J">Reinout J. van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Rudnick%2C+L">Lawrence Rudnick</a>, <a href="/search/astro-ph?searchtype=author&query=Andrade-Santos%2C+F">Felipe Andrade-Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Bonafede%2C+A">Annalisa Bonafede</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T">Tracy Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Duncan%2C+K">Kenda Duncan</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=R%C3%B6ttgering%2C+H+J+A">Huub J. A. R枚ttgering</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="2408.07178v1-abstract-short" style="display: inline;"> Magnetic fields remain an enigmatic part of the content of galaxy clusters. Faraday rotation and depolarisation of extragalactic radio sources are useful probes, but the limited availability of polarised radio sources necessitates stacking clusters to study average magnetic field profiles and correlation scales. We recently presented a VLA survey of the 124 most massive Planck clusters at low reds… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.07178v1-abstract-full').style.display = 'inline'; document.getElementById('2408.07178v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.07178v1-abstract-full" style="display: none;"> Magnetic fields remain an enigmatic part of the content of galaxy clusters. Faraday rotation and depolarisation of extragalactic radio sources are useful probes, but the limited availability of polarised radio sources necessitates stacking clusters to study average magnetic field profiles and correlation scales. We recently presented a VLA survey of the 124 most massive Planck clusters at low redshift ($z<0.35$), where a clear depolarisation trend with the cluster impact parameter was found. In this study, we combine the depolarisation information with the observed rotation measure (RM) and present an investigation into the average magnetic field properties of the sample, using both background sources and sources embedded in clusters. We observe a significant increase in the RM scatter, $蟽_\mathrm{RRM}$, closer to the cluster centres. Averaging all 124 clusters, we find a scatter within $R_\mathrm{500}$ of $蟽_\mathrm{RRM}=209\pm37$ rad m$^{-2}$, with background sources and cluster members showing similar values ($200\pm33$ and $219\pm66$ rad m$^{-2}$, respectively). In the simple assumption of a uniform magnetic field with a single fluctuation scale $螞_c$, this translates to an average magnetic field strength of $2\,(螞_c/10\mathrm{kpc})^{-0.5}\, 渭$G. The profile of $蟽_\mathrm{RRM}$ as a function of projected radius is inconsistent with a model that has a simple scaling $B \propto n_e^畏$, with an observed deficit near the centre of clusters possibly caused by the fact that the highest RM sources near the centre of clusters are depolarised. In a full forward model, we find that the magnetic field power spectrum agrees with the Kolmogorov value, but that none of the Gaussian random field models can fully explain the observed relatively flat profiles. This implies that more sophisticated models of cluster magnetic fields in a cosmological context are needed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.07178v1-abstract-full').style.display = 'none'; document.getElementById('2408.07178v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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 on 2024-08-13</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.21628">arXiv:2407.21628</a> <span> [<a href="https://arxiv.org/pdf/2407.21628">pdf</a>, <a href="https://arxiv.org/ps/2407.21628">ps</a>, <a href="https://arxiv.org/format/2407.21628">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Ram-pressure stripped radio tails detected in the dynamically active environment of the Shapley Supercluster </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Merluzzi%2C+P">P. Merluzzi</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Busarello%2C+G">G. Busarello</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gennaro%2C+G">G. Di Gennaro</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Casasola%2C+V">V. Casasola</a>, <a href="/search/astro-ph?searchtype=author&query=Krajnovic%2C+D">D. Krajnovic</a>, <a href="/search/astro-ph?searchtype=author&query=Vernstrom%2C+T">T. Vernstrom</a>, <a href="/search/astro-ph?searchtype=author&query=Carretti%2C+E">E. Carretti</a>, <a href="/search/astro-ph?searchtype=author&query=Smirnov%2C+O">O. Smirnov</a>, <a href="/search/astro-ph?searchtype=author&query=Trehaeven%2C+K">K. Trehaeven</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+C+S">C. S. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Chesters%2C+J">J. Chesters</a>, <a href="/search/astro-ph?searchtype=author&query=Heald%2C+G">G. Heald</a>, <a href="/search/astro-ph?searchtype=author&query=Hopkins%2C+A+M">A. M. Hopkins</a>, <a href="/search/astro-ph?searchtype=author&query=Koribalski%2C+B">B. Koribalski</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="2407.21628v1-abstract-short" style="display: inline;"> We study the radio continuum emission of four galaxies experiencing ram-pressure stripping in four clusters of the Shapley supercluster at redshift z~0.05. Multi-band (235-1367 MHz) radio data, complemented by integral-field spectroscopy, allow us to detect and analyse in detail the non-thermal component both in the galaxy discs and the radio continuum tails. Three galaxies present radio continuum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.21628v1-abstract-full').style.display = 'inline'; document.getElementById('2407.21628v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.21628v1-abstract-full" style="display: none;"> We study the radio continuum emission of four galaxies experiencing ram-pressure stripping in four clusters of the Shapley supercluster at redshift z~0.05. Multi-band (235-1367 MHz) radio data, complemented by integral-field spectroscopy, allow us to detect and analyse in detail the non-thermal component both in the galaxy discs and the radio continuum tails. Three galaxies present radio continuum tails which are tens of kiloparsecs long. By deriving the radio spectral index in the inner and outer tails and comparing our findings with the distribution of the extraplanar ionised gas and the results of N-body/hydrodynamical simulations, we demonstrate that these tails are caused by the ram pressure which, together with the ionised gas, sweeps the magnetic field from the galaxy discs. We suggest that the radio continuum emission in these tails can be differently powered by (i) in situ star formation; (ii) relativistic electrons stripped from the disc; (iii) shock excitation or a combination of them. All the ram-pressure stripped galaxies are found in environments where cluster-cluster interactions occurred and/or are ongoing thus strongly supporting the thesis that cluster and group collisions and mergers may locally increase the ram pressure and trigger hydrodynamical interactions between the intracluster medium and the interstellar medium of galaxies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.21628v1-abstract-full').style.display = 'none'; document.getElementById('2407.21628v1-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, 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">18 pages, 14 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/2407.12266">arXiv:2407.12266</a> <span> [<a href="https://arxiv.org/pdf/2407.12266">pdf</a>, <a href="https://arxiv.org/format/2407.12266">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/s41550-024-02277-w">10.1038/s41550-024-02277-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An emission state switching radio transient with a 54 minute period </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Caleb%2C+M">M. Caleb</a>, <a href="/search/astro-ph?searchtype=author&query=Lenc%2C+E">E. Lenc</a>, <a href="/search/astro-ph?searchtype=author&query=Kaplan%2C+D+L">D. L. Kaplan</a>, <a href="/search/astro-ph?searchtype=author&query=Murphy%2C+T">T. Murphy</a>, <a href="/search/astro-ph?searchtype=author&query=Men%2C+Y+P">Y. P. Men</a>, <a href="/search/astro-ph?searchtype=author&query=Shannon%2C+R+M">R. M. Shannon</a>, <a href="/search/astro-ph?searchtype=author&query=Ferrario%2C+L">L. Ferrario</a>, <a href="/search/astro-ph?searchtype=author&query=Rajwade%2C+K+M">K. M. Rajwade</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T+E">T. E. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Hurley-Walker%2C+N">N. Hurley-Walker</a>, <a href="/search/astro-ph?searchtype=author&query=Hyman%2C+S+D">S. D. Hyman</a>, <a href="/search/astro-ph?searchtype=author&query=Lower%2C+M+E">M. E. Lower</a>, <a href="/search/astro-ph?searchtype=author&query=McSweeney%2C+S">Sam McSweeney</a>, <a href="/search/astro-ph?searchtype=author&query=Ravi%2C+V">V. Ravi</a>, <a href="/search/astro-ph?searchtype=author&query=Barr%2C+E+D">E. D. Barr</a>, <a href="/search/astro-ph?searchtype=author&query=Buchner%2C+S">S. Buchner</a>, <a href="/search/astro-ph?searchtype=author&query=Flynn%2C+C+M+L">C. M. L. Flynn</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">J. W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Pritchard%2C+J">J. Pritchard</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</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="2407.12266v1-abstract-short" style="display: inline;"> Long-period radio transients are an emerging class of extreme astrophysical events of which only three are known. These objects emit highly polarised, coherent pulses of typically a few tens of seconds duration and minutes to hour-long periods. While magnetic white dwarfs and magnetars, either isolated or in binary systems, have been invoked to explain these objects, a consensus has not emerged. H… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.12266v1-abstract-full').style.display = 'inline'; document.getElementById('2407.12266v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.12266v1-abstract-full" style="display: none;"> Long-period radio transients are an emerging class of extreme astrophysical events of which only three are known. These objects emit highly polarised, coherent pulses of typically a few tens of seconds duration and minutes to hour-long periods. While magnetic white dwarfs and magnetars, either isolated or in binary systems, have been invoked to explain these objects, a consensus has not emerged. Here we report on the discovery of ASKAP J193505.1+214841.0 (henceforth ASKAPJ1935+2148) with a period of 53.8 minutes exhibiting three distinct emission states - a bright pulse state with highly linearly polarised pulses with widths of 10-50 seconds; a weak pulse state which is about 26 times fainter than the bright state with highly circularly polarised pulses of widths of approximately 370 milliseconds; and a quiescent or quenched state with no pulses. The first two states have been observed to progressively evolve over the course of 8 months with the quenched state interspersed between them suggesting physical changes in the region producing the emission. A constraint on the radius of the source for the observed period rules out a magnetic white dwarf origin. Unlike other long-period sources, ASKAPJ1935+2148 is the first to exhibit drastic variations in emission modes reminiscent of neutron stars. However, its radio properties challenge our current understanding of neutron star emission and evolution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.12266v1-abstract-full').style.display = 'none'; document.getElementById('2407.12266v1-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 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">Published in Nature Astronomy</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.18983">arXiv:2406.18983</a> <span> [<a href="https://arxiv.org/pdf/2406.18983">pdf</a>, <a href="https://arxiv.org/format/2406.18983">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202451293">10.1051/0004-6361/202451293 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The prototypical major cluster merger Abell 754. I. Calibration of MeerKAT data and radio/X-ray spectral mapping of the cluster </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Botteon%2C+A">A. Botteon</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R+J">R. J. van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Eckert%2C+D">D. Eckert</a>, <a href="/search/astro-ph?searchtype=author&query=Gastaldello%2C+F">F. Gastaldello</a>, <a href="/search/astro-ph?searchtype=author&query=Markevitch%2C+M">M. Markevitch</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">G. Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Kale%2C+R">R. Kale</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</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="2406.18983v2-abstract-short" style="display: inline;"> Abell 754 is a rich galaxy cluster at $z=0.0543$ and is considered the prototype of a major cluster merger. Like many dynamically unrelaxed systems, it hosts diffuse radio emission on Mpc-scales. Extended synchrotron sources in the intra-cluster medium (ICM) are commonly interpreted as evidence that a fraction of the gravitational energy released during cluster mergers is dissipated into nontherma… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.18983v2-abstract-full').style.display = 'inline'; document.getElementById('2406.18983v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.18983v2-abstract-full" style="display: none;"> Abell 754 is a rich galaxy cluster at $z=0.0543$ and is considered the prototype of a major cluster merger. Like many dynamically unrelaxed systems, it hosts diffuse radio emission on Mpc-scales. Extended synchrotron sources in the intra-cluster medium (ICM) are commonly interpreted as evidence that a fraction of the gravitational energy released during cluster mergers is dissipated into nonthermal components. Here, we use new MeerKAT UHF- and L-band observations to study nonthermal phenomena in Abell 754. These data are complemented with archival XMM-Newton observations to investigate the resolved spectral properties of both the radio and X-ray cluster emission.For the first time, we employed the pipeline originally developed to calibrate LOFAR data to MeerKAT observations. This allowed us to perform a direction-dependent calibration and obtain highly sensitive radio images in UHF- and L-bands which capture the extended emission with unprecedented detail. By using a large XMM-Newton mosaic, we produced thermodynamic maps of the ICM. Our analysis reveals that the radio halo in the cluster center is bounded by the well-known shock in the eastern direction. Furthermore, in the southwest periphery, we discover an extended radio source that we classify as a radio relic which is possibly tracing a shock driven by the squeezed gas compressed by the merger, outflowing in perpendicular directions. The low-luminosity of this relic appears compatible with direct acceleration of thermal pool electrons. We interpret the observed radio and X-ray features in the context of a major cluster merger with a nonzero impact parameter. Abell 754 is a remarkable galaxy cluster showcasing exceptional features associated with the ongoing merger event. The high quality of the new MeerKAT data motivates further work on this system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.18983v2-abstract-full').style.display = 'none'; document.getElementById('2406.18983v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 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">18 pages, 14 figures, 3 tables (excluding Appendix); Updated to match the accepted version 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 690, A222 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.11694">arXiv:2312.11694</a> <span> [<a href="https://arxiv.org/pdf/2312.11694">pdf</a>, <a href="https://arxiv.org/format/2312.11694">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 VLITE Search for Millisecond Pulsars in Globular Clusters: Discovery of a Pulsar in GLIMPSE-C01 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=McCarver%2C+A+V">Amaris V. McCarver</a>, <a href="/search/astro-ph?searchtype=author&query=Maccarone%2C+T+J">Thomas J. Maccarone</a>, <a href="/search/astro-ph?searchtype=author&query=Ransom%2C+S+M">Scott M. Ransom</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T+E">Tracy E. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Peters%2C+W+M">Wendy M. Peters</a>, <a href="/search/astro-ph?searchtype=author&query=Polisensky%2C+E">Emil Polisensky</a>, <a href="/search/astro-ph?searchtype=author&query=Nyland%2C+K">Kristina Nyland</a>, <a href="/search/astro-ph?searchtype=author&query=Gautam%2C+T">Tasha Gautam</a>, <a href="/search/astro-ph?searchtype=author&query=Freire%2C+P+C+C">Paulo C. C. Freire</a>, <a href="/search/astro-ph?searchtype=author&query=Rangelov%2C+B">Blagoy Rangelov</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="2312.11694v1-abstract-short" style="display: inline;"> We present results from a search for pulsars in globular clusters, including the discovery of a new millisecond pulsar in the stellar cluster GLIMPSE-C01. We searched for low frequency radio sources within 97 globular clusters using images from the VLA Low-band Ionosphere and Transient Experiment (VLITE) and epochs 1 and 2 of the VLITE Commensal Sky Survey (VCSS). We discovered 10 sources in our s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.11694v1-abstract-full').style.display = 'inline'; document.getElementById('2312.11694v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.11694v1-abstract-full" style="display: none;"> We present results from a search for pulsars in globular clusters, including the discovery of a new millisecond pulsar in the stellar cluster GLIMPSE-C01. We searched for low frequency radio sources within 97 globular clusters using images from the VLA Low-band Ionosphere and Transient Experiment (VLITE) and epochs 1 and 2 of the VLITE Commensal Sky Survey (VCSS). We discovered 10 sources in our search area, four more than expected from extragalactic source counts at our sensitivity limits. The strongest pulsar candidate was a point source found in GLIMPSE-C01 with a spectral index ~ -2.6, and we present additional measurements at 0.675 and 1.25 GHz from the GMRT and 1.52 GHz from the VLA which confirm the spectral index. Using archival Green Bank Telescope S-band data from 2005, we detect a binary pulsar with a spin period of 19.78 ms within the cluster. Although we cannot confirm that this pulsar is at the same position as the steep spectrum source using the existing data, the pulse flux is consistent with the predicted flux density from other frequencies, making it a probable match. The source also shows strong X-ray emission, indicative of a higher magnetic field than most millisecond pulsars, suggesting that its recycling was interrupted. We demonstrate that low frequency searches for steep spectrum sources are an effective way to identify pulsar candidates, particularly on sightlines with high dispersion. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.11694v1-abstract-full').style.display = 'none'; document.getElementById('2312.11694v1-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> 18 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">19 pages, 4 figures, submitted to 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/2312.02824">arXiv:2312.02824</a> <span> [<a href="https://arxiv.org/pdf/2312.02824">pdf</a>, <a href="https://arxiv.org/format/2312.02824">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> <p class="title is-5 mathjax"> Are radio minihalos confined by cold fronts in galaxy clusters? Minihalos and large-scale sloshing in A3444 and MS 1455.0+2232 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">Tiziana Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Markevitch%2C+M">Maxim Markevitch</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">Gianfranco Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T">Tracy Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Kale%2C+R">Ruta Kale</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="2312.02824v1-abstract-short" style="display: inline;"> We present radio and X-ray studies of A3444 and MS1455.0+2232, two galaxy clusters with radio minihalos in their cool cores. A3444 is imaged using the Giant Metrewave Radio Telescope (GMRT) at 333, 607 and 1300 MHz and the Very Large Array at 1435 MHz. Most of the minihalo is contained within r<120 kpc, but a fainter extension, stretching out to 380 kpc South-West of the center, is detected at 607… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.02824v1-abstract-full').style.display = 'inline'; document.getElementById('2312.02824v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.02824v1-abstract-full" style="display: none;"> We present radio and X-ray studies of A3444 and MS1455.0+2232, two galaxy clusters with radio minihalos in their cool cores. A3444 is imaged using the Giant Metrewave Radio Telescope (GMRT) at 333, 607 and 1300 MHz and the Very Large Array at 1435 MHz. Most of the minihalo is contained within r<120 kpc, but a fainter extension, stretching out to 380 kpc South-West of the center, is detected at 607 MHz. Using Chandra, we detect four X-ray sloshing cold fronts: three in the cool core at r=60, 120 and 230 kpc, and a fourth one at r=400 kpc - in the region of the southwestern radio extension - suggesting that the intracluster medium (ICM) is sloshing on a cluster-wide scale. The radio emission is contained within the envelope defined by these fronts. We also analyzed archival 383 MHz GMRT and Chandra observations of MS1455.0+2232, which exhibits a known minihalo with its bright part delineated by cold fronts inside the cool core, but with a faint extension beyond the core. Similarly to A3444, we find a cold front at r~425 kpc, containing the radio emission. Thus the entire diffuse radio emission seen in these clusters appears to be related to large-scale sloshing of the ICM. The radio spectrum of the A3444 minihalo is a power law with a steep index $伪=1.0\pm0.1$. The spectrum steepens with increasing distance from the center, as expected if the minihalo originates from re-acceleration of relativistic particles by the sloshing-induced turbulence in the ICM. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.02824v1-abstract-full').style.display = 'none'; document.getElementById('2312.02824v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 December, 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">29 pages, 15 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.02283">arXiv:2312.02283</a> <span> [<a href="https://arxiv.org/pdf/2312.02283">pdf</a>, <a href="https://arxiv.org/format/2312.02283">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Jet reorientation in central galaxies of clusters and groups: insights from VLBA and Chandra data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ubertosi%2C+F">Francesco Ubertosi</a>, <a href="/search/astro-ph?searchtype=author&query=Schellenberger%2C+G">Gerrit Schellenberger</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+J">Jan Vrtilek</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=David%2C+L+P">Laurence P. David</a>, <a href="/search/astro-ph?searchtype=author&query=Forman%2C+W">William Forman</a>, <a href="/search/astro-ph?searchtype=author&query=Gitti%2C+M">Myriam Gitti</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">Tiziana Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+C">Christine Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Brighenti%2C+F">Fabrizio Brighenti</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="2312.02283v1-abstract-short" style="display: inline;"> Recent observations of galaxy clusters and groups with misalignments between their central AGN jets and X-ray cavities, or with multiple misaligned cavities, have raised concerns about the jet - bubble connection in cooling cores, and the processes responsible for jet realignment. To investigate the frequency and causes of such misalignments, we construct a sample of 16 cool core galaxy clusters a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.02283v1-abstract-full').style.display = 'inline'; document.getElementById('2312.02283v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.02283v1-abstract-full" style="display: none;"> Recent observations of galaxy clusters and groups with misalignments between their central AGN jets and X-ray cavities, or with multiple misaligned cavities, have raised concerns about the jet - bubble connection in cooling cores, and the processes responsible for jet realignment. To investigate the frequency and causes of such misalignments, we construct a sample of 16 cool core galaxy clusters and groups. Using VLBA radio data we measure the parsec-scale position angle of the jets, and compare it with the position angle of the X-ray cavities detected in Chandra data. Using the overall sample and selected subsets, we consistently find that there is a 30% - 38% chance to find a misalignment larger than $螖唯= 45^{\circ}$ when observing a cluster/group with a detected jet and at least one cavity. We determine that projection may account for an apparently large $螖唯$ only in a fraction of objects ($\sim$35%), and given that gas dynamical disturbances (as sloshing) are found in both aligned and misaligned systems, we exclude environmental perturbation as the main driver of cavity - jet misalignment. Moreover, we find that large misalignments (up to $\sim90^{\circ}$) are favored over smaller ones ($45^{\circ}\leq螖唯\leq70^{\circ}$), and that the change in jet direction can occur on timescales between one and a few tens of Myr. We conclude that misalignments are more likely related to actual reorientation of the jet axis, and we discuss several engine-based mechanisms that may cause these dramatic changes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.02283v1-abstract-full').style.display = 'none'; document.getElementById('2312.02283v1-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 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 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/2311.09717">arXiv:2311.09717</a> <span> [<a href="https://arxiv.org/pdf/2311.09717">pdf</a>, <a href="https://arxiv.org/format/2311.09717">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> </div> <p class="title is-5 mathjax"> A Deep uGMRT view of the ultra steep spectrum radio halo in Abell 521 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Santra%2C+R">Ramananda Santra</a>, <a href="/search/astro-ph?searchtype=author&query=Kale%2C+R">Ruta Kale</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Markevitch%2C+M">Maxim Markevitch</a>, <a href="/search/astro-ph?searchtype=author&query=Luca%2C+F+D">Federico De. Luca</a>, <a href="/search/astro-ph?searchtype=author&query=Bourdin%2C+H">Herve Bourdin</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">Tiziana Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Dallacasa%2C+D">Daniele Dallacasa</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">Rossella Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">Gianfranco Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Buch%2C+K">Kaushal Buch</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="2311.09717v1-abstract-short" style="display: inline;"> We present the first detailed analysis of the ultra-steep spectrum radio halo in the merging galaxy cluster Abell 521, based on upgraded Giant Metrewave Radio telescope (uGMRT) observations. The combination of radio observations (300-850 MHz) and archival X-ray data provide a new window into the complex physics occurring in this system. When compared to all previous analyses, our sensitive radio i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.09717v1-abstract-full').style.display = 'inline'; document.getElementById('2311.09717v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.09717v1-abstract-full" style="display: none;"> We present the first detailed analysis of the ultra-steep spectrum radio halo in the merging galaxy cluster Abell 521, based on upgraded Giant Metrewave Radio telescope (uGMRT) observations. The combination of radio observations (300-850 MHz) and archival X-ray data provide a new window into the complex physics occurring in this system. When compared to all previous analyses, our sensitive radio images detected the centrally located radio halo emission to a greater extent of $\sim$ 1.3 Mpc. A faint extension of the southeastern radio relic has been discovered. We detected another relic, recently discovered by MeerKAT, and coincident with a possible shock front in the X-rays, at the northwest position of the center. We find that the integrated spectrum of the radio halo is well-fitted with a spectral index of $-1.86 \pm 0.12$. A spatially resolved spectral index map revealed the spectral index fluctuations, as well as an outward radial steepening of the average spectral index. The radio and X-ray surface brightness are well correlated for the entire and different sub-parts of the halo, with sub-linear correlation slopes (0.50$-$0.65). We also found a mild anti-correlation between the spectral index and X-ray surface brightness. Newly detected extensions of the SE relic and the counter relic are consistent with the merger in the plane of the sky. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.09717v1-abstract-full').style.display = 'none'; document.getElementById('2311.09717v1-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 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">31 pages (total), 35 figures, 7 tables, 2 appendix (12 figures, 2 tables). Accepted for publication in Astrophysical Journal (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/2303.08833">arXiv:2303.08833</a> <span> [<a href="https://arxiv.org/pdf/2303.08833">pdf</a>, <a href="https://arxiv.org/format/2303.08833">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/acc52e">10.3847/1538-4357/acc52e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Feedback in the merging galaxy group NGC6338 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schellenberger%2C+G">Gerrit Schellenberger</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+J">Jan Vrtilek</a>, <a href="/search/astro-ph?searchtype=author&query=David%2C+L+P">Laurence P. David</a>, <a href="/search/astro-ph?searchtype=author&query=Combes%2C+F">Francoise Combes</a>, <a href="/search/astro-ph?searchtype=author&query=B%C3%AErzan%2C+L">Laura B卯rzan</a>, <a href="/search/astro-ph?searchtype=author&query=Pan%2C+H">Hsi-An Pan</a>, <a href="/search/astro-ph?searchtype=author&query=Lin%2C+L">Lihwai Lin</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="2303.08833v1-abstract-short" style="display: inline;"> The galaxy group NGC6338 is one of the most violent group-group mergers known to date. While the central dominant galaxies rush at each other at 1400km/s along the line of sight, with dramatic gas heating and shock fronts detected, the central gas in the BCGs remains cool. There are also indications of feedback from active galactic nuclei (AGNs), and neither subcluster core has been disrupted. Wit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.08833v1-abstract-full').style.display = 'inline'; document.getElementById('2303.08833v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.08833v1-abstract-full" style="display: none;"> The galaxy group NGC6338 is one of the most violent group-group mergers known to date. While the central dominant galaxies rush at each other at 1400km/s along the line of sight, with dramatic gas heating and shock fronts detected, the central gas in the BCGs remains cool. There are also indications of feedback from active galactic nuclei (AGNs), and neither subcluster core has been disrupted. With our deep radio uGMRT data at 383MHz and 650MHz we clearly detect a set of large, old lobes in the southern BCG coinciding with the X-ray cavities, while the northern, and smaller BCG appears slightly extended in the radio. The southern BCG also hosts a smaller younger set of lobes, perpendicular to the larger lobes, but also coinciding with the inner X-ray cavities, and matching the jet direction in the parsec-resolution VLBA image. Our spectral analysis confirms the history of two feedback cycles. The high radio frequency analysis classifies the compact source in the southern BCG with a powerlaw, while ruling out a significant contribution from accretion. The radio lightcurve over 3 decades shows a change about 10 years ago, which might be related to ongoing feedback in the core. The southern BCG in the NGC6338 merger remains another prominent case where the direction of jet-mode feedback between two cycles changed dramatically. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.08833v1-abstract-full').style.display = 'none'; document.getElementById('2303.08833v1-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 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 12 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.08427">arXiv:2303.08427</a> <span> [<a href="https://arxiv.org/pdf/2303.08427">pdf</a>, <a href="https://arxiv.org/format/2303.08427">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/stad391">10.1093/mnras/stad391 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mining Mini-Halos with MeerKAT I. Calibration and Imaging </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Trehaeven%2C+K+S">K. S. Trehaeven</a>, <a href="/search/astro-ph?searchtype=author&query=Parekh%2C+V">V. Parekh</a>, <a href="/search/astro-ph?searchtype=author&query=Oozeer%2C+N">N. Oozeer</a>, <a href="/search/astro-ph?searchtype=author&query=Hugo%2C+B">B. Hugo</a>, <a href="/search/astro-ph?searchtype=author&query=Smirnov%2C+O">O. Smirnov</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardi%2C+G">G. Bernardi</a>, <a href="/search/astro-ph?searchtype=author&query=Knowles%2C+K">K. Knowles</a>, <a href="/search/astro-ph?searchtype=author&query=Tasse%2C+C">C. Tasse</a>, <a href="/search/astro-ph?searchtype=author&query=Asad%2C+K+M+B">K. M. B. Asad</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</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="2303.08427v1-abstract-short" style="display: inline;"> Radio mini-halos are clouds of diffuse, low surface brightness synchrotron emission that surround the Brightest Cluster Galaxy (BCG) in massive cool-core galaxy clusters. In this paper, we use third generation calibration (3GC), also called direction-dependent (DD) calibration, and point source subtraction on MeerKAT extragalactic continuum data. We calibrate and image archival MeerKAT L-band obse… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.08427v1-abstract-full').style.display = 'inline'; document.getElementById('2303.08427v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.08427v1-abstract-full" style="display: none;"> Radio mini-halos are clouds of diffuse, low surface brightness synchrotron emission that surround the Brightest Cluster Galaxy (BCG) in massive cool-core galaxy clusters. In this paper, we use third generation calibration (3GC), also called direction-dependent (DD) calibration, and point source subtraction on MeerKAT extragalactic continuum data. We calibrate and image archival MeerKAT L-band observations of a sample of five galaxy clusters (ACO 1413, ACO 1795, ACO 3444, MACS J1115.8+0129, MACS J2140.2-2339). We use the CARACal pipeline for direction-independent (DI) calibration, DDFacet and killMS for 3GC, followed by visibility-plane point source subtraction to image the underlying mini-halo without bias from any embedded sources. Our 3GC process shows a drastic improvement in artefact removal, to the extent that the local noise around severely affected sources was halved and ultimately resulted in a 7\% improvement in global image noise. Thereafter, using these spectrally deconvolved Stokes I continuum images, we directly measure for four mini-halos the flux density, radio power, size and in-band integrated spectra. Further to that, we show the in-band spectral index maps of the mini-halo (with point sources). We present a new mini-halo detection hosted by MACS J2140.2-2339, having flux density $S_{\rm 1.28\,GHz} = 2.61 \pm 0.31$ mJy, average diameter 296 kpc and $伪^{\rm 1.5\,GHz}_{\rm 1\,GHz} = 1.21 \pm 0.36$. We also found a $\sim$100 kpc southern extension to the ACO 3444 mini-halo which was not detected in previous VLA L-band observations. Our description of MeerKAT wide-field, wide-band data reduction will be instructive for conducting further mini-halo science. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.08427v1-abstract-full').style.display = 'none'; document.getElementById('2303.08427v1-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 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages. 10 figures</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 520, Issue 3, April 2023, Pages 4410 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.12165">arXiv:2210.12165</a> <span> [<a href="https://arxiv.org/pdf/2210.12165">pdf</a>, <a href="https://arxiv.org/format/2210.12165">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac9fd3">10.3847/1538-4357/ac9fd3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> HST and HSC Weak-lensing Study of the Equal-mass Dissociative Merger CIZA J0107.7+5408 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Finner%2C+K">Kyle Finner</a>, <a href="/search/astro-ph?searchtype=author&query=Randall%2C+S+W">Scott W. Randall</a>, <a href="/search/astro-ph?searchtype=author&query=Jee%2C+M+J">M. James Jee</a>, <a href="/search/astro-ph?searchtype=author&query=Blanton%2C+E+L">Elizabeth L. Blanton</a>, <a href="/search/astro-ph?searchtype=author&query=Cho%2C+H">Hyejeon Cho</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T+E">Tracy E. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Nulsen%2C+P">Paul Nulsen</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R">Reinout van Weeren</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="2210.12165v2-abstract-short" style="display: inline;"> A dissociative merger is formed by the interplay of ram pressure and gravitational forces, which can lead to a spatial displacement of the dark matter and baryonic components of the recently collided subclusters. CIZA J0107.7+5408 is a nearby (z=0.105) dissociative merger that hosts two X-ray brightness peaks and a bimodal galaxy distribution. Analyzing MMT/Hectospec observations, we investigate t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.12165v2-abstract-full').style.display = 'inline'; document.getElementById('2210.12165v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.12165v2-abstract-full" style="display: none;"> A dissociative merger is formed by the interplay of ram pressure and gravitational forces, which can lead to a spatial displacement of the dark matter and baryonic components of the recently collided subclusters. CIZA J0107.7+5408 is a nearby (z=0.105) dissociative merger that hosts two X-ray brightness peaks and a bimodal galaxy distribution. Analyzing MMT/Hectospec observations, we investigate the line-of-sight and spatial distribution of cluster galaxies. Utilizing deep, high-resolution Hubble Space Telescope Advanced Camera for Surveys imaging and large field-of-view Subaru Hyper-Suprime-Cam observations, we perform a weak-lensing analysis of CIZA J0107.7+5408. Our weak-lensing analysis detects a bimodal mass distribution that is spatially consistent with the cluster galaxies but significantly offset from the X-ray brightness peaks. Fitting two NFW halos to the lensing signal, we find an equal-mass merger with subcluster masses of $M_{200,NE}=2.8^{+1.1}_{-1.1}\times10^{14}$ M$_\odot$ and $M_{200,SW}=3.1^{+1.2}_{-1.2}\times10^{14}$ M$_\odot$. Moreover, the mass-to-light ratios of the subclusters, $(M/L)_{NE}=571^{+89}_{-91}$ $M_\odot/L_{\odot,B}$ and $(M/L)_{SW}=564^{+87}_{-89}$ $M_\odot/L_{\odot,B}$, are found to be consistent with each other and within the range of mass-to-light ratios found for galaxy clusters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.12165v2-abstract-full').style.display = 'none'; document.getElementById('2210.12165v2-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 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 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">15 pages, 10 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/2207.09717">arXiv:2207.09717</a> <span> [<a href="https://arxiv.org/pdf/2207.09717">pdf</a>, <a href="https://arxiv.org/format/2207.09717">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202243526">10.1051/0004-6361/202243526 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The detection of cluster magnetic fields via radio source depolarisation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Osinga%2C+E">E. Osinga</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R+J">R. J. van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Andrade-Santos%2C+F">F. Andrade-Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Rudnick%2C+L">L. Rudnick</a>, <a href="/search/astro-ph?searchtype=author&query=Bonafede%2C+A">A. Bonafede</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T">T. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Duncan%2C+K">K. Duncan</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Mroczkowski%2C+T">Tony Mroczkowski</a>, <a href="/search/astro-ph?searchtype=author&query=R%C3%B6ttgering%2C+H+J+A">H. J. A. R枚ttgering</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="2207.09717v2-abstract-short" style="display: inline;"> It has been well established that galaxy clusters have magnetic fields. The exact properties and origin of these magnetic fields are still uncertain even though these fields play a key role in many astrophysical processes. Various attempts have been made to derive the magnetic field strength and structure of nearby galaxy clusters using Faraday rotation of extended cluster radio sources. This appr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.09717v2-abstract-full').style.display = 'inline'; document.getElementById('2207.09717v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.09717v2-abstract-full" style="display: none;"> It has been well established that galaxy clusters have magnetic fields. The exact properties and origin of these magnetic fields are still uncertain even though these fields play a key role in many astrophysical processes. Various attempts have been made to derive the magnetic field strength and structure of nearby galaxy clusters using Faraday rotation of extended cluster radio sources. This approach needs to make various assumptions that could be circumvented when using background radio sources. However, because the number of polarised radio sources behind clusters is low, at the moment such a study can only be done statistically. In this paper, we investigate the depolarisation of radio sources inside and behind clusters in a sample of 124 massive clusters at $z<0.35$ observed with the Karl G. Jansky Very Large Array. We detect a clear depolarisation trend with the cluster impact parameter, with sources at smaller projected distances to the cluster centre showing more depolarisation. By combining the radio observations with ancillary X-ray data from Chandra, we compare the observed depolarisation with expectations from cluster magnetic field models using individual cluster density profiles. The best-fitting models have a central magnetic field strength of $5-10\,渭$G with power-law indices between $n=1$ and $n=4$. We find no strong difference in the depolarisation trend between sources embedded in clusters and background sources located at similar projected radii, although the central region of clusters is still poorly probed by background sources. We also examine the depolarisation trend as a function of cluster properties such as the dynamical state, mass, and redshift. Our findings show that the statistical depolarisation of radio sources is a good probe of cluster magnetic field parameters. [abridged] <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.09717v2-abstract-full').style.display = 'none'; document.getElementById('2207.09717v2-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 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">Replaced with Published version (A&A). 32 pages, 34 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 665, A71 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.06176">arXiv:2206.06176</a> <span> [<a href="https://arxiv.org/pdf/2206.06176">pdf</a>, <a href="https://arxiv.org/format/2206.06176">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac7805">10.3847/1538-4357/ac7805 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A candle in the wind: a radio filament in the core of the A3562 galaxy cluster </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Markevitch%2C+M">M. Markevitch</a>, <a href="/search/astro-ph?searchtype=author&query=Bourdin%2C+H">H. Bourdin</a>, <a href="/search/astro-ph?searchtype=author&query=Mazzotta%2C+P">P. Mazzotta</a>, <a href="/search/astro-ph?searchtype=author&query=Merluzzi%2C+P">P. Merluzzi</a>, <a href="/search/astro-ph?searchtype=author&query=Dallacasa%2C+D">D. Dallacasa</a>, <a href="/search/astro-ph?searchtype=author&query=Bardelli%2C+S">S. Bardelli</a>, <a href="/search/astro-ph?searchtype=author&query=Sikhosana%2C+S+P">S. P. Sikhosana</a>, <a href="/search/astro-ph?searchtype=author&query=Smirnov%2C+O">O. Smirnov</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardi%2C+G">G. Bernardi</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="2206.06176v1-abstract-short" style="display: inline;"> Using a MeerKAT observation of the galaxy cluster A3562 (a member of the Shapley Supercluster), we have discovered a narrow, long and straight, very faint radio filament, which branches out at a straight angle from the tail of a radio galaxy located in projection near the core of the cluster. The radio filament spans 200 kpc and aligns with a sloshing cold front seen in the X-rays, staying inside… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.06176v1-abstract-full').style.display = 'inline'; document.getElementById('2206.06176v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.06176v1-abstract-full" style="display: none;"> Using a MeerKAT observation of the galaxy cluster A3562 (a member of the Shapley Supercluster), we have discovered a narrow, long and straight, very faint radio filament, which branches out at a straight angle from the tail of a radio galaxy located in projection near the core of the cluster. The radio filament spans 200 kpc and aligns with a sloshing cold front seen in the X-rays, staying inside the front in projection. The radio spectral index along the filament appears uniform (within large uncertainties) at $伪\simeq -1.5$. We propose that the radio galaxy is located outside the cold front, but dips its tail under the front. The tangential wind that blows there may stretch the radio plasma from the radio galaxy into a filamentary structure. Some reacceleration is needed in this scenario to maintain the radio spectrum uniform. Alternatively, the cosmic ray electrons from that spot in the tail can spread along the cluster magnetic field lines, straightened by that same tangential flow, via anomalously fast diffusion. Our radio filament can provide constraints on this process. We also uncover a compact radio source at the Brightest Cluster Galaxy (BCG) that is 2--3 orders of magnitude less luminous than those in typical cluster central galaxies -- probably an example of a BCG starved of accretion fuel by gas sloshing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.06176v1-abstract-full').style.display = 'none'; document.getElementById('2206.06176v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">25 pages, 12 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.07349">arXiv:2201.07349</a> <span> [<a href="https://arxiv.org/pdf/2201.07349">pdf</a>, <a href="https://arxiv.org/format/2201.07349">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/ac71b0">10.3847/1538-4357/ac71b0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Radio Spectra of Luminous, Heavily Obscured WISE-NVSS Selected Quasars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Patil%2C+P">Pallavi Patil</a>, <a href="/search/astro-ph?searchtype=author&query=Whittle%2C+M">Mark Whittle</a>, <a href="/search/astro-ph?searchtype=author&query=Nyland%2C+K">Kristina Nyland</a>, <a href="/search/astro-ph?searchtype=author&query=Lonsdale%2C+C">Carol Lonsdale</a>, <a href="/search/astro-ph?searchtype=author&query=Lacy%2C+M">Mark Lacy</a>, <a href="/search/astro-ph?searchtype=author&query=Kimball%2C+A+E">Amy E. Kimball</a>, <a href="/search/astro-ph?searchtype=author&query=Lonsdale%2C+C">Colin Lonsdale</a>, <a href="/search/astro-ph?searchtype=author&query=Peters%2C+W">Wendy Peters</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T+E">Tracy E. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Efstathiou%2C+A">Andreas Efstathiou</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+M">Minjin Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Lanz%2C+L">Lauranne Lanz</a>, <a href="/search/astro-ph?searchtype=author&query=Mukherjee%2C+D">Dipanjan Mukherjee</a>, <a href="/search/astro-ph?searchtype=author&query=Polisensky%2C+E">Emil Polisensky</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="2201.07349v2-abstract-short" style="display: inline;"> We present radio spectra spanning $0.1 - 10$ GHz for the sample of heavily obscured luminous quasars with extremely red mid-infrared-optical colors and compact radio emission. The spectra are constructed from targeted 10 GHz observations and archival radio survey data, which together yield $6-11$ flux density measurements for each object. Our suite of Python tools for modeling the radio spectra is… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.07349v2-abstract-full').style.display = 'inline'; document.getElementById('2201.07349v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.07349v2-abstract-full" style="display: none;"> We present radio spectra spanning $0.1 - 10$ GHz for the sample of heavily obscured luminous quasars with extremely red mid-infrared-optical colors and compact radio emission. The spectra are constructed from targeted 10 GHz observations and archival radio survey data, which together yield $6-11$ flux density measurements for each object. Our suite of Python tools for modeling the radio spectra is publicly available on Github. Our primary result is that most (61%) of the sample have peaked or curved radio spectra and many (36%) could be classified as Gigahertz Peaked Spectrum (GPS) sources. This indicates compact emission regions likely arising from recently triggered radio jets. Assuming synchrotron self-absorption (SSA) generates the peaks, we infer compact source sizes ($3 - 100$ pc) with strong magnetic fields ($6 - 100$ mG) and young ages ($30 - 10^4$ years). Conversely, free-free absorption (FFA) could also create peaks due to the high column densities associated with the deeply embedded nature of the sample. However, we find no correlations between the existence or frequency of the peaks and any parameters of the MIR emission. The high-frequency spectral indices are steep ($伪\approx -1$) and correlate, weakly, with the ratio of MIR photon energy density to magnetic energy density, suggesting that the spectral steepening could arise from inverse Compton scattering off the intense MIR photon field. This study provides a foundation for combining multi-frequency and mixed-resolution radio survey data for understanding the impact of young radio jets on the ISM and star formation rates of their host galaxies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.07349v2-abstract-full').style.display = 'none'; document.getElementById('2201.07349v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">48 pages, 17 figures, published in Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.04887">arXiv:2201.04887</a> <span> [<a href="https://arxiv.org/pdf/2201.04887">pdf</a>, <a href="https://arxiv.org/format/2201.04887">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202142048">10.1051/0004-6361/202142048 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Radio footprints of a minor merger in the Shapley Supercluster: From supercluster down to galactic scales </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Merluzzi%2C+P">P. Merluzzi</a>, <a href="/search/astro-ph?searchtype=author&query=Bardelli%2C+S">S. Bardelli</a>, <a href="/search/astro-ph?searchtype=author&query=Busarello%2C+G">G. Busarello</a>, <a href="/search/astro-ph?searchtype=author&query=Dallacasa%2C+D">D. Dallacasa</a>, <a href="/search/astro-ph?searchtype=author&query=Sikhosana%2C+S+P">S. P. Sikhosana</a>, <a href="/search/astro-ph?searchtype=author&query=Marvil%2C+J">J. Marvil</a>, <a href="/search/astro-ph?searchtype=author&query=Smirnov%2C+O">O. Smirnov</a>, <a href="/search/astro-ph?searchtype=author&query=Bourdin%2C+H">H. Bourdin</a>, <a href="/search/astro-ph?searchtype=author&query=Mazzotta%2C+P">P. Mazzotta</a>, <a href="/search/astro-ph?searchtype=author&query=Rossetti%2C+M">M. Rossetti</a>, <a href="/search/astro-ph?searchtype=author&query=Rudnick%2C+L">L. Rudnick</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardi%2C+G">G. Bernardi</a>, <a href="/search/astro-ph?searchtype=author&query=Bruggen%2C+M">M. Bruggen</a>, <a href="/search/astro-ph?searchtype=author&query=Carretti%2C+E">E. Carretti</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">R. Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Gennaro%2C+G">G. Di Gennaro</a>, <a href="/search/astro-ph?searchtype=author&query=Gastaldello%2C+F">F. Gastaldello</a>, <a href="/search/astro-ph?searchtype=author&query=Kale%2C+R">R. Kale</a>, <a href="/search/astro-ph?searchtype=author&query=Knowles%2C+K">K. Knowles</a>, <a href="/search/astro-ph?searchtype=author&query=Koribalski%2C+B+S">B. S. Koribalski</a>, <a href="/search/astro-ph?searchtype=author&query=Heywood%2C+I">I. Heywood</a>, <a href="/search/astro-ph?searchtype=author&query=Hopkins%2C+A+M">A. M. Hopkins</a>, <a href="/search/astro-ph?searchtype=author&query=Norris%2C+R+P">R. P. Norris</a> , et al. (7 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2201.04887v1-abstract-short" style="display: inline;"> The Shapley Supercluster ($\langle z \rangle\approx0.048$) contains several tens of gravitationally bound clusters and groups, making it it is an ideal subject for radio studies of cluster mergers. We used new high sensitivity radio observations to investigate the less energetic events of mass assembly in the Shapley Supercluster from supercluster down to galactic scales. We created total intensit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.04887v1-abstract-full').style.display = 'inline'; document.getElementById('2201.04887v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.04887v1-abstract-full" style="display: none;"> The Shapley Supercluster ($\langle z \rangle\approx0.048$) contains several tens of gravitationally bound clusters and groups, making it it is an ideal subject for radio studies of cluster mergers. We used new high sensitivity radio observations to investigate the less energetic events of mass assembly in the Shapley Supercluster from supercluster down to galactic scales. We created total intensity images of the full region between A 3558 and A 3562, from $\sim 230$ to $\sim 1650$ MHz, using ASKAP, MeerKAT and the GMRT, with sensitivities ranging from $\sim 6$ to $\sim 100$ $渭$Jy beam$^{-1}$. We performed a detailed morphological and spectral study of the extended emission features, complemented with ESO-VST optical imaging and X-ray data from XMM-Newton. We report the first GHz frequency detection of extremely low brightness intercluster diffuse emission on a $\sim 1$ Mpc scale connecting a cluster and a group, namely: A 3562 and the group SC 1329--313. It is morphologically similar to the X-ray emission in the region. We also found (1) a radio tail generated by ram pressure stripping in the galaxy SOS 61086 in SC 1329-313; (2) a head-tail radio galaxy, whose tail is broken and culminates in a misaligned bar; (3) ultrasteep diffuse emission at the centre of A 3558. Finally (4), we confirm the ultra-steep spectrum nature of the radio halo in A 3562. Our study strongly supports the scenario of a flyby of SC 1329-313 north of A 3562 into the supercluster core. [abridged...] <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.04887v1-abstract-full').style.display = 'none'; document.getElementById('2201.04887v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 17 figures, A&A accepted</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 660, A81 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.09225">arXiv:2111.09225</a> <span> [<a href="https://arxiv.org/pdf/2111.09225">pdf</a>, <a href="https://arxiv.org/format/2111.09225">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac3b5a">10.3847/1538-4357/ac3b5a <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The unusually weak and exceptionally steep radio relic in Abell 2108 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schellenberger%2C+G">Gerrit Schellenberger</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Lovisari%2C+L">Lorenzo Lovisari</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+J">Jan Vrtilek</a>, <a href="/search/astro-ph?searchtype=author&query=David%2C+L+P">Laurence P. David</a>, <a href="/search/astro-ph?searchtype=author&query=Melin%2C+J">Jean-Baptiste Melin</a>, <a href="/search/astro-ph?searchtype=author&query=Lal%2C+D+V">Dharam Vir Lal</a>, <a href="/search/astro-ph?searchtype=author&query=Ettori%2C+S">Stefano Ettori</a>, <a href="/search/astro-ph?searchtype=author&query=Kolokythas%2C+K">Konstantinos Kolokythas</a>, <a href="/search/astro-ph?searchtype=author&query=Sereno%2C+M">Mauro Sereno</a>, <a href="/search/astro-ph?searchtype=author&query=Raychaudhury%2C+S">Somak Raychaudhury</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="2111.09225v1-abstract-short" style="display: inline;"> Mergers between galaxy clusters often drive shocks into the intra cluster medium (ICM), the effects of which are sometimes visible via temperature and density jumps in the X-ray, and via radio emission from relativistic particles energized by the shock's passage. Abell2108 was selected as a likely merger system through comparing the X-ray luminosity to the Planck Sunyaev-Zeldovich signal, where th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.09225v1-abstract-full').style.display = 'inline'; document.getElementById('2111.09225v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.09225v1-abstract-full" style="display: none;"> Mergers between galaxy clusters often drive shocks into the intra cluster medium (ICM), the effects of which are sometimes visible via temperature and density jumps in the X-ray, and via radio emission from relativistic particles energized by the shock's passage. Abell2108 was selected as a likely merger system through comparing the X-ray luminosity to the Planck Sunyaev-Zeldovich signal, where this cluster appeared highly X-ray underluminous. Follow up observations confirmed it to be a merging low mass cluster featuring two distinct subclusters, both with a highly disturbed X-ray morphology. Giant Metrewave Radio Telescope (GMRT) data covering 120-750MHz show an extended radio feature resembling a radio relic, near the location of a temperature discontinuity in the X-rays. We measure a Mach number from the X-ray temperature jump. Several characteristics of radio relics are found in Abell2108, making this cluster one of the few low mass mergers likely hosting a radio relic. The radio spectrum is exceptionally steep, and the radio power is very weak (P1.4GHz=1E22W/Hz). To account for the shock/relic offset, we propose a scenario in which the shock created the relic by re-accelerating a cloud of pre-existing relativistic electrons and then moved away, leaving behind a fading relic. The electron aging timescale derived from the high-frequency steepening in the relic spectrum is consistent with the shock travel time to the observed X-ray discontinuity. However, the lower flux in GMRT band 4 data causing the steepening could be due to instrumental limitations, and deeper radio data are needed to constrain the spectral slope of the relic at high frequencies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.09225v1-abstract-full').style.display = 'none'; document.getElementById('2111.09225v1-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 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">accepted for publication in ApJ; 15 pages, 6 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/2110.08358">arXiv:2110.08358</a> <span> [<a href="https://arxiv.org/pdf/2110.08358">pdf</a>, <a href="https://arxiv.org/format/2110.08358">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/10.1002/asna.20210035">10.1002/asna.20210035 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> 1321+045: a Compact Steep Spectrum radio source in a cool-core galaxy cluster </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Kunert-Bajraszewska%2C+M">Magdalena Kunert-Bajraszewska</a>, <a href="/search/astro-ph?searchtype=author&query=Siemiginowska%2C+A">Aneta Siemiginowska</a>, <a href="/search/astro-ph?searchtype=author&query=Burke%2C+D+J">D. J. Burke</a>, <a href="/search/astro-ph?searchtype=author&query=Combes%2C+F">Francoise Combes</a>, <a href="/search/astro-ph?searchtype=author&query=Salome%2C+P">Philippe Salome</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</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="2110.08358v1-abstract-short" style="display: inline;"> Cluster-central gigahertz peak and compact steep spectrum (CSS) sources offer an opportunity to study the earliest phases of AGN feedback, but few have yet been examined in detail. We present results from radio and X-ray observations of 1321+045, a CSS source in a 4.4 keV cluster at z=0.263. The cluster has a strongly cooling core, and disturbances from a minor cluster merger may have triggered a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.08358v1-abstract-full').style.display = 'inline'; document.getElementById('2110.08358v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.08358v1-abstract-full" style="display: none;"> Cluster-central gigahertz peak and compact steep spectrum (CSS) sources offer an opportunity to study the earliest phases of AGN feedback, but few have yet been examined in detail. We present results from radio and X-ray observations of 1321+045, a CSS source in a 4.4 keV cluster at z=0.263. The cluster has a strongly cooling core, and disturbances from a minor cluster merger may have triggered a period of jet activity which formed the 16 kpc radio lobes 2.0 [+0.3,-0.2] Myr ago. However, new VLBA imaging shows a ~20 pc jet on a different projected axis, which is probably only a few hundred years old. We consider possible histories for the system, with either one or two periods of jet activity. While this single system is informative, a broader study of the youngest cluster-central radio sources is desirable. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.08358v1-abstract-full').style.display = 'none'; document.getElementById('2110.08358v1-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 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">4 pages, accepted for publication on Astronomische Nachrichten, as part of the proceedings of the 6th Workshop on Compact Steep-Spectrum and GHz-Peaked Spectrum radio sources</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.01629">arXiv:2110.01629</a> <span> [<a href="https://arxiv.org/pdf/2110.01629">pdf</a>, <a href="https://arxiv.org/format/2110.01629">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stab2840">10.1093/mnras/stab2840 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The ultra-steep diffuse radio emission observed in the cool-core cluster RX J1720.1+2638 with LOFAR at 54 MHz </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Biava%2C+N">N. Biava</a>, <a href="/search/astro-ph?searchtype=author&query=de+Gasperin%2C+F">F. de Gasperin</a>, <a href="/search/astro-ph?searchtype=author&query=Bonafede%2C+A">A. Bonafede</a>, <a href="/search/astro-ph?searchtype=author&query=Edler%2C+H+W">H. W. Edler</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Mazzotta%2C+P">P. Mazzotta</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">G. Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Botteon%2C+A">A. Botteon</a>, <a href="/search/astro-ph?searchtype=author&query=Br%C3%BCggen%2C+M">M. Br眉ggen</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">R. Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Drabent%2C+A">A. Drabent</a>, <a href="/search/astro-ph?searchtype=author&query=Edge%2C+A+C">A. C. Edge</a>, <a href="/search/astro-ph?searchtype=author&query=En%C3%9Flin%2C+T">T. En脽lin</a>, <a href="/search/astro-ph?searchtype=author&query=Gastaldello%2C+F">F. Gastaldello</a>, <a href="/search/astro-ph?searchtype=author&query=Riseley%2C+C+J">C. J. Riseley</a>, <a href="/search/astro-ph?searchtype=author&query=Rossetti%2C+M">M. Rossetti</a>, <a href="/search/astro-ph?searchtype=author&query=Rottgering%2C+H+J+A">H. J. A. Rottgering</a>, <a href="/search/astro-ph?searchtype=author&query=Shimwell%2C+T+W">T. W. Shimwell</a>, <a href="/search/astro-ph?searchtype=author&query=Tasse%2C+C">C. Tasse</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R+J">R. J. van Weeren</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="2110.01629v1-abstract-short" style="display: inline;"> Diffuse radio emission at the centre of galaxy clusters has been observed both in merging clusters on scales of Mpc, called giant radio haloes, and in relaxed systems with a cool-core on smaller scales, named mini haloes. Giant radio haloes and mini haloes are thought to be distinct classes of sources. However, recent observations have revealed the presence of diffuse radio emission on Mpc scales… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.01629v1-abstract-full').style.display = 'inline'; document.getElementById('2110.01629v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.01629v1-abstract-full" style="display: none;"> Diffuse radio emission at the centre of galaxy clusters has been observed both in merging clusters on scales of Mpc, called giant radio haloes, and in relaxed systems with a cool-core on smaller scales, named mini haloes. Giant radio haloes and mini haloes are thought to be distinct classes of sources. However, recent observations have revealed the presence of diffuse radio emission on Mpc scales in clusters that do not show strong dynamical activity. RX J1720.1+2638 is a cool-core cluster, presenting both a bright central mini halo and a fainter diffuse, steep-spectrum emission extending beyond the cluster core that resembles giant radio halo emission. In this paper, we present new observations performed with the LOFAR Low Band Antennas (LBA) at 54 MHz. These observations, combined with data at higher frequencies, allow us to constrain the spectral properties of the radio emission. The large-scale emission presents an ultra-steep spectrum with $伪_{54}^{144}\sim3.2$. The radio emission inside and outside the cluster core have strictly different properties, as there is a net change in spectral index and they follow different radio-X-ray surface brightness correlations. We argue that the large-scale diffuse emission is generated by particles re-acceleration after a minor merger. While for the central mini halo we suggest that it could be generated by secondary electrons and positrons from hadronic interactions of relativistic nuclei with the dense cool-core gas, as an alternative to re-acceleration models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.01629v1-abstract-full').style.display = 'none'; document.getElementById('2110.01629v1-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 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">13 pages, 10 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/2105.03282">arXiv:2105.03282</a> <span> [<a href="https://arxiv.org/pdf/2105.03282">pdf</a>, <a href="https://arxiv.org/ps/2105.03282">ps</a>, <a href="https://arxiv.org/format/2105.03282">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/stab1979">10.1093/mnras/stab1979 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Two Extreme Steep-Spectrum, Polarized Radio Sources Towards the Galactic Bulge </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hyman%2C+S+D">S. D. Hyman</a>, <a href="/search/astro-ph?searchtype=author&query=Frail%2C+D+A">D. A. Frail</a>, <a href="/search/astro-ph?searchtype=author&query=Deneva%2C+J+S">J. S. Deneva</a>, <a href="/search/astro-ph?searchtype=author&query=Kassim%2C+N+E">N. E. Kassim</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Kooi%2C+J+E">J. E. Kooi</a>, <a href="/search/astro-ph?searchtype=author&query=Lazio%2C+T+J+W">T. J. W. Lazio</a>, <a href="/search/astro-ph?searchtype=author&query=Joyner%2C+I">I. Joyner</a>, <a href="/search/astro-ph?searchtype=author&query=Peters%2C+W+M">W. M. Peters</a>, <a href="/search/astro-ph?searchtype=author&query=Gajjar%2C+V">V. Gajjar</a>, <a href="/search/astro-ph?searchtype=author&query=Siemion%2C+A+P+V">A. P. V. Siemion</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="2105.03282v1-abstract-short" style="display: inline;"> From an on-going survey of the Galactic bulge, we have discovered a number of compact, steep spectrum radio sources. In this present study we have carried out more detailed observations for two of these sources, located 43 arcmin and 12.7 deg from the Galactic Center. Both sources have a very steep spectrum (alpha ~ -3) and are compact, with upper limits on the angular size of 1-2 arcsec. Their fl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.03282v1-abstract-full').style.display = 'inline'; document.getElementById('2105.03282v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2105.03282v1-abstract-full" style="display: none;"> From an on-going survey of the Galactic bulge, we have discovered a number of compact, steep spectrum radio sources. In this present study we have carried out more detailed observations for two of these sources, located 43 arcmin and 12.7 deg from the Galactic Center. Both sources have a very steep spectrum (alpha ~ -3) and are compact, with upper limits on the angular size of 1-2 arcsec. Their flux densities appear to be relatively steady on timescales of years, months, and hours, with no indications of rapid variability or transient behavior. We detect significant circularly polarized emission from both sources, but only weak or upper limits on linear polarization. Neither source has a counterpart at other wavelengths and deep, high-frequency searches fail to find pulsations. We compare their source properties with other known compact, non-thermal source populations in the bulge (e.g. X-ray binaries, magnetars, the Burper, cataclysmic variables). Our existing data support the hypothesis that they are scatter broadened millisecond or recycled pulsars, either at the bulge or along the line of sight. We also consider the possibility that they may be a new population of Galactic radio sources which share similar properties as pulsars but lack pulsations; a hypothesis that can be tested by future large-scale synoptic surveys. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.03282v1-abstract-full').style.display = 'none'; document.getElementById('2105.03282v1-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 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">12 pages, 4 figures. Submitted to 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/2104.05619">arXiv:2104.05619</a> <span> [<a href="https://arxiv.org/pdf/2104.05619">pdf</a>, <a href="https://arxiv.org/format/2104.05619">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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/10.1093/mnras/stab964">10.1093/mnras/stab964 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A MeerKAT view on galaxy clusters: a radio-optical study of Abell 1300 and MACS J1931.8--2634 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=de+Gregory%2C+B+T">B. Terni de Gregory</a>, <a href="/search/astro-ph?searchtype=author&query=Hugo%2C+B">B. Hugo</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardi%2C+G">G. Bernardi</a>, <a href="/search/astro-ph?searchtype=author&query=Dallacasa%2C+D">D. Dallacasa</a>, <a href="/search/astro-ph?searchtype=author&query=Nonino%2C+M">M. Nonino</a>, <a href="/search/astro-ph?searchtype=author&query=Makhatini%2C+S">S. Makhatini</a>, <a href="/search/astro-ph?searchtype=author&query=Parekh%2C+V">V. Parekh</a>, <a href="/search/astro-ph?searchtype=author&query=Smirnov%2C+O+M">O. M. Smirnov</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Kale%2C+R">R. Kale</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="2104.05619v1-abstract-short" style="display: inline;"> In this paper we present results from a radio-optical study of the galaxy populations of the galaxy clusters Abell 1300 and MACS J1931.8$-$2634, a merger and a relaxed system respectively both located at $z \sim 0.3$, aimed at finding evidence of merger-induced radio emission. Radio observations are taken at 1.28 GHz with the MeerKAT interferometer during its early-stage commissioning phase, and c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.05619v1-abstract-full').style.display = 'inline'; document.getElementById('2104.05619v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.05619v1-abstract-full" style="display: none;"> In this paper we present results from a radio-optical study of the galaxy populations of the galaxy clusters Abell 1300 and MACS J1931.8$-$2634, a merger and a relaxed system respectively both located at $z \sim 0.3$, aimed at finding evidence of merger-induced radio emission. Radio observations are taken at 1.28 GHz with the MeerKAT interferometer during its early-stage commissioning phase, and combined with archive optical data. We generated catalogues containing 107 and 162 radio sources in the A$~$1300 and MACS J1931.8--2634 cluster fields respectively, above a 0.2 mJy threshold and within a 30~arcmin radius from the cluster centre (corresponding to 8.1 and 8.8 Mpc respectively). By cross-correlating the radio and optical catalogues, and including spectroscopic information, 9 and 6 sources were found to be cluster members and used to construct the radio luminosity functions respectively for both clusters. The comparison of the radio source catalogues between the two cluster fields leads to a marginal difference, with a $2蟽$ statistical significance. We derived the radio luminosity function at 1.28 GHz in both clusters, in the power range $22.81 < \rm {log~P_{1.28~GHz}~(W/Hz)} < 25.95$, and obtained that in A 1300 the radio luminosity function averaged over the full radio power interval is only $3.3 \pm 1.9$ times higher than the MACS J1931.8--2634 one, suggesting no statistical difference in their probability to host nuclear radio emission. We conclude that, at least for the two clusters studied here, the role of cluster mergers in affecting the statistical properties of the radio galaxy population is negligible. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.05619v1-abstract-full').style.display = 'none'; document.getElementById('2104.05619v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 8 figures, MNRAS accepted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.04548">arXiv:2104.04548</a> <span> [<a href="https://arxiv.org/pdf/2104.04548">pdf</a>, <a href="https://arxiv.org/format/2104.04548">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/abf6c6">10.3847/1538-4357/abf6c6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The cluster-central compact steep-spectrum radio galaxy 1321+045 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Kunert-Bajraszewska%2C+M">Magdalena Kunert-Bajraszewska</a>, <a href="/search/astro-ph?searchtype=author&query=Siemiginowska%2C+A">Aneta Siemiginowska</a>, <a href="/search/astro-ph?searchtype=author&query=Burke%2C+D+J">D. J. Burke</a>, <a href="/search/astro-ph?searchtype=author&query=Combes%2C+F">Fran莽oise Combes</a>, <a href="/search/astro-ph?searchtype=author&query=Salom%C3%A9%2C+P">Philippe Salom茅</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</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="2104.04548v2-abstract-short" style="display: inline;"> The radio galaxy 1321+045 is a rare example of a young, compact steep spectrum source located in the center of a z=0.263 galaxy cluster. Using a combination of Chandra, VLBA, VLA, MERLIN and IRAM 30m observations, we investigate the conditions which have triggered this outburst. We find that the previously identified 5 kpc scale radio lobes are probably no longer powered by the AGN, which seems to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.04548v2-abstract-full').style.display = 'inline'; document.getElementById('2104.04548v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.04548v2-abstract-full" style="display: none;"> The radio galaxy 1321+045 is a rare example of a young, compact steep spectrum source located in the center of a z=0.263 galaxy cluster. Using a combination of Chandra, VLBA, VLA, MERLIN and IRAM 30m observations, we investigate the conditions which have triggered this outburst. We find that the previously identified 5 kpc scale radio lobes are probably no longer powered by the AGN, which seems to have launched a new ~20 pc jet on a different axis, likely within the last few hundred years. We estimate the enthalpy of the lobes to be 8.48 [+6.04,-3.56] x10^57 erg, only sufficient to balance cooling in the surrounding 16 kpc for ~9 Myr. The cluster ICM properties are similar to those of rapidly cooling nearby clusters, with a low central entropy (8.6 [+2.2,-1.4] kev cm^2 within 8 kpc), short central cooling time (390 [+170,-150] Myr), and t_cool/t_ff and t_cool/t_eddy ratios indicative of thermal instability out to ~45 kpc. Despite previous detection of Halpha emission from the BCG, our IRAM 30m observations do not detect CO emission in either the (1-0) or (3-2) transitions. We place 3sigma limits on the molecular gas mass of M_mol <=7.7x10^9 Msol and <=5.6x10^9 Msol from the two lines respectively. We find indications of a recent minor cluster merger which has left a ~200 kpc tail of stripped gas in the ICM, and probably induced sloshing motions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.04548v2-abstract-full').style.display = 'none'; document.getElementById('2104.04548v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 9 figures, 4 tables, accepted for publication in ApJ, v2 updates references and corrects minor typographical errors identified at the proof stage</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.07545">arXiv:2103.07545</a> <span> [<a href="https://arxiv.org/pdf/2103.07545">pdf</a>, <a href="https://arxiv.org/format/2103.07545">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/abf73e">10.3847/1538-4357/abf73e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Chandra Observations of the Planck ESZ Sample: A Re-Examination of Masses and Mass Proxies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Andrade-Santos%2C+F">Felipe Andrade-Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Pratt%2C+G+W">Gabriel W. Pratt</a>, <a href="/search/astro-ph?searchtype=author&query=Melin%2C+J">Jean-Baptiste Melin</a>, <a href="/search/astro-ph?searchtype=author&query=Arnaud%2C+M">Monique Arnaud</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+C">Christine Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Forman%2C+W+R">William R. Forman</a>, <a href="/search/astro-ph?searchtype=author&query=Pointecouteau%2C+E">Etienne Pointecouteau</a>, <a href="/search/astro-ph?searchtype=author&query=Bartalucci%2C+I">Iacopo Bartalucci</a>, <a href="/search/astro-ph?searchtype=author&query=Vikhlinin%2C+A">Alexey Vikhlinin</a>, <a href="/search/astro-ph?searchtype=author&query=Murray%2C+S+S">Stephen S. Murray</a>, <a href="/search/astro-ph?searchtype=author&query=Mazzotta%2C+P">Pasquale Mazzotta</a>, <a href="/search/astro-ph?searchtype=author&query=Borgani%2C+S">Stefano Borgani</a>, <a href="/search/astro-ph?searchtype=author&query=Lovisari%2C+L">Lorenzo Lovisari</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R+J">Reinout J. van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Kraft%2C+R+P">Ralph P. Kraft</a>, <a href="/search/astro-ph?searchtype=author&query=David%2C+L+P">Laurence P. David</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</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="2103.07545v2-abstract-short" style="display: inline;"> Using Chandra observations, we derive the $Y_{\rm X}$ proxy and associated total mass measurement, $M_{500}^{\rm Y_X}$, for 147 clusters with $z \leq 0.35$ from the Planck Early Sunyaev-Zel'dovich catalog, and for 80 clusters with $z \leq 0.30$ from an X-ray flux-limited sample. We re-extract the Planck $Y_{\rm SZ}$ measurements and obtain the corresponding mass proxy, $M_{500}^{\rm SZ}$, from the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.07545v2-abstract-full').style.display = 'inline'; document.getElementById('2103.07545v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.07545v2-abstract-full" style="display: none;"> Using Chandra observations, we derive the $Y_{\rm X}$ proxy and associated total mass measurement, $M_{500}^{\rm Y_X}$, for 147 clusters with $z \leq 0.35$ from the Planck Early Sunyaev-Zel'dovich catalog, and for 80 clusters with $z \leq 0.30$ from an X-ray flux-limited sample. We re-extract the Planck $Y_{\rm SZ}$ measurements and obtain the corresponding mass proxy, $M_{500}^{\rm SZ}$, from the full Planck mission maps, minimizing the Malmquist bias due to observational scatter. The masses re-extracted using the more precise X-ray position and characteristic size agree with the published PSZ2 values, but yield a significant reduction in the scatter (by a factor of two) in the $M_{500}^{\rm SZ}$-$M_{500}^{\rm X}$ relation. The slope is $0.93\pm0.03$, and the median ratio, $M_{500}^{\rm SZ}/M_{500}^{\rm X}= 0.91\pm0.01$, is within the expectations from known X-ray calibration systematics. The $Y_{\rm SZ}/Y_{\rm X}$ ratio is $0.88\pm0.02$, in good agreement with predictions from cluster structure, and implying a low level of clumpiness. In agreement with the findings of the Planck Collaboration, the slope of the $Y_{\rm SZ}$-$D_{\rm A}^{-2} Y_{X}$ flux relation is significantly less than unity ($0.89\pm0.01$). Using extensive simulations, we show that this result is not due to selection effects, intrinsic scatter, or covariance between quantities. We demonstrate analytically that changing the $Y_{\rm SZ}$-$Y_{X}$ relation from apparent flux to intrinsic properties results in a best-fit slope that is closer to unity and increases the dispersion about the relation. The redistribution resulting from this transformation implies that the best fit parameters of the $M_{500}^{\rm SZ}$-$M_{500}^{\rm X}$ relation will be sample-dependent. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.07545v2-abstract-full').style.display = 'none'; document.getElementById('2103.07545v2-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 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">28 pages, 15 figures, and 6 tables. Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.01989">arXiv:2103.01989</a> <span> [<a href="https://arxiv.org/pdf/2103.01989">pdf</a>, <a href="https://arxiv.org/format/2103.01989">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202040083">10.1051/0004-6361/202040083 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nonthermal phenomena in the center of Abell 1775: An 800 kpc head-tail, revived fossil plasma and slingshot radio halo </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Botteon%2C+A">A. Botteon</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Gastaldello%2C+F">F. Gastaldello</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">G. Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R+J">R. J. van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Shimwell%2C+T+W">T. W. Shimwell</a>, <a href="/search/astro-ph?searchtype=author&query=Rossetti%2C+M">M. Rossetti</a>, <a href="/search/astro-ph?searchtype=author&query=Akamatsu%2C+H">H. Akamatsu</a>, <a href="/search/astro-ph?searchtype=author&query=Br%C3%BCggen%2C+M">M. Br眉ggen</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">R. Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Cuciti%2C+V">V. Cuciti</a>, <a href="/search/astro-ph?searchtype=author&query=de+Gasperin%2C+F">F. de Gasperin</a>, <a href="/search/astro-ph?searchtype=author&query=Drabent%2C+A">A. Drabent</a>, <a href="/search/astro-ph?searchtype=author&query=Hoeft%2C+M">M. Hoeft</a>, <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">S. Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=R%C3%B6ttgering%2C+H+J+A">H. J. A. R枚ttgering</a>, <a href="/search/astro-ph?searchtype=author&query=Tasse%2C+C">C. Tasse</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="2103.01989v2-abstract-short" style="display: inline;"> Thermal gas in the center of galaxy clusters can show substantial motions that generate surface-brightness and temperature discontinuities known as cold fronts. The motions may be triggered by minor or off-axis mergers that preserve the cool core of the system. The dynamics of the thermal gas can also generate radio emission from the intra-cluster medium (ICM) and impact the evolution of clusters'… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.01989v2-abstract-full').style.display = 'inline'; document.getElementById('2103.01989v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.01989v2-abstract-full" style="display: none;"> Thermal gas in the center of galaxy clusters can show substantial motions that generate surface-brightness and temperature discontinuities known as cold fronts. The motions may be triggered by minor or off-axis mergers that preserve the cool core of the system. The dynamics of the thermal gas can also generate radio emission from the intra-cluster medium (ICM) and impact the evolution of clusters' radio sources. We aim to study the central region of Abell 1775, a system in an ambiguous dynamical state at $z=0.072$ which is known to host an extended head-tail radio galaxy, with the goal of investigating the connection between thermal and nonthermal components in its center. We made use of a deep (100 ks) Chandra observation accompanied by LOFAR 144 MHz, GMRT 235 MHz and 610 MHz, and VLA 1.4 GHz radio data. We find a spiral-like pattern in the X-ray surface brightness that is mirrored in the temperature and pseudo-entropy maps. Additionally, we characterize an arc-shaped cold front in the ICM. We interpret these features in the context of a slingshot gas tail scenario. The structure of the head-tail radio galaxy "breaks" at the position of the cold front, showing an extension that is detected only at low frequencies, likely due to its steep and curved spectrum. We speculate that particle reacceleration is occurring in the outer region of this tail, which in total covers a projected size of $\sim800$ kpc. We also report the discovery of revived fossil plasma with ultra-steep spectrum radio emission in the cluster core together with a central diffuse radio source that is bounded by the arc-shaped cold front. The results reported in this work demonstrate the interplay between thermal and nonthermal components in the cluster center and the presence of ongoing particle reacceleration in the ICM on different scales. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.01989v2-abstract-full').style.display = 'none'; document.getElementById('2103.01989v2-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 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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, 17 figures, 2 tables (including appendix); Updated to match the accepted version 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 649, A37 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.01641">arXiv:2101.01641</a> <span> [<a href="https://arxiv.org/pdf/2101.01641">pdf</a>, <a href="https://arxiv.org/format/2101.01641">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </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/10.1051/0004-6361/202039208">10.1051/0004-6361/202039208 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Radio halos in a mass-selected sample of 75 galaxy clusters. II. Statistical analysis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cuciti%2C+V">V. Cuciti</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">R. Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">G. Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Dallacasa%2C+D">D. Dallacasa</a>, <a href="/search/astro-ph?searchtype=author&query=de+Gasperin%2C+F">F. de Gasperin</a>, <a href="/search/astro-ph?searchtype=author&query=Ettori%2C+S">S. Ettori</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Kale%2C+R">R. Kale</a>, <a href="/search/astro-ph?searchtype=author&query=Pratt%2C+G+W">G. W. Pratt</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R+J">R. J. van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</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="2101.01641v1-abstract-short" style="display: inline;"> Many galaxy clusters host Mpc scale diffuse radio sources called radio halos. Their origin is connected to the processes that lead to the formation of clusters themselves. In order to unveil this connection, statistical studies of radio halos are necessary. We selected a sample of galaxy clusters with M500>6e14Msun and z=0.08-0.33 from the Planck SZ catalogue. In paper I, we presented the radio an… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.01641v1-abstract-full').style.display = 'inline'; document.getElementById('2101.01641v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.01641v1-abstract-full" style="display: none;"> Many galaxy clusters host Mpc scale diffuse radio sources called radio halos. Their origin is connected to the processes that lead to the formation of clusters themselves. In order to unveil this connection, statistical studies of radio halos are necessary. We selected a sample of galaxy clusters with M500>6e14Msun and z=0.08-0.33 from the Planck SZ catalogue. In paper I, we presented the radio and X-ray data analysis that we carried out on these clusters. Here, we study the radio properties of the sample, in connection to the mass and dynamical state of clusters. We used the dynamical information derived from the X-ray data to assess the role of mergers in the origin of radio halos. We studied the distribution of clusters in the radio power-mass diagram and the role of dynamics on the radio luminosity and emissivity of radio halos. We measured the occurrence of radio halos as a function of the cluster mass and we compared it with the expectations of turbulent acceleration models. We found that more than the 90% of radio halos are in merging clusters and that their radio power correlates with the mass of the host clusters. The correlation shows a large dispersion. Interestingly, we showed that cluster dynamics contributes significantly to this dispersion with more disturbed clusters being more radio luminous. Clusters without radio halos are generally relaxed and the upper limits to their diffuse emission lie below the correlation. We showed that the radio emissivity of clusters exhibits an apparent bimodality, with the emissivity of radio halos being at least 5 times larger than the non-emission associated with more relaxed clusters. We found that the fraction of radio halos drops from ~70% in high mass clusters to ~35% in the lower mass systems of the sample and we showed that this result is in good agreement with the expectations from turbulent re-acceleration models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.01641v1-abstract-full').style.display = 'none'; document.getElementById('2101.01641v1-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 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 10 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 647, A51 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.01640">arXiv:2101.01640</a> <span> [<a href="https://arxiv.org/pdf/2101.01640">pdf</a>, <a href="https://arxiv.org/format/2101.01640">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </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/10.1051/0004-6361/202039206">10.1051/0004-6361/202039206 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Radio halos in a mass-selected sample of 75 galaxy clusters. I. Sample selection and data analysis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cuciti%2C+V">V. Cuciti</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">R. Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">G. Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Dallacasa%2C+D">D. Dallacasa</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R+J">R. J. van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Bonafede%2C+A">A. Bonafede</a>, <a href="/search/astro-ph?searchtype=author&query=de+Gasperin%2C+F">F. de Gasperin</a>, <a href="/search/astro-ph?searchtype=author&query=Ettori%2C+S">S. Ettori</a>, <a href="/search/astro-ph?searchtype=author&query=Kale%2C+R">R. Kale</a>, <a href="/search/astro-ph?searchtype=author&query=Pratt%2C+G+W">G. W. Pratt</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</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="2101.01640v1-abstract-short" style="display: inline;"> Radio halos are synchrotron diffuse sources at the centre of a fraction of galaxy clusters. The study of large samples of clusters with adequate radio and X-ray data is necessary to investigate the origin of radio halos and their connection with the cluster dynamics and formation history. The aim of this paper is to compile a well-selected sample of galaxy clusters with deep radio observations to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.01640v1-abstract-full').style.display = 'inline'; document.getElementById('2101.01640v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.01640v1-abstract-full" style="display: none;"> Radio halos are synchrotron diffuse sources at the centre of a fraction of galaxy clusters. The study of large samples of clusters with adequate radio and X-ray data is necessary to investigate the origin of radio halos and their connection with the cluster dynamics and formation history. The aim of this paper is to compile a well-selected sample of galaxy clusters with deep radio observations to perform an unbiased statistical study of the properties of radio halos. We selected 75 clusters with M > = 6e14 Msun at z=0.08-0.33 from the Planck Sunyaev-Zel'dovich catalogue. Clusters without suitable radio data were observed with the Giant Metrewave Radio Telescope (GMRT) and/or the Jansky Very Large Array (JVLA) to complete the information about the possible presence of diffuse emission. We used archival Chandra X-ray data to derive information on the clusters' dynamical states. This observational campaign led to the detection of several cluster-scale diffuse radio sources and candidates that deserve future follow-up observations. Here we summarise their properties and add information resulting from our new observations. For the clusters where we did not detect any hint of diffuse emission, we derived new upper limits to their diffuse flux. We have built the largest mass-selected (> 80 per cent complete in mass) sample of galaxy clusters with deep radio observations available to date. The statistical analysis of the sample, which includes the connection between radio halos and cluster mergers, the radio power-mass correlation, and the occurrence of radio halos as a function of the cluster mass, will be presented in paper II. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.01640v1-abstract-full').style.display = 'none'; document.getElementById('2101.01640v1-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 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">35 pages, 42 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 647, A50 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.00236">arXiv:2012.00236</a> <span> [<a href="https://arxiv.org/pdf/2012.00236">pdf</a>, <a href="https://arxiv.org/ps/2012.00236">ps</a>, <a href="https://arxiv.org/format/2012.00236">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/abcbf7">10.3847/1538-4357/abcbf7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> NuSTAR Observations of Abell 2163: Constraints on Non-thermal Emission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bolivar%2C+R+R">Randall Rojas Bolivar</a>, <a href="/search/astro-ph?searchtype=author&query=Wik%2C+D">Daniel Wik</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Gastaldello%2C+F">Fabio Gastaldello</a>, <a href="/search/astro-ph?searchtype=author&query=Hornstrup%2C+A">Allan Hornstrup</a>, <a href="/search/astro-ph?searchtype=author&query=Westergaard%2C+N">Niels-Jorgen Westergaard</a>, <a href="/search/astro-ph?searchtype=author&query=Madjeski%2C+G">Grzegorz Madjeski</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="2012.00236v1-abstract-short" style="display: inline;"> Since the first non-thermal reports of inverse Compton (IC) emission from the intracluster medium (ICM) of galaxy clusters at hard X-ray energies, we have yet to unambiguously confirm IC emission in observations with newer facilities. RXTE detected IC emission in one of the hottest known clusters, Abell 2163 (A2163), a massive merging cluster with a giant radio halo--the presumed source of relativ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.00236v1-abstract-full').style.display = 'inline'; document.getElementById('2012.00236v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.00236v1-abstract-full" style="display: none;"> Since the first non-thermal reports of inverse Compton (IC) emission from the intracluster medium (ICM) of galaxy clusters at hard X-ray energies, we have yet to unambiguously confirm IC emission in observations with newer facilities. RXTE detected IC emission in one of the hottest known clusters, Abell 2163 (A2163), a massive merging cluster with a giant radio halo--the presumed source of relativistic electrons IC scattering CMB photons to X-ray energies. The cluster's redshift (z~0.2) allows its thermal and non-thermal radio emission to fit NuSTARS's FOV, permitting a deep observation capable of confirming or ruling out the RXTE report. The IC flux provides constraints on the average magnetic field strength in a cluster. To determine the global diffuse IC emission in A2163, we fit its global NuSTAR spectrum with four models: single (1T) and two-temperature (2T), 1T+power law component (T+IC), and multi-temperature+power law (9T+IC). Each represent different characterizations of the thermal ICM emission, with power law components added to represent IC emission. We find the 3-30 keV spectrum can be described by purely thermal emission, with a global average temperature of kT = (11.8 $\pm$ 0.2) keV. The IC flux is constrained to $<$ $4.0$ $\times$ $10^{-12}$ $erg$ $s^{-1}$ $cm^{-2}$ using the 1T+IC model and $<$ $1.6$ $\times$ $10^{-12}$ $erg$ $s^{-1}$ $cm^{-2}$ with the more physical 9T+IC model, both to 90% confidence levels. Combining these limits with 1.4 GHz diffuse radio data from the VLA, we find the average magnetic field strength to be $>$ $0.22$$渭$$G$ and $>$ $0.35$$渭$$G$, respectively, providing the strongest constraints on these values in A2163 to date. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.00236v1-abstract-full').style.display = 'none'; document.getElementById('2012.00236v1-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 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 17 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/2010.13804">arXiv:2010.13804</a> <span> [<a href="https://arxiv.org/pdf/2010.13804">pdf</a>, <a href="https://arxiv.org/format/2010.13804">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/abc488">10.3847/1538-4357/abc488 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A new feedback cycle in the archetypal cooling flow group NGC 5044 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schellenberger%2C+G">Gerrit Schellenberger</a>, <a href="/search/astro-ph?searchtype=author&query=David%2C+L+P">Laurence P. David</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+J">Jan Vrtilek</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Forman%2C+W">William Forman</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+C">Christine Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">Tiziana Venturi</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="2010.13804v1-abstract-short" style="display: inline;"> The fate of cooling gas in the centers of galaxy clusters and groups is still not well understood, as is also the case for the complex process of triggering active galactic nucleus (AGN) outbursts in their central dominant galaxies, and the consequent re-heating of the gas by the AGN jets. With the largest known reservoir of cold molecular gas of any group-dominant galaxy and three epochs of AGN a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.13804v1-abstract-full').style.display = 'inline'; document.getElementById('2010.13804v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.13804v1-abstract-full" style="display: none;"> The fate of cooling gas in the centers of galaxy clusters and groups is still not well understood, as is also the case for the complex process of triggering active galactic nucleus (AGN) outbursts in their central dominant galaxies, and the consequent re-heating of the gas by the AGN jets. With the largest known reservoir of cold molecular gas of any group-dominant galaxy and three epochs of AGN activity visible as cavities in its hot gas, NGC 5044 is an ideal system in which to study the cooling/AGN feedback cycle at the group scale. We present VLBA observations of NGC 5044 to ascertain the current state of the central AGN. We find a compact core and two small jets aligned almost in the plane of the sky, and in the orthogonal direction to the location of cavities. We construct the radio/sub-mm spectral energy distribution (SED) over more than three orders of magnitude. We find that below 5 GHz the spectrum is best fit by a self-absorbed continuous injection model representing emission coming from the jets, while the higher frequencies show clear signs of an advection dominated accretion flow. We derive a black hole mass and accretion rate consistent with independent measurements. We conclude that the age of the jets is much younger than the innermost cavities, marking the start of a new feedback cycle. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.13804v1-abstract-full').style.display = 'none'; document.getElementById('2010.13804v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">accepted for publication in ApJ; 15 pages; 4 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/2006.09254">arXiv:2006.09254</a> <span> [<a href="https://arxiv.org/pdf/2006.09254">pdf</a>, <a href="https://arxiv.org/format/2006.09254">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/10.1051/0004-6361/201937207">10.1051/0004-6361/201937207 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Radio and X-ray connection in radio mini-halos: implications for hadronic models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ignesti%2C+A">Alessandro Ignesti</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">Gianfranco Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Gitti%2C+M">Myriam Gitti</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</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="2006.09254v1-abstract-short" style="display: inline;"> The radio mini halos (MH) observed in relaxed clusters probe the presence of relativistic particles on scales of hundreds of kpc, beyond the scales directly influenced by the central AGN, but the nature of the mechanism that produces the relativistic electrons is still debated. In this work we explore the connection between thermal and non-thermal components of the ICM in a sample of MH and we stu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.09254v1-abstract-full').style.display = 'inline'; document.getElementById('2006.09254v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.09254v1-abstract-full" style="display: none;"> The radio mini halos (MH) observed in relaxed clusters probe the presence of relativistic particles on scales of hundreds of kpc, beyond the scales directly influenced by the central AGN, but the nature of the mechanism that produces the relativistic electrons is still debated. In this work we explore the connection between thermal and non-thermal components of the ICM in a sample of MH and we study its implications for hadronic models for the origin of the relativistic electrons. We studied the thermal and non-thermal connection by carrying out a point-to-point comparison of the radio and the X-ray surface brightness. We extended the method generally applied to giant radio halos by considering the effects of a grid randomly generated through a Monte Carlo chain. Contrary to what is generally observed for giant radio halos, we find that the mini-halos in our sample have super-linear scaling between radio and X-rays, which suggests a peaked distribution of relativistic electrons and magnetic field. We used the radio and X-ray correlation to constrain the physical parameters of a hadronic model and we compared the model predictions with current observations. Specifically, we focus on a model where cosmic rays are injected by the central AGN and they generate secondaries in the ICM, and we assume that the role of turbulent re-acceleration is negligible. This model allows us to constrain the AGN cosmic ray luminosity in the range $\sim10^{44-46}$ erg s$^{-1}$ and the central magnetic field in the range 10-40 $渭$G. The resulting $纬$-ray fluxes calculated assuming these model parameters do not violate the upper limits on $纬$-ray diffuse emission set by the Fermi-LAT telescope. Further studies are now required to explore the consistency of these large magnetic fields with Faraday rotation studies and to study the interplay between the secondary electrons and the ICM turbulence. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.09254v1-abstract-full').style.display = 'none'; document.getElementById('2006.09254v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 13 figures. Accepted for publication on 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 640, A37 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2005.12950">arXiv:2005.12950</a> <span> [<a href="https://arxiv.org/pdf/2005.12950">pdf</a>, <a href="https://arxiv.org/format/2005.12950">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/staa1506">10.1093/mnras/staa1506 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evidence of AGN feedback and sloshing in the X-ray luminous NGC 1550 galaxy group </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kolokythas%2C+K">Konstantinos Kolokythas</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Worrall%2C+D+M">Diana M. Worrall</a>, <a href="/search/astro-ph?searchtype=author&query=Birkinshaw%2C+M">Mark Birkinshaw</a>, <a href="/search/astro-ph?searchtype=author&query=Raychaudhury%2C+S">Somak Raychaudhury</a>, <a href="/search/astro-ph?searchtype=author&query=Horellou%2C+C">Cathy Horellou</a>, <a href="/search/astro-ph?searchtype=author&query=Intema%2C+H">Huib Intema</a>, <a href="/search/astro-ph?searchtype=author&query=Loubser%2C+I">Ilani Loubser</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="2005.12950v1-abstract-short" style="display: inline;"> We present results from GMRT and Chandra observations of the NGC 1550 galaxy group. Although previously thought of as relaxed, we show evidence that gas sloshing and active galactic nucleus (AGN) heating have affected the structure of the system. The 610 and 235 MHz radio images show an asymmetric jet-lobe structure with a total size of $\sim$33 kpc, with a sharp kink at the base of the more exten… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.12950v1-abstract-full').style.display = 'inline'; document.getElementById('2005.12950v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2005.12950v1-abstract-full" style="display: none;"> We present results from GMRT and Chandra observations of the NGC 1550 galaxy group. Although previously thought of as relaxed, we show evidence that gas sloshing and active galactic nucleus (AGN) heating have affected the structure of the system. The 610 and 235 MHz radio images show an asymmetric jet-lobe structure with a total size of $\sim$33 kpc, with a sharp kink at the base of the more extended western jet, and bending of the shorter eastern jet as it enters the lobe. The 235$-$610 MHz spectral index map shows that both radio lobes have steep spectral indices ($伪_{235}^{610}\geq-1.5$) indicating the presence of an old electron population. The X-ray images reveal an asymmetric structure in the hot gas correlated with the radio structure, as well as potential cavities coincident with the radio lobes, with rims and arms of gas that may have been uplifted by the cavity expansion. The X-ray residual map reveals an arc shaped structure to the east that resembles a sloshing cold front. Radio spectral analysis suggests a radiative age of about 33 Myr for the source, comparable to the sloshing timescale and dynamical estimates of the age of the lobes. An estimate of the mechanical energy required to inflate the cavities suggests that the AGN of NGC 1550 is capable of balancing radiative losses from the intragroup medium (IGM) and preventing excessive cooling, providing that the AGN jets are efficiently coupled to the IGM gas. In conclusion, we find evidence of sloshing motions from both radio and X-ray structures, suggesting that NGC 1550 was perturbed by a minor merger or infalling galaxy about 33 Myr ago. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.12950v1-abstract-full').style.display = 'none'; document.getElementById('2005.12950v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in MNRAS, 17 pages with 13 figures and 10 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/2004.01717">arXiv:2004.01717</a> <span> [<a href="https://arxiv.org/pdf/2004.01717">pdf</a>, <a href="https://arxiv.org/format/2004.01717">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/ab879c">10.3847/1538-4357/ab879c <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Atacama Compact Array Measurements of the Molecular Mass in the NGC 5044 Cooling Flow Group </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schellenberger%2C+G">Gerrit Schellenberger</a>, <a href="/search/astro-ph?searchtype=author&query=David%2C+L+P">Laurence P. David</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+J">Jan Vrtilek</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Lim%2C+J">Jeremy Lim</a>, <a href="/search/astro-ph?searchtype=author&query=Forman%2C+W">William Forman</a>, <a href="/search/astro-ph?searchtype=author&query=Sun%2C+M">Ming Sun</a>, <a href="/search/astro-ph?searchtype=author&query=Combes%2C+F">Francoise Combes</a>, <a href="/search/astro-ph?searchtype=author&query=Salome%2C+P">Philippe Salome</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+C">Christine Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Edge%2C+A">Alastair Edge</a>, <a href="/search/astro-ph?searchtype=author&query=Gastaldello%2C+F">Fabio Gastaldello</a>, <a href="/search/astro-ph?searchtype=author&query=Temi%2C+P">Pasquale Temi</a>, <a href="/search/astro-ph?searchtype=author&query=Brighenti%2C+F">Fabrizio Brighenti</a>, <a href="/search/astro-ph?searchtype=author&query=Bardelli%2C+S">Sandro Bardelli</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="2004.01717v1-abstract-short" style="display: inline;"> The fate of cooling gas in the centers of galaxy clusters and groups is still not well understood, as is also the case for the complex processes of triggering star formation in central dominant galaxies (CDGs), re-heating of cooled gas by AGN, and the triggering/feeding of supermassive black hole outbursts. We present CO observations of the early type galaxy NGC 5044, which resides at the center o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.01717v1-abstract-full').style.display = 'inline'; document.getElementById('2004.01717v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.01717v1-abstract-full" style="display: none;"> The fate of cooling gas in the centers of galaxy clusters and groups is still not well understood, as is also the case for the complex processes of triggering star formation in central dominant galaxies (CDGs), re-heating of cooled gas by AGN, and the triggering/feeding of supermassive black hole outbursts. We present CO observations of the early type galaxy NGC 5044, which resides at the center of an X-ray bright group with a moderate cooling flow. For our analysis we combine CO(2-1) data from the 7m antennae of the Atacama Compact Array (ACA), and the ACA total power array (TP). We demonstrate, using the 7m array data, that we can recover the total flux inferred from IRAM 30m single dish observations, which corresponds to a total molecular mass of about 4x10^7 Msun. Most of the recovered flux is blueshifted with respect to the galaxy rest frame and is extended on kpc-scales, suggesting low filling factor dispersed clouds. We find 8 concentrations of molecular gas out to a radius of 10 arcsec (1.5 kpc), which we identify with giant molecular clouds. The total molecular gas mass is more centrally concentrated than the X-ray emitting gas, but extended in the north-east/south-west direction beyond the IRAM 30m beam. We also compare the spatial extent of the molecular gas to the Halpha emission: The CO emission coincides with the very bright Halpha region in the center. We do not detect CO emission in the fainter Halpha regions. Furthermore, we find two CO absorption features spatially located at the center of the galaxy, within 5 pc projected distance of the AGN, infalling at 255 and 265 km/s relative to the AGN. This indicates that the two giant molecular clouds seen in absorption are most likely within the sphere of influence of the supermassive black hole. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.01717v1-abstract-full').style.display = 'none'; document.getElementById('2004.01717v1-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 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 16 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/2002.01291">arXiv:2002.01291</a> <span> [<a href="https://arxiv.org/pdf/2002.01291">pdf</a>, <a href="https://arxiv.org/format/2002.01291">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab6a9d">10.3847/1538-4357/ab6a9d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discovery of a giant radio fossil in the Ophiuchus galaxy cluster </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Markevitch%2C+M">M. Markevitch</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston-Hollitt%2C+M">M. Johnston-Hollitt</a>, <a href="/search/astro-ph?searchtype=author&query=Wik%2C+D+R">D. R. Wik</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+Q+H+S">Q. H. S. Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T+E">T. E. Clarke</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="2002.01291v1-abstract-short" style="display: inline;"> The Ophiuchus galaxy cluster exhibits a curious concave gas density discontinuity at the edge of its cool core. It was discovered in the Chandra X-ray image by Werner and collaborators, who considered a possibility of it being a boundary of an AGN-inflated bubble located outside the core, but discounted this possibility because it required much too powerful an AGN outburst. Using low-frequency (72… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.01291v1-abstract-full').style.display = 'inline'; document.getElementById('2002.01291v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.01291v1-abstract-full" style="display: none;"> The Ophiuchus galaxy cluster exhibits a curious concave gas density discontinuity at the edge of its cool core. It was discovered in the Chandra X-ray image by Werner and collaborators, who considered a possibility of it being a boundary of an AGN-inflated bubble located outside the core, but discounted this possibility because it required much too powerful an AGN outburst. Using low-frequency (72-240 MHz) radio data from MWA GLEAM and GMRT, we found that the X-ray structure is, in fact, a giant cavity in the X-ray gas filled with diffuse radio emission with an extraordinarily steep radio spectrum. It thus appears to be a very aged fossil of the most powerful AGN outburst seen in any galaxy cluster ($pV\sim 5\times 10^{61}$ erg for this cavity). There is no apparent diametrically opposite counterpart either in X-ray or in the radio. It may have aged out of the observable radio band because of the cluster asymmetry. At present, the central AGN exhibits only a weak radio source, so it should have been much more powerful in the past to have produced such a bubble. The AGN is currently starved of accreting cool gas because the gas density peak is displaced by core sloshing. The sloshing itself could have been set off by this extraordinary explosion if it had occurred in an asymmetric gas core. This dinosaur may be an early example of a new class of sources to be uncovered by low-frequency surveys of galaxy clusters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.01291v1-abstract-full').style.display = 'none'; document.getElementById('2002.01291v1-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 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 12 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.09200">arXiv:1908.09200</a> <span> [<a href="https://arxiv.org/pdf/1908.09200">pdf</a>, <a href="https://arxiv.org/format/1908.09200">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </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/ab6d70">10.3847/1538-4357/ab6d70 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Pressure profiles and mass estimates using high-resolution Sunyaev-Zel'dovich effect observations of Zwicky 3146 with MUSTANG-2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Romero%2C+C+E">Charles E. Romero</a>, <a href="/search/astro-ph?searchtype=author&query=Sievers%2C+J">Jonathan Sievers</a>, <a href="/search/astro-ph?searchtype=author&query=Ghirardini%2C+V">Vittorio Ghirardini</a>, <a href="/search/astro-ph?searchtype=author&query=Dicker%2C+S">Simon Dicker</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Mroczkowski%2C+T">Tony Mroczkowski</a>, <a href="/search/astro-ph?searchtype=author&query=Mason%2C+B+S">Brian S. Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Sarazin%2C+C">Craig Sarazin</a>, <a href="/search/astro-ph?searchtype=author&query=Devlin%2C+M">Mark Devlin</a>, <a href="/search/astro-ph?searchtype=author&query=Gaspari%2C+M">Massimo Gaspari</a>, <a href="/search/astro-ph?searchtype=author&query=Battaglia%2C+N">Nicholas Battaglia</a>, <a href="/search/astro-ph?searchtype=author&query=Hilton%2C+M">Matthew Hilton</a>, <a href="/search/astro-ph?searchtype=author&query=Bulbul%2C+E">Esra Bulbul</a>, <a href="/search/astro-ph?searchtype=author&query=Lowe%2C+I">Ian Lowe</a>, <a href="/search/astro-ph?searchtype=author&query=Stanchfield%2C+S">Sara Stanchfield</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="1908.09200v1-abstract-short" style="display: inline;"> The galaxy cluster Zwicky 3146 is a sloshing cool core cluster at $z=0.291$ that in X-ray imaging does not appear to exhibit significant pressure substructure in the intracluster medium (ICM). The published $M_{500}$ values range between $3.88^{+0.62}_{-0.58}$ to $22.50 \pm 7.58 \times 10^{14}$ M$_{\odot}$, where ICM-based estimates with reported errors $<20$\% suggest that we should expect to fin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.09200v1-abstract-full').style.display = 'inline'; document.getElementById('1908.09200v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.09200v1-abstract-full" style="display: none;"> The galaxy cluster Zwicky 3146 is a sloshing cool core cluster at $z=0.291$ that in X-ray imaging does not appear to exhibit significant pressure substructure in the intracluster medium (ICM). The published $M_{500}$ values range between $3.88^{+0.62}_{-0.58}$ to $22.50 \pm 7.58 \times 10^{14}$ M$_{\odot}$, where ICM-based estimates with reported errors $<20$\% suggest that we should expect to find a mass between $6.53^{+0.44}_{-0.44} \times 10^{14}$ M$_{\odot}$ (from Planck, with an $8.4蟽$ detection) and $8.52^{+1.77}_{-1.47} \times 10^{14}$ M$_{\odot}$ (from ACT, with a $14蟽$ detection). This broad range of masses is suggestive that there is ample room for improvement for all methods. Here, we investigate the ability to estimate the mass of Zwicky 3146 via the Sunyaev-Zel'dovich (SZ) effect with data taken at 90 GHz by MUSTANG-2 to a noise level better than $15\ 渭$K at the center, and a cluster detection of $104蟽$. We derive a pressure profile from our SZ data which is in excellent agreement with that derived from X-ray data. From our SZ-derived pressure profiles, we infer $M_{500}$ and $M_{2500}$ via three methods -- $Y$-$M$ scaling relations, the virial theorem, and hydrostatic equilibrium -- where we employ X-ray constraints from \emph{XMM-Newton} on the electron density profile when assuming hydrostatic equilibrium. Depending on the model and estimation method, our $M_{500}$ estimates range from $6.23 \pm 0.59$ to $10.6 \pm 0.95 \times 10^{14}$ M$_{\odot}$, where our estimate from hydrostatic equilibrium, is $8.29^{+1.93}_{-1.24}$ ($\pm 19.1$\% stat) ${}^{+0.74}_{-0.68}$ ($\pm 8.6$\% sys, calibration) $\times 10^{14}$ M$_{\odot}$. Our fiducial mass, derived from a $Y$-$M$ relation is $8.16^{+0.44}_{-0.54}$ ($\pm 5.5$\% stat) ${}^{+0.46}_{-0.43}$ ($\pm 5.5$\% sys, $Y$-$M$) ${}^{+0.59}_{-0.55}$ ($\pm 7.0$\% sys, cal.) $\times 10^{14}$ M$_{\odot}$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.09200v1-abstract-full').style.display = 'none'; document.getElementById('1908.09200v1-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 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 16 figures; submitted to ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2020 ApJ, 891, 90 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.10768">arXiv:1907.10768</a> <span> [<a href="https://arxiv.org/pdf/1907.10768">pdf</a>, <a href="https://arxiv.org/format/1907.10768">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/stz2082">10.1093/mnras/stz2082 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Complete Local Volume Groups Sample -- III. Characteristics of group central radio galaxies in the Local Universe </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kolokythas%2C+K">Konstantinos Kolokythas</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Intema%2C+H">Huib Intema</a>, <a href="/search/astro-ph?searchtype=author&query=Raychaudhury%2C+S">Somak Raychaudhury</a>, <a href="/search/astro-ph?searchtype=author&query=Babul%2C+A">Arif Babul</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Gitti%2C+M">Myriam Gitti</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="1907.10768v2-abstract-short" style="display: inline;"> Using new 610 MHz and 235 MHz observations from the Giant Metrewave Radio Telescope (GMRT) in combination with archival GMRT and Very Large Array (VLA) survey data we present the radio properties of the dominant early-type galaxies in the low$-$richness sub-sample of the Complete Local-volume Groups Sample (CLoGS; 27 galaxy groups) and provide results for the radio properties of the full CLoGS sam… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.10768v2-abstract-full').style.display = 'inline'; document.getElementById('1907.10768v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.10768v2-abstract-full" style="display: none;"> Using new 610 MHz and 235 MHz observations from the Giant Metrewave Radio Telescope (GMRT) in combination with archival GMRT and Very Large Array (VLA) survey data we present the radio properties of the dominant early-type galaxies in the low$-$richness sub-sample of the Complete Local-volume Groups Sample (CLoGS; 27 galaxy groups) and provide results for the radio properties of the full CLoGS sample for the first time. We find a high radio detection rate in the dominant galaxies of the low-richness sub-sample of 82% (22/27); for the full CLoGS sample, the detection rate is 87% (46/53). The group-dominant galaxies exhibit a wide range of radio power, 10$^{20}$ $-$ 10$^{25}$ W Hz$^{-1}$ in the 235 and 610 MHz bands, with the majority (53%) presenting point-like radio emission, 19% hosting currently active radio jets, 6% having remnant jets, 9% being diffuse and 13% having no detected radio emission. The mean spectral index of the detected radio sources in the 235$-$610 MHz frequency range is found to be $伪_{235}^{610}\sim$0.68, and $伪_{235}^{1400}\sim$0.59 in the 235$-$1400 MHz one. In agreement with earlier studies, we find that the fraction of ultra-steep spectrum sources ($伪>$1.3) is $\sim$4%, mostly dependent on the detection limit at 235 MHz. The majority of point-like systems are found to reside in dynamically young groups, whereas jet systems show no preference between spiral-rich and spiral-poor group environments. The mechanical power of the jet sources in the low$-$richness sample groups is estimated to be $\sim$10$^{42}$ $-$ 10$^{44}$ erg s$^{-1}$ with their black hole masses ranging between 2$\times$10$^{8}$ $-$ 5$\times$10$^{9}$ M$_{\odot}$. We confirm previous findings that, while radio jet sources tend to be associated with more massive black holes, black hole mass is not the decisive factor in determining jet activity or power. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.10768v2-abstract-full').style.display = 'none'; document.getElementById('1907.10768v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in MNRAS, 48 pages of which 18 Manuscript pages with 10 tables and 8 figures, plus 30 pages of appendices with 25 figures and 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.01981">arXiv:1907.01981</a> <span> [<a href="https://arxiv.org/pdf/1907.01981">pdf</a>, <a href="https://arxiv.org/format/1907.01981">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="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1538-3873/ab63eb">10.1088/1538-3873/ab63eb <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Karl G. Jansky Very Large Array Sky Survey (VLASS). Science case and survey design </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lacy%2C+M">M. Lacy</a>, <a href="/search/astro-ph?searchtype=author&query=Baum%2C+S+A">S. A. Baum</a>, <a href="/search/astro-ph?searchtype=author&query=Chandler%2C+C+J">C. J. Chandler</a>, <a href="/search/astro-ph?searchtype=author&query=Chatterjee%2C+S">S. Chatterjee</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T+E">T. E. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Deustua%2C+S">S. Deustua</a>, <a href="/search/astro-ph?searchtype=author&query=English%2C+J">J. English</a>, <a href="/search/astro-ph?searchtype=author&query=Farnes%2C+J">J. Farnes</a>, <a href="/search/astro-ph?searchtype=author&query=Gaensler%2C+B+M">B. M. Gaensler</a>, <a href="/search/astro-ph?searchtype=author&query=Gugliucci%2C+N">N. Gugliucci</a>, <a href="/search/astro-ph?searchtype=author&query=Hallinan%2C+G">G. Hallinan</a>, <a href="/search/astro-ph?searchtype=author&query=Kent%2C+B+R">B. R. Kent</a>, <a href="/search/astro-ph?searchtype=author&query=Kimball%2C+A">A. Kimball</a>, <a href="/search/astro-ph?searchtype=author&query=Law%2C+C+J">C. J. Law</a>, <a href="/search/astro-ph?searchtype=author&query=Lazio%2C+T+J+W">T. J. W. Lazio</a>, <a href="/search/astro-ph?searchtype=author&query=Marvil%2C+J">J. Marvil</a>, <a href="/search/astro-ph?searchtype=author&query=Mao%2C+S+A">S. A. Mao</a>, <a href="/search/astro-ph?searchtype=author&query=Medlin%2C+D">D. Medlin</a>, <a href="/search/astro-ph?searchtype=author&query=Mooley%2C+K">K. Mooley</a>, <a href="/search/astro-ph?searchtype=author&query=Murphy%2C+E+J">E. J. Murphy</a>, <a href="/search/astro-ph?searchtype=author&query=Myers%2C+S">S. Myers</a>, <a href="/search/astro-ph?searchtype=author&query=Osten%2C+R">R. Osten</a>, <a href="/search/astro-ph?searchtype=author&query=Richards%2C+G+T">G. T. Richards</a>, <a href="/search/astro-ph?searchtype=author&query=Rosolowsky%2C+E">E. Rosolowsky</a>, <a href="/search/astro-ph?searchtype=author&query=Rudnick%2C+L">L. Rudnick</a> , et al. (53 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="1907.01981v3-abstract-short" style="display: inline;"> The Very Large Array Sky Survey (VLASS) is a synoptic, all-sky radio sky survey with a unique combination of high angular resolution ($\approx$2.5"), sensitivity (a 1$蟽$ goal of 70 $渭$Jy/beam in the coadded data), full linear Stokes polarimetry, time domain coverage, and wide bandwidth (2-4 GHz). The first observations began in September 2017, and observing for the survey will finish in 2024. VLAS… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.01981v3-abstract-full').style.display = 'inline'; document.getElementById('1907.01981v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.01981v3-abstract-full" style="display: none;"> The Very Large Array Sky Survey (VLASS) is a synoptic, all-sky radio sky survey with a unique combination of high angular resolution ($\approx$2.5"), sensitivity (a 1$蟽$ goal of 70 $渭$Jy/beam in the coadded data), full linear Stokes polarimetry, time domain coverage, and wide bandwidth (2-4 GHz). The first observations began in September 2017, and observing for the survey will finish in 2024. VLASS will use approximately 5500 hours of time on the Karl G. Jansky Very Large Array (VLA) to cover the whole sky visible to the VLA (Declination $>-40^{\circ}$), a total of 33,885 deg$^2$. The data will be taken in three epochs to allow the discovery of variable and transient radio sources. The survey is designed to engage radio astronomy experts, multi-wavelength astronomers, and citizen scientists alike. By utilizing an "on the fly" interferometry mode, the observing overheads are much reduced compared to a conventional pointed survey. In this paper, we present the science case and observational strategy for the survey, and also results from early survey observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.01981v3-abstract-full').style.display = 'none'; document.getElementById('1907.01981v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">34 pages, accepted by PASP (modified from prior version to address referee's and coauthor comments). (v2) Minor fixes to author list</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.07087">arXiv:1906.07087</a> <span> [<a href="https://arxiv.org/pdf/1906.07087">pdf</a>, <a href="https://arxiv.org/ps/1906.07087">ps</a>, <a href="https://arxiv.org/format/1906.07087">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab29f1">10.3847/1538-4357/ab29f1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Expanding the sample of radio minihalos in galaxy clusters </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Markevitch%2C+M">Maxim Markevitch</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">Rossella Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">Tiziana Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T+E">Tracy E. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Kale%2C+R">Ruta Kale</a>, <a href="/search/astro-ph?searchtype=author&query=Cuciti%2C+V">Virginia Cuciti</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="1906.07087v1-abstract-short" style="display: inline;"> Radio minihalos are diffuse synchrotron sources of unknown origin found in the cool cores of some galaxy clusters. We use GMRT and VLA data to expand the sample of minihalos by reporting three new minihalo detections (A 2667, A 907 and PSZ1 G139.61+24.20) and confirming minihalos in five clusters (MACS J0159.8-0849, MACS J0329.6-0211, RXC J2129.6+0005, AS 780 and A 3444). With these new detections… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.07087v1-abstract-full').style.display = 'inline'; document.getElementById('1906.07087v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.07087v1-abstract-full" style="display: none;"> Radio minihalos are diffuse synchrotron sources of unknown origin found in the cool cores of some galaxy clusters. We use GMRT and VLA data to expand the sample of minihalos by reporting three new minihalo detections (A 2667, A 907 and PSZ1 G139.61+24.20) and confirming minihalos in five clusters (MACS J0159.8-0849, MACS J0329.6-0211, RXC J2129.6+0005, AS 780 and A 3444). With these new detections and confirmations, the sample now stands at 23, the largest sample to date. For consistency, we also reanalyze archival VLA 1.4 GHz observations of 7 known minihalos. We revisit possible correlations between the non-thermal emission and the thermal properties of their cluster hosts. Consistently with our earlier findings from a smaller sample, we find no strong relation between the minihalo radio luminosity and the total cluster mass. Instead, we find a strong positive correlation between the minihalo radio power and X-ray bolometric luminosity of the cool core (r<70 kpc). This supplements our earlier result that most if not all cool cores in massive clusters contain a minihalo. Comparison of radio and Chandra X-ray images indicates that the minihalo emission is typically confined by concentric sloshing cold fronts in the cores of most of our clusters, supporting the hypothesis that minihalos arise from electron reacceleration by turbulence caused by core gas sloshing. Taken together, our findings suggest that the origin of minihalos should be closely related to the properties of thermal plasma in cluster cool cores. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.07087v1-abstract-full').style.display = 'none'; document.getElementById('1906.07087v1-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 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">37 pages, 16 figures, 8 tables, accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.10660">arXiv:1903.10660</a> <span> [<a href="https://arxiv.org/pdf/1903.10660">pdf</a>, <a href="https://arxiv.org/format/1903.10660">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/ab3e03">10.3847/1538-4357/ab3e03 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Radio follow-up of a candidate gamma-ray transient in the sky localization area of GW170608 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Artkop%2C+K">Kyle Artkop</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+R">Rachel Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Corsi%2C+A">Alessandra Corsi</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Peters%2C+W+M">Wendy M. Peters</a>, <a href="/search/astro-ph?searchtype=author&query=Perna%2C+R">Rosalba Perna</a>, <a href="/search/astro-ph?searchtype=author&query=Cenko%2C+S+B">S. Bradley Cenko</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T+E">Tracy E. Clarke</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="1903.10660v2-abstract-short" style="display: inline;"> After the identification of a candidate $纬$-ray transient in the error region of the binary black hole (BBH) merger GW150914 by the \textit{Fermi} satellite, the question of whether BBH mergers can be associated to electromagnetic counterparts remains highly debated. Here, we present radio follow-up observations of GW170608, a BBH merger that occurred during the second observing run (O2) of the Ad… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.10660v2-abstract-full').style.display = 'inline'; document.getElementById('1903.10660v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.10660v2-abstract-full" style="display: none;"> After the identification of a candidate $纬$-ray transient in the error region of the binary black hole (BBH) merger GW150914 by the \textit{Fermi} satellite, the question of whether BBH mergers can be associated to electromagnetic counterparts remains highly debated. Here, we present radio follow-up observations of GW170608, a BBH merger that occurred during the second observing run (O2) of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO). Our radio follow up focused on a specific field contained in the GW170608 sky localization area, where a candidate high-energy transient was detected by the \textit{Fermi} Large Area Telescope (LAT). We make use of data collected at 1.4\,GHz with the Karl G. Jansky Very Large Array (VLA), as well as with the VLA Low-band Ionosphere and Transient Experiment (VLITE). Our analysis is sensitive to potential radio afterglows with luminosity densities $L_{\rm 1.4\,GHz}\gtrsim 6\times10^{28}$\,erg\,s$^{-1}$\,Hz$^{-1}$. In the most optimistic theoretical models, $\approx 20\%$ of BBH events occurring in massive hosts could be associated with outflows as radio luminous as this. Although we find no evidence for the presence of a radio counterpart associated with the LAT candidate in the GW170608 error region, our analysis demonstrates the feasibility of future radio follow-up observations of well localized BBHs. Comparing our radio upper-limits with theoretical expectations for the radio afterglows potentially associated with jets launched in BBH mergers, we find that for jets of energy $\approx 10^{49}$\,erg seen on-axis, only jet angles $胃_{jet}\gtrsim 40^{\circ}$ are compatible with the observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.10660v2-abstract-full').style.display = 'none'; document.getElementById('1903.10660v2-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 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 1 figure, 3 tables; version update to match the published one</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.08044">arXiv:1903.08044</a> <span> [<a href="https://arxiv.org/pdf/1903.08044">pdf</a>, <a href="https://arxiv.org/format/1903.08044">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/ab100b">10.3847/1538-4357/ab100b <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Extended Radio Structures and a Compact X-ray Cool-Core in the Cluster Source PKS 1353-341 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+C+C">C. C. Cheung</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T+E">T. E. Clarke</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="1903.08044v1-abstract-short" style="display: inline;"> We present a radio and X-ray study of PKS 1353-341, the brightest cluster galaxy radio source at the center of a recent Chandra-discovered X-ray cluster. Our multi-frequency VLA images reveal an edge-brightened (FR-II), double-lobed structure with total ~50 kpc extent and 1.5 GHz power of $1.2\times10^{25}$ W Hz$^{-1}$, separated from the bright, arcsecond-scale core. We reanalyzed the Chandra dat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.08044v1-abstract-full').style.display = 'inline'; document.getElementById('1903.08044v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.08044v1-abstract-full" style="display: none;"> We present a radio and X-ray study of PKS 1353-341, the brightest cluster galaxy radio source at the center of a recent Chandra-discovered X-ray cluster. Our multi-frequency VLA images reveal an edge-brightened (FR-II), double-lobed structure with total ~50 kpc extent and 1.5 GHz power of $1.2\times10^{25}$ W Hz$^{-1}$, separated from the bright, arcsecond-scale core. We reanalyzed the Chandra data and found the X-ray emitting AGN is offset by ~9 kpc from a compact X-ray cool-core with temperature, $kT=3.1\pm0.5$ keV, and a radius of ~22 kpc, surrounded by a hotter $kT=6.3\pm0.7$ keV gas out to ~50 kpc. The offset suggests sloshing inside the cool-core induced by a minor merger or a past outburst of the AGN that produced the large-scale radio lobes. The comparable spatial scales of the lobes with the interface between the different temperature X-ray plasma indicate the lobes are actively heating the outer layers of what is now a remnant compact cool-core. Our dual-frequency VLBA images reveal substructure in the central radio source, consisting of a radio core with double-sided pc-scale jets pointing toward the kpc-scale structures. The northern jet is detected only at 8.4 GHz, indicating its emission is behind an absorbing torus or disk. We also measured faster apparent motions in the southern jet up to $1.9\pm1.1c$ than in the northern jet ($0.8\pm0.5c$). While the VLBA observations indicate the southern jet is aligned slightly closer to our line of sight, the asymmetries are overall modest and imply minimal projection effects in the large-scale radio structures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.08044v1-abstract-full').style.display = 'none'; document.getElementById('1903.08044v1-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 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, ApJ accepted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.06356">arXiv:1903.06356</a> <span> [<a href="https://arxiv.org/pdf/1903.06356">pdf</a>, <a href="https://arxiv.org/format/1903.06356">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"> Physics of cosmic plasmas from high angular resolution X-ray imaging of galaxy clusters </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Markevitch%2C+M">Maxim Markevitch</a>, <a href="/search/astro-ph?searchtype=author&query=Bulbul%2C+E">Esra Bulbul</a>, <a href="/search/astro-ph?searchtype=author&query=Churazov%2C+E">Eugene Churazov</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Kraft%2C+R">Ralph Kraft</a>, <a href="/search/astro-ph?searchtype=author&query=Kunz%2C+M">Matthew Kunz</a>, <a href="/search/astro-ph?searchtype=author&query=Nagai%2C+D">Daisuke Nagai</a>, <a href="/search/astro-ph?searchtype=author&query=Roediger%2C+E">Elke Roediger</a>, <a href="/search/astro-ph?searchtype=author&query=Ruszkowski%2C+M">Mateusz Ruszkowski</a>, <a href="/search/astro-ph?searchtype=author&query=Schekochihin%2C+A">Alex Schekochihin</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R">Reinout van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Vikhlinin%2C+A">Alexey Vikhlinin</a>, <a href="/search/astro-ph?searchtype=author&query=Walker%2C+S+A">Stephen A. Walker</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+Q+H+S">Qian H. S. Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Werner%2C+N">Norbert Werner</a>, <a href="/search/astro-ph?searchtype=author&query=Wik%2C+D">Daniel Wik</a>, <a href="/search/astro-ph?searchtype=author&query=Zhuravleva%2C+I">Irina Zhuravleva</a>, <a href="/search/astro-ph?searchtype=author&query=ZuHone%2C+J">John ZuHone</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="1903.06356v1-abstract-short" style="display: inline;"> Galaxy clusters are massive dark matter-dominated systems filled with X-ray emitting, optically thin plasma. Their large size and relative simplicity (at least as astrophysical objects go) make them a unique laboratory to measure some of the interesting plasma properties that are inaccessible by other means but fundamentally important for understanding and modeling many astrophysical phenomena --… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.06356v1-abstract-full').style.display = 'inline'; document.getElementById('1903.06356v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.06356v1-abstract-full" style="display: none;"> Galaxy clusters are massive dark matter-dominated systems filled with X-ray emitting, optically thin plasma. Their large size and relative simplicity (at least as astrophysical objects go) make them a unique laboratory to measure some of the interesting plasma properties that are inaccessible by other means but fundamentally important for understanding and modeling many astrophysical phenomena -- from solar flares to black hole accretion to galaxy formation and the emergence of the cosmological Large Scale Structure. While every cluster astrophysicist is eagerly anticipating the direct gas velocity measurements from the forthcoming microcalorimeters onboard XRISM, Athena and future missions such as Lynx, a number of those plasma properties can best be probed by high-resolution X-ray imaging of galaxy clusters. Chandra has obtained some trailblazing results, but only grazed the surface of such studies. In this white paper, we discuss why we need arcsecond-resolution, high collecting area, low relative background X-ray imagers (with modest spectral resolution), such as the proposed AXIS and the imaging detector of Lynx. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.06356v1-abstract-full').style.display = 'none'; document.getElementById('1903.06356v1-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 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Science white paper submitted for Astro2020 Decadal survey. 9 pages, 4 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/1811.08430">arXiv:1811.08430</a> <span> [<a href="https://arxiv.org/pdf/1811.08430">pdf</a>, <a href="https://arxiv.org/format/1811.08430">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201833992">10.1051/0004-6361/201833992 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ultra-steep spectrum emission in the merging galaxy cluster Abell 1914 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">S. Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Intema%2C+H+T">H. T. Intema</a>, <a href="/search/astro-ph?searchtype=author&query=Shimwell%2C+T+W">T. W. Shimwell</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R+J">R. J. van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Botteon%2C+A">A. Botteon</a>, <a href="/search/astro-ph?searchtype=author&query=R%C3%B6ttgering%2C+H+J+A">H. J. A. R枚ttgering</a>, <a href="/search/astro-ph?searchtype=author&query=Hoang%2C+D+N">D. N. Hoang</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">G. Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=de+Gasperin%2C+F">F. de Gasperin</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Hoekstra%2C+H">H. Hoekstra</a>, <a href="/search/astro-ph?searchtype=author&query=Stroe%2C+A">A. Stroe</a>, <a href="/search/astro-ph?searchtype=author&query=Br%C3%BCggen%2C+M">M. Br眉ggen</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">R. Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Shulevski%2C+A">A. Shulevski</a>, <a href="/search/astro-ph?searchtype=author&query=Drabent%2C+A">A. Drabent</a>, <a href="/search/astro-ph?searchtype=author&query=Rafferty%2C+D">D. Rafferty</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="1811.08430v1-abstract-short" style="display: inline;"> A number of radio observations have revealed the presence of large synchrotron-emitting sources associated with the intra-cluster medium. There is strong observational evidence that the emitting particles have been (re-)accelerated by shocks and turbulence generated during merger events. The particles that are accelerated are thought to have higher initial energies than those in the thermal pool b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.08430v1-abstract-full').style.display = 'inline'; document.getElementById('1811.08430v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.08430v1-abstract-full" style="display: none;"> A number of radio observations have revealed the presence of large synchrotron-emitting sources associated with the intra-cluster medium. There is strong observational evidence that the emitting particles have been (re-)accelerated by shocks and turbulence generated during merger events. The particles that are accelerated are thought to have higher initial energies than those in the thermal pool but the origin of such mildly relativistic particles remains uncertain and needs to be further investigated. The galaxy cluster Abell 1914 is a massive galaxy cluster in which X-ray observations show clear evidence of merging activity. We carried out radio observations of this cluster with the LOw Frequency ARay (LOFAR) at 150 MHz and the Giant Metrewave Radio Telescope (GMRT) at 610 MHz. We also analysed Very Large Array (VLA) 1.4 GHz data, archival GMRT 325 MHz data, CFHT weak lensing data and Chandra observations. Our analysis shows that the ultra-steep spectrum source (4C38.39; $伪\lesssim -2$), previously thought to be part of a radio halo, is a distinct source with properties that are consistent with revived fossil plasma sources. Finally, we detect some diffuse emission to the west of the source 4C38.39 that could belong to a radio halo. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.08430v1-abstract-full').style.display = 'none'; document.getElementById('1811.08430v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 figures, 2 tables and 12 pages. This paper is part of the LOFAR surveys data release 1 and has been accepted for publication in a special edition of A&A that will appear in Feb 2019, volume 622. The catalogues and images from the data release will be publicly available on lofar-surveys.org upon publication of the 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/1807.11579">arXiv:1807.11579</a> <span> [<a href="https://arxiv.org/pdf/1807.11579">pdf</a>, <a href="https://arxiv.org/ps/1807.11579">ps</a>, <a href="https://arxiv.org/format/1807.11579">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"> Thermal and non-thermal connection in radio mini-halos </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ignesti%2C+A">Alessandro Ignesti</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">Gianfranco Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Gitti%2C+M">Myriam Gitti</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</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="1807.11579v1-abstract-short" style="display: inline;"> Several cool-core clusters are known to host a radio mini-halo, a diffuse, steep-spectrum radio source located in their cores, thus probing the presence of non-thermal components as magnetic field and relativistic particles on scales not directly influenced by the central AGN. The nature of the mechanism that produces a population of radio-emitting relativistic particles on the scale of hundreds o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.11579v1-abstract-full').style.display = 'inline'; document.getElementById('1807.11579v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.11579v1-abstract-full" style="display: none;"> Several cool-core clusters are known to host a radio mini-halo, a diffuse, steep-spectrum radio source located in their cores, thus probing the presence of non-thermal components as magnetic field and relativistic particles on scales not directly influenced by the central AGN. The nature of the mechanism that produces a population of radio-emitting relativistic particles on the scale of hundreds of kiloparsecs is still unclear. At the same time, it is still debated if the central AGN may play a role in the formation of mini-halos by providing the seed of the relativistic particles. We aim to investigate these open issues by studying the connection between thermal and non-thermal components of the intra-cluster medium. We performed a point-to-point analysis of the radio and the X-ray surface brightness of a compilation of mini-halos. We find that mini-halos have super-linear scalings between radio and X-rays, with radio brightness declining more steeply than the X-ray brightness. This trend is opposite to that generally observed in giant radio halos, thus marking a possible difference in the physics of the two radio sources. Finally, using the scalings between radio and X-rays and assuming a hadronic origin of mini-halos we derive constraints on the magnetic field in the core of the hosting clusters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.11579v1-abstract-full').style.display = 'none'; document.getElementById('1807.11579v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Proceedings of the IAU Symposium IAUS342, "Perseus in Sicily: from black hole to cluster outskirts". 4 pages, 2 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/1807.11095">arXiv:1807.11095</a> <span> [<a href="https://arxiv.org/pdf/1807.11095">pdf</a>, <a href="https://arxiv.org/ps/1807.11095">ps</a>, <a href="https://arxiv.org/format/1807.11095">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/sty2030">10.1093/mnras/sty2030 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Complete Local Volume Groups Sample - II. A study of the Central Radio Galaxies in the High$-$Richness Sub-sample </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kolokythas%2C+K">Konstantinos Kolokythas</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Sullivan%2C+E">Ewan O'Sullivan</a>, <a href="/search/astro-ph?searchtype=author&query=Raychaudhury%2C+S">Somak Raychaudhury</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Gitti%2C+M">Myriam Gitti</a>, <a href="/search/astro-ph?searchtype=author&query=Babul%2C+A">Arif Babul</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="1807.11095v1-abstract-short" style="display: inline;"> We present a study of the radio properties of the dominant early-type galaxies in 26 galaxy groups, the high-richness sub-sample of the Complete Local-volume Groups Sample (CLoGS). Combining new 610 MHz and 235 MHz observations of 21 groups from the Giant Metrewave Radio Telescope (GMRT) with archival GMRT and Very Large Array (VLA) survey data, we find a high detection rate, with 92% of the domin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.11095v1-abstract-full').style.display = 'inline'; document.getElementById('1807.11095v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.11095v1-abstract-full" style="display: none;"> We present a study of the radio properties of the dominant early-type galaxies in 26 galaxy groups, the high-richness sub-sample of the Complete Local-volume Groups Sample (CLoGS). Combining new 610 MHz and 235 MHz observations of 21 groups from the Giant Metrewave Radio Telescope (GMRT) with archival GMRT and Very Large Array (VLA) survey data, we find a high detection rate, with 92% of the dominant galaxies hosting radio sources. The sources have a wide range of luminosities, 10$^{20}$ $-$ 10$^{24}$ W/Hz in the 235 and 610 MHz bands. The majority (54%) are point-like, but 23% have radio jets, and another 15% are diffuse radio sources with no clear jet/lobe morphology. The spectral index of the detected radio sources ranges from very flat values of ~0.2 to typical radio synchrotron spectra of ~0.9 with only two presenting steep radio spectra with $伪_{235}^{610}$ > 1. We find that jet sources are more common in X-ray bright groups, with radio non-detections found only in X-ray faint systems. Radio point sources appear in all group environments irrespective of their X-ray properties or spiral fraction. We estimate the mechanical power (Pcav) of the jet sources in the X-ray bright groups to be 10$^{41}$ $-$ 10$^{43}$ erg/s, with the two large-scale jet systems (NGC 193 and NGC 4261) showing jet powers two orders of magnitude greater than the radiative losses from the cool cores of their groups. This suggests that central AGN are not always in balance with cooling, but may instead produce powerful periodical bursts of feedback heating. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.11095v1-abstract-full').style.display = 'none'; document.getElementById('1807.11095v1-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 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication by MNRAS, 19 Manuscript pages with 8 tables and 8 figures, plus 13 pages of appendices</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.06904">arXiv:1807.06904</a> <span> [<a href="https://arxiv.org/pdf/1807.06904">pdf</a>, <a href="https://arxiv.org/format/1807.06904">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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/10.1051/0004-6361/201832801">10.1051/0004-6361/201832801 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Cosmic dance in the Shapley Concentration Core - I. A study of the radio emission of the BCGs and tailed radio galaxies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Di+Gennaro%2C+G">G. Di Gennaro</a>, <a href="/search/astro-ph?searchtype=author&query=Venturi%2C+T">T. Venturi</a>, <a href="/search/astro-ph?searchtype=author&query=Dallacasa%2C+D">D. Dallacasa</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">S. Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Merluzzi%2C+P">P. Merluzzi</a>, <a href="/search/astro-ph?searchtype=author&query=Busarello%2C+G">G. Busarello</a>, <a href="/search/astro-ph?searchtype=author&query=Mercurio%2C+A">A. Mercurio</a>, <a href="/search/astro-ph?searchtype=author&query=Bardelli%2C+S">S. Bardelli</a>, <a href="/search/astro-ph?searchtype=author&query=Gastaldello%2C+F">F. Gastaldello</a>, <a href="/search/astro-ph?searchtype=author&query=Grado%2C+A">A. Grado</a>, <a href="/search/astro-ph?searchtype=author&query=Haines%2C+C+P">C. P. Haines</a>, <a href="/search/astro-ph?searchtype=author&query=Limatola%2C+L">L. Limatola</a>, <a href="/search/astro-ph?searchtype=author&query=Rossetti%2C+M">M. Rossetti</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="1807.06904v1-abstract-short" style="display: inline;"> The Shapley Concentration ($z\approx0.048$) covers several degrees in the Southern Hemisphere, and includes galaxy clusters in advanced evolutionary stage, groups of clusters in the early stages of merger, fairly massive clusters with ongoing accretion activity, and smaller groups located in filaments in the regions between the main clusters. With the goal to investigate the role of cluster merger… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.06904v1-abstract-full').style.display = 'inline'; document.getElementById('1807.06904v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.06904v1-abstract-full" style="display: none;"> The Shapley Concentration ($z\approx0.048$) covers several degrees in the Southern Hemisphere, and includes galaxy clusters in advanced evolutionary stage, groups of clusters in the early stages of merger, fairly massive clusters with ongoing accretion activity, and smaller groups located in filaments in the regions between the main clusters. With the goal to investigate the role of cluster mergers and accretion on the radio galaxy population, we performed a multi-wavelength study of the BCGs and of the galaxies showing extended radio emission in the cluster complexes of Abell 3528 and Abell 3558. Our study is based on a sample of 12 galaxies. We observed the clusters with the GMRT at 235, 325 and 610 MHz, and with the VLA at 8.46 GHz. We complemented our study with the TGSS at 150 MHz, the SUMSS at 843 MHz and ATCA at 1380, 1400, 2380, and 4790 MHz data. Optical imaging with ESO-VST and mid-IR coverage with WISE are also available for the host galaxies. We found deep differences in the properties of the radio emission of the BCGs in the two cluster complexes. The BCGs in the A3528 complex and in A3556, which are relaxed cool-core objects, are powerful active radio galaxies. They also present hints of restarted activity. On the contrary, the BCGs in A3558 and A3562, which are well known merging systems, are very faint, or quiet, in the radio band. The optical and IR properties of the galaxies are fairly similar in the two complexes, showing all passive red galaxies. Our study shows remarkable differences in the radio properties of the BGCs, which we relate to the different dynamical state of the host cluster. On the contrary, the lack of changes between such different environments in the optical band suggests that the dynamical state of galaxy clusters does not affect the optical counterparts of the radio galaxies, at least over the life-time of the radio emission. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.06904v1-abstract-full').style.display = 'none'; document.getElementById('1807.06904v1-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> 18 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 11 figures, 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 620, A25 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1806.04692">arXiv:1806.04692</a> <span> [<a href="https://arxiv.org/pdf/1806.04692">pdf</a>, <a href="https://arxiv.org/ps/1806.04692">ps</a>, <a href="https://arxiv.org/format/1806.04692">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/stz229">10.1093/mnras/stz229 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> AGN Feedback in Galaxy Group 3C 88: Cavities, Shock and Jet Reorientation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Liu%2C+W">Wenhao Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Sun%2C+M">Ming Sun</a>, <a href="/search/astro-ph?searchtype=author&query=Nulsen%2C+P">Paul Nulsen</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+T">Tracy Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Sarazin%2C+C">Craig Sarazin</a>, <a href="/search/astro-ph?searchtype=author&query=Forman%2C+W">William Forman</a>, <a href="/search/astro-ph?searchtype=author&query=Gaspari%2C+M">Massimo Gaspari</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Lal%2C+D+V">Dharam Vir Lal</a>, <a href="/search/astro-ph?searchtype=author&query=Edge%2C+T">Tim Edge</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="1806.04692v2-abstract-short" style="display: inline;"> We present results from the deep Chandra observation (105 ksec), together with new Giant Metrewave Radio Telescope and Very Large Array data of the AGN outburst in the radio-loud galaxy group 3C 88. The system shows a prominent X-ray cavity on the eastern side with a diameter of $\sim$50 kpc at $\sim28$ kpc from the nucleus. The total enthalpy of the cavity is $3.8\times10^{58}$ erg and the averag… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.04692v2-abstract-full').style.display = 'inline'; document.getElementById('1806.04692v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1806.04692v2-abstract-full" style="display: none;"> We present results from the deep Chandra observation (105 ksec), together with new Giant Metrewave Radio Telescope and Very Large Array data of the AGN outburst in the radio-loud galaxy group 3C 88. The system shows a prominent X-ray cavity on the eastern side with a diameter of $\sim$50 kpc at $\sim28$ kpc from the nucleus. The total enthalpy of the cavity is $3.8\times10^{58}$ erg and the average power required to inflate the X-ray bubble is $\sim2.0\times10^{43}$ erg s^-1. From surface brightness profiles we detect a shock with a Mach number of $M=1.4\pm0.2$, consistent with the value obtained from temperature jump. The shock energy is estimated to be $1.9\times10^{59}$ erg. The size and total enthalpy of the cavity in 3C 88 are the largest known in galaxy groups, as well as the shock energy. The eastern X-ray cavity is not aligned with the radio jet axis. This factor, combined with the radio morphology, strongly suggests jet reorientation in the last tens of million years. The bright rim and arm features surrounding the cavity show metallicity enhancement, suggesting they originated as high metallicity gas from the group center, lifted by the rising X-ray bubbles. Our Chandra study of 3C 88 also reveals that galaxy groups with powerful radio AGN can have high cavity power, although deep X-ray observations are typically required to confirm the cavities in galaxy groups. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.04692v2-abstract-full').style.display = 'none'; document.getElementById('1806.04692v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 February, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 15 figures, MNRAS accepted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1805.01900">arXiv:1805.01900</a> <span> [<a href="https://arxiv.org/pdf/1805.01900">pdf</a>, <a href="https://arxiv.org/format/1805.01900">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </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/sty1125">10.1093/mnras/sty1125 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First evidence of diffuse ultra-steep-spectrum radio emission surrounding the cool core of a cluster </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Savini%2C+F">Federica Savini</a>, <a href="/search/astro-ph?searchtype=author&query=Bonafede%2C+A">Annalisa Bonafede</a>, <a href="/search/astro-ph?searchtype=author&query=Brueggen%2C+M">Marcus Brueggen</a>, <a href="/search/astro-ph?searchtype=author&query=van+Weeren%2C+R">Reinout van Weeren</a>, <a href="/search/astro-ph?searchtype=author&query=Brunetti%2C+G">Gianfranco Brunetti</a>, <a href="/search/astro-ph?searchtype=author&query=Intema%2C+H">Huib Intema</a>, <a href="/search/astro-ph?searchtype=author&query=Botteon%2C+A">Andrea Botteon</a>, <a href="/search/astro-ph?searchtype=author&query=Shimwell%2C+T">Timothy Shimwell</a>, <a href="/search/astro-ph?searchtype=author&query=Wilber%2C+A">Amanda Wilber</a>, <a href="/search/astro-ph?searchtype=author&query=Rafferty%2C+D">David Rafferty</a>, <a href="/search/astro-ph?searchtype=author&query=Giacintucci%2C+S">Simona Giacintucci</a>, <a href="/search/astro-ph?searchtype=author&query=Cassano%2C+R">Rossella Cassano</a>, <a href="/search/astro-ph?searchtype=author&query=Cuciti%2C+V">Virginia Cuciti</a>, <a href="/search/astro-ph?searchtype=author&query=de+Gasperin%2C+F">Francesco de Gasperin</a>, <a href="/search/astro-ph?searchtype=author&query=Roettgering%2C+H">Huub Roettgering</a>, <a href="/search/astro-ph?searchtype=author&query=Hoeft%2C+M">Matthias Hoeft</a>, <a href="/search/astro-ph?searchtype=author&query=White%2C+G">Glenn White</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="1805.01900v1-abstract-short" style="display: inline;"> Diffuse synchrotron radio emission from cosmic-ray electrons is observed at the center of a number of galaxy clusters. These sources can be classified either as giant radio halos, which occur in merging clusters, or as mini halos, which are found only in cool-core clusters. In this paper, we present the first discovery of a cool-core cluster with an associated mini halo that also shows ultra-steep… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.01900v1-abstract-full').style.display = 'inline'; document.getElementById('1805.01900v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1805.01900v1-abstract-full" style="display: none;"> Diffuse synchrotron radio emission from cosmic-ray electrons is observed at the center of a number of galaxy clusters. These sources can be classified either as giant radio halos, which occur in merging clusters, or as mini halos, which are found only in cool-core clusters. In this paper, we present the first discovery of a cool-core cluster with an associated mini halo that also shows ultra-steep-spectrum emission extending well beyond the core that resembles radio halo emission. The large-scale component is discovered thanks to LOFAR observations at 144 MHz. We also analyse GMRT observations at 610 MHz to characterise the spectrum of the radio emission. An X-ray analysis reveals that the cluster is slightly disturbed, and we suggest that the steep-spectrum radio emission outside the core could be produced by a minor merger that powers electron re-acceleration without disrupting the cool core. This discovery suggests that, under particular circumstances, both a mini and giant halo could co-exist in a single cluster, opening new perspectives for particle acceleration mechanisms in galaxy clusters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.01900v1-abstract-full').style.display = 'none'; document.getElementById('1805.01900v1-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 May, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2018. </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Giacintucci%2C+S&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a 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