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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <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/2502.10501">arXiv:2502.10501</a> <span> [<a href="https://arxiv.org/pdf/2502.10501">pdf</a>, <a href="https://arxiv.org/format/2502.10501">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"> An X-ray view of the Cataclysmic Variable V902 Mon: Discovery of an X-ray eclipse </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</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="2502.10501v1-abstract-short" style="display: inline;"> V902 Mon is one of a few eclipsing Intermediate Polars (IPs), and show deep eclipses in the optical lightcurves. The presence of a strong Fe K$伪$ fluorescence line in its X-ray spectrum and its low X-ray flux compared to other IPs suggests significant absorption, most likely from an accretion disk. In an observation carried out using the Nuclear Spectroscopic Telescope Array (NuSTAR), we confirm t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.10501v1-abstract-full').style.display = 'inline'; document.getElementById('2502.10501v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.10501v1-abstract-full" style="display: none;"> V902 Mon is one of a few eclipsing Intermediate Polars (IPs), and show deep eclipses in the optical lightcurves. The presence of a strong Fe K$伪$ fluorescence line in its X-ray spectrum and its low X-ray flux compared to other IPs suggests significant absorption, most likely from an accretion disk. In an observation carried out using the Nuclear Spectroscopic Telescope Array (NuSTAR), we confirm the presence of an X-ray eclipse in the energy resolved lightcurves, coincident with the optical AAVSO/CV-band lightcurves. Broadband X-ray spectral analysis using NuSTAR and XMM-Newton observations confirm a strong absorption N$_{H}$ $\sim 10^{23}$ cm$^{-2}$ local to the source, along with a high equivalent width of about 0.7 keV for a Fe K$伪$ fluorescence line. We interpret this using a model similar to an Accretion Disk Corona source, which have a very high inclination and the compact object is heavily obscured by the body of the accretion disk. We propose that the primary X-rays from the accretion column in V902 Mon is hidden from our direct view at all times by the accretion disk. In this scenario, the observed scattered X-rays indicate substantial absorption of direct X-rays by the accretion disk. Additionally, a strong Fe fluorescence line suggests reprocessing of the radiation by a more extended region, such as the pre-shock region, which could be located a few white dwarf radii above the orbital plane. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.10501v1-abstract-full').style.display = 'none'; document.getElementById('2502.10501v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 4 figures, 1 table. 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/2411.02655">arXiv:2411.02655</a> <span> [<a href="https://arxiv.org/pdf/2411.02655">pdf</a>, <a href="https://arxiv.org/format/2411.02655">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202348708">10.1051/0004-6361/202348708 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multiwavelength study of 1eRASS J085039.9-421151 with eROSITA NuSTAR and X-shooter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zainab%2C+A">Aafia Zainab</a>, <a href="/search/astro-ph?searchtype=author&query=Avakyan%2C+A">Artur Avakyan</a>, <a href="/search/astro-ph?searchtype=author&query=Doroshenko%2C+V">Victor Doroshenko</a>, <a href="/search/astro-ph?searchtype=author&query=Thalhammer%2C+P">Philipp Thalhammer</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolova-Lapa%2C+E">Ekaterina Sokolova-Lapa</a>, <a href="/search/astro-ph?searchtype=author&query=Ballhausen%2C+R">Ralf Ballhausen</a>, <a href="/search/astro-ph?searchtype=author&query=Zalot%2C+N">Nicolas Zalot</a>, <a href="/search/astro-ph?searchtype=author&query=Stierhof%2C+J">Jakob Stierhof</a>, <a href="/search/astro-ph?searchtype=author&query=Haemmerich%2C+S">Steven Haemmerich</a>, <a href="/search/astro-ph?searchtype=author&query=Diez%2C+C+M">Camille M. Diez</a>, <a href="/search/astro-ph?searchtype=author&query=Weber%2C+P">Philipp Weber</a>, <a href="/search/astro-ph?searchtype=author&query=Dauser%2C+T">Thomas Dauser</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">Katrin Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Kretschmar%2C+P">Peter Kretschmar</a>, <a href="/search/astro-ph?searchtype=author&query=Pottschmidt%2C+K">Katja Pottschmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Pradhan%2C+P">Pragati Pradhan</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Maitra%2C+C">Chandreyee Maitra</a>, <a href="/search/astro-ph?searchtype=author&query=Coley%2C+J+B">Joel B. Coley</a>, <a href="/search/astro-ph?searchtype=author&query=Blay%2C+P">Pere Blay</a>, <a href="/search/astro-ph?searchtype=author&query=Corbet%2C+R+H+D">Robin H. D. Corbet</a>, <a href="/search/astro-ph?searchtype=author&query=Rothschild%2C+R+E">Richard E. Rothschild</a>, <a href="/search/astro-ph?searchtype=author&query=Wood%2C+K">Kent Wood</a>, <a href="/search/astro-ph?searchtype=author&query=Santangelo%2C+A">Andrea Santangelo</a>, <a href="/search/astro-ph?searchtype=author&query=Heber%2C+U">Ulrich Heber</a> , et al. (1 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.02655v1-abstract-short" style="display: inline;"> The eROSITA instrument on board Spectrum-Roentgen-Gamma has completed four scans of the X-ray sky, leading to the detection of almost one million X-ray sources in eRASS1 only, including multiple new X-ray binary candidates. We report on analysis of the X-ray binary 1eRASS J085039.9-421151, using a ~55\,ks long NuSTAR observation, following its detection in each eROSITA scan. Analysis of the eROSIT… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.02655v1-abstract-full').style.display = 'inline'; document.getElementById('2411.02655v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.02655v1-abstract-full" style="display: none;"> The eROSITA instrument on board Spectrum-Roentgen-Gamma has completed four scans of the X-ray sky, leading to the detection of almost one million X-ray sources in eRASS1 only, including multiple new X-ray binary candidates. We report on analysis of the X-ray binary 1eRASS J085039.9-421151, using a ~55\,ks long NuSTAR observation, following its detection in each eROSITA scan. Analysis of the eROSITA and NuSTAR X-ray spectra in combination with X-shooter data of the optical counterpart provide evidence of an X-ray binary with a red supergiant (RSG) companion, confirming previous results, although we determine a cooler spectral type of M2-3, owing to the presence of TiO bands in the optical and near infrared spectra. The X-ray spectrum is well-described by an absorbed power law with a high energy cutoff typically applied for accreting high mass X-ray binaries. In addition, we detect a strong fluorescent neutral iron line with an equivalent width of ~700\,eV and an absorption edge, the latter indicating strong absorption by a partial covering component. It is unclear if the partial absorber is ionised. There is no significant evidence of a cyclotron resonant scattering feature. We do not detect any pulsations in the NuSTAR lightcurves, possibly on account of a large spin period that goes undetected due to insufficient statistics at low frequencies or potentially large absorption that causes pulsations to be smeared out. Even so, the low persistent luminosity, the spectral parameters observed (photon index, $螕<1.0$), and the minuscule likelihood of detection of RSG-black hole systems, suggest that the compact object is a neutron star. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.02655v1-abstract-full').style.display = 'none'; document.getElementById('2411.02655v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 11 figures, accepted by 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 693, A260 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.03500">arXiv:2410.03500</a> <span> [<a href="https://arxiv.org/pdf/2410.03500">pdf</a>, <a href="https://arxiv.org/ps/2410.03500">ps</a>, <a href="https://arxiv.org/format/2410.03500">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"> Sharp Periodic Flares and Long-Term Variability in the High-Mass X-ray Binary XTE J1829-098 from RXTE PCA, Swift BAT and MAXI Observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Corbet%2C+R+H+D">Robin H. D. Corbet</a>, <a href="/search/astro-ph?searchtype=author&query=Ballhausen%2C+R">Ralf Ballhausen</a>, <a href="/search/astro-ph?searchtype=author&query=Becker%2C+P+A">Peter A. Becker</a>, <a href="/search/astro-ph?searchtype=author&query=Coley%2C+J+B">Joel B. Coley</a>, <a href="/search/astro-ph?searchtype=author&query=Fuerst%2C+F">Felix Fuerst</a>, <a href="/search/astro-ph?searchtype=author&query=Gendreau%2C+K+C">Keith C. Gendreau</a>, <a href="/search/astro-ph?searchtype=author&query=Guillot%2C+S">Sebastien Guillot</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Jaisawal%2C+G+K">Gaurava Kumar Jaisawal</a>, <a href="/search/astro-ph?searchtype=author&query=Jenke%2C+P">Peter Jenke</a>, <a href="/search/astro-ph?searchtype=author&query=Kretschmar%2C+P">Peter Kretschmar</a>, <a href="/search/astro-ph?searchtype=author&query=Lange%2C+A">Alexander Lange</a>, <a href="/search/astro-ph?searchtype=author&query=Malacaria%2C+C">Christian Malacaria</a>, <a href="/search/astro-ph?searchtype=author&query=Ng%2C+M">Mason Ng</a>, <a href="/search/astro-ph?searchtype=author&query=Pottschmidt%2C+K">Katja Pottschmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Pradhan%2C+P">Pragati Pradhan</a>, <a href="/search/astro-ph?searchtype=author&query=Ray%2C+P+S">Paul S. Ray</a>, <a href="/search/astro-ph?searchtype=author&query=Rothschild%2C+R+E">Richard E. Rothschild</a>, <a href="/search/astro-ph?searchtype=author&query=Thalhammer%2C+P">Philipp Thalhammer</a>, <a href="/search/astro-ph?searchtype=author&query=Townsend%2C+L+J">Lee J. Townsend</a>, <a href="/search/astro-ph?searchtype=author&query=Wilms%2C+J">Joern Wilms</a>, <a href="/search/astro-ph?searchtype=author&query=Wilson-Hodge%2C+C+A">Colleen A. Wilson-Hodge</a>, <a href="/search/astro-ph?searchtype=author&query=Wolff%2C+M+T">Michael T. Wolff</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="2410.03500v1-abstract-short" style="display: inline;"> XTE J1829-098 is a transient X-ray pulsar with a period of ~7.8 s. It is a candidate Be star system, although the evidence for this is not yet definitive. We investigated the twenty-year long X-ray light curve using the Rossi X-ray Timing Explorer Proportional Counter Array (PCA), Neil Gehrels Swift Observatory Burst Alert Telescope (BAT), and the Monitor of All-sky X-ray Image (MAXI). We find tha… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.03500v1-abstract-full').style.display = 'inline'; document.getElementById('2410.03500v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.03500v1-abstract-full" style="display: none;"> XTE J1829-098 is a transient X-ray pulsar with a period of ~7.8 s. It is a candidate Be star system, although the evidence for this is not yet definitive. We investigated the twenty-year long X-ray light curve using the Rossi X-ray Timing Explorer Proportional Counter Array (PCA), Neil Gehrels Swift Observatory Burst Alert Telescope (BAT), and the Monitor of All-sky X-ray Image (MAXI). We find that all three light curves are clearly modulated on the ~244 day orbital period previously reported from PCA monitoring observations, with outbursts confined to a narrow phase range. The light curves also show that XTE J1829-098 was in an inactive state between approximately December 2008 and April 2018 and no strong outbursts occurred. Such behavior is typical of Be X-ray binary systems, with the absence of outbursts likely related to the dissipation of the Be star's decretion disk. The mean outburst shapes can be approximated with a triangular profile and, from a joint fit of this to all three light curves, we refine the orbital period to 243.95 +/- 0.04 days. The mean outburst profile does not show any asymmetry and has a total phase duration of 0.140 +/- 0.007. However, the PCA light curve shows that there is considerable cycle-to-cycle variability of the individual outbursts. We compare the properties of XTE J1829-098 with other sources that show short phase-duration outbursts, in particular GS 1843-02 (2S 1845-024) which has a very similar orbital period, but longer pulse period, and whose orbit is known to be highly eccentric. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.03500v1-abstract-full').style.display = 'none'; document.getElementById('2410.03500v1-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in the Astrophysical Journal. 21 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.11682">arXiv:2403.11682</a> <span> [<a href="https://arxiv.org/pdf/2403.11682">pdf</a>, <a href="https://arxiv.org/format/2403.11682">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202348841">10.1051/0004-6361/202348841 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An in-depth analysis of the variable cyclotron lines in GX 301$-$2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zalot%2C+N">Nicolas Zalot</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolova-Lapa%2C+E">Ekaterina Sokolova-Lapa</a>, <a href="/search/astro-ph?searchtype=author&query=Stierhof%2C+J">Jakob Stierhof</a>, <a href="/search/astro-ph?searchtype=author&query=Ballhausen%2C+R">Ralf Ballhausen</a>, <a href="/search/astro-ph?searchtype=author&query=Zainab%2C+A">Aafia Zainab</a>, <a href="/search/astro-ph?searchtype=author&query=Pottschmidt%2C+K">Katja Pottschmidt</a>, <a href="/search/astro-ph?searchtype=author&query=F%C3%BCrst%2C+F">Felix F眉rst</a>, <a href="/search/astro-ph?searchtype=author&query=Thalhammer%2C+P">Philipp Thalhammer</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Diez%2C+C+M">Camille M. Diez</a>, <a href="/search/astro-ph?searchtype=author&query=Kretschmar%2C+P">Peter Kretschmar</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+K">Katrin Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Rothschild%2C+R">Richard Rothschild</a>, <a href="/search/astro-ph?searchtype=author&query=Malacaria%2C+C">Christian Malacaria</a>, <a href="/search/astro-ph?searchtype=author&query=Pradhan%2C+P">Pragati Pradhan</a>, <a href="/search/astro-ph?searchtype=author&query=Wilms%2C+J">J枚rn Wilms</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.11682v2-abstract-short" style="display: inline;"> Context. The High-Mass X-ray Binary (HMXB) system GX 301$-$2 is a persistent source with a well-known variable cyclotron line centered at 35 keV. Recently, a second cyclotron line at 50 keV has been reported with a presumably different behavior than the 35 keV line. Aims. We investigate the presence of the newly discovered cyclotron line in the phase-averaged and phase-resolved spectra at higher… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.11682v2-abstract-full').style.display = 'inline'; document.getElementById('2403.11682v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.11682v2-abstract-full" style="display: none;"> Context. The High-Mass X-ray Binary (HMXB) system GX 301$-$2 is a persistent source with a well-known variable cyclotron line centered at 35 keV. Recently, a second cyclotron line at 50 keV has been reported with a presumably different behavior than the 35 keV line. Aims. We investigate the presence of the newly discovered cyclotron line in the phase-averaged and phase-resolved spectra at higher luminosities than before. We further aim to determine the pulse-phase variability of both lines. Methods. We analyze a NuSTAR observation of GX 301$-$2 covering the pre-periastron flare, where the source luminosity reached its peak of ${\sim} 4 \times 10^{37}\,\mathrm{erg}\,\mathrm{s}^{-1}$ in the 5-50 keV range. We analyze the phase-averaged spectra in the NuSTAR energy range from 3.5-79 keV for both the complete observation and three time segments of it. We further analyze the phase-resolved spectra and the pulse-phase variability of continuum and cyclotron line parameters. Results. We confirm that the description of the phase-averaged spectrum requires a second absorption feature at $51.5^{+1.1}_{-1.0}$ keV besides the established line at 35 keV. The statistical significance of this feature in the phase-averaged spectrum is $>99.999\%$. We further find that the 50 keV cyclotron line is present in three of eight phase bins. Conclusions. Based on the results of our analysis, we confirm that the detected absorption feature is very likely to be a cyclotron line. We discuss a variety of physical scenarios which could explain the proposed anharmonicity, but also outline circumstances under which the lines are harmonically related. We further present the cyclotron line history of GX 301$-$2 and evaluate concordance among each other. We also discuss an alternative spectral model including cyclotron line emission wings. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.11682v2-abstract-full').style.display = 'none'; document.getElementById('2403.11682v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">accepted for publication in Astronomy & Astrophysics, 20 pages, 16 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 686, A95 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.09172">arXiv:2312.09172</a> <span> [<a href="https://arxiv.org/pdf/2312.09172">pdf</a>, <a href="https://arxiv.org/ps/2312.09172">ps</a>, <a href="https://arxiv.org/format/2312.09172">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"> Swift/XRT observations of superorbital modulations in wind-fed supergiant X-ray binaries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Romano%2C+P">P. Romano</a>, <a href="/search/astro-ph?searchtype=author&query=Bozzo%2C+E">E. Bozzo</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">N. Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Corbet%2C+R+H+D">R. H. D. Corbet</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="2312.09172v1-abstract-short" style="display: inline;"> We present the first Swift/XRT long-term monitoring of 2S 0114+650, a wind-fed supergiant X-ray binary for which both orbital and superorbital periods are known (P_orb~11.6d and P_sup~0.8d). Our campaign, summing up to ~ 79ks, is the most intense and complete sampling of the X-ray light curve of this source with a sensitive pointed X-ray instrument, and covers 17 orbital, and 6 superorbital cycles… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.09172v1-abstract-full').style.display = 'inline'; document.getElementById('2312.09172v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.09172v1-abstract-full" style="display: none;"> We present the first Swift/XRT long-term monitoring of 2S 0114+650, a wind-fed supergiant X-ray binary for which both orbital and superorbital periods are known (P_orb~11.6d and P_sup~0.8d). Our campaign, summing up to ~ 79ks, is the most intense and complete sampling of the X-ray light curve of this source with a sensitive pointed X-ray instrument, and covers 17 orbital, and 6 superorbital cycles. The combination of flexibility, sensitivity, and soft X-ray coverage of XRT allowed us to confirm previously reported spectral changes along the orbital cycle of the source and unveil the variability in its spectral parameters as a function of the superorbital phase. For completeness, we also report on a similar analysis carried out by exploiting XRT archival data on three additional wind-fed supergiant X-ray binaries IGR J16418-4532, IGR J16479-4514, and IGR J16493-4348. For these sources, the archival data provided coverage along several superorbital cycles but our analysis could not reveal any significant spectral variability. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.09172v1-abstract-full').style.display = 'none'; document.getElementById('2312.09172v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 December, 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 Monthly Notices of the Royal Astronomical Society. 17 pages, 7 tables, 5 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/2311.17156">arXiv:2311.17156</a> <span> [<a href="https://arxiv.org/pdf/2311.17156">pdf</a>, <a href="https://arxiv.org/format/2311.17156">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> X-rays from RS Ophiuchi's 2021 eruption: shocks in and out of ionization equilibrium </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">Jennifer L. Sokoloski</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="2311.17156v1-abstract-short" style="display: inline;"> The recurrent nova RS Ophiuchi (RS Oph) underwent its most recent eruption on 8 August 2021 and became the first nova to produce both detectable GeV and TeV emission. We used extensive X-ray monitoring with the Neutron Star Interior Composition Explorer Mission (NICER) to model the X-ray spectrum and probe the shock conditions throughout the 2021 eruption. The rapidly evolving NICER spectra consis… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.17156v1-abstract-full').style.display = 'inline'; document.getElementById('2311.17156v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.17156v1-abstract-full" style="display: none;"> The recurrent nova RS Ophiuchi (RS Oph) underwent its most recent eruption on 8 August 2021 and became the first nova to produce both detectable GeV and TeV emission. We used extensive X-ray monitoring with the Neutron Star Interior Composition Explorer Mission (NICER) to model the X-ray spectrum and probe the shock conditions throughout the 2021 eruption. The rapidly evolving NICER spectra consisted of both line and continuum emission that could not be accounted for using a single-temperature collisional equilibrium plasma model with an absorber that fully covered the source. We successfully modelled the NICER spectrum as a non-equilibrium ionization collisional plasma with partial-covering absorption. The temperature of the the non-equilibrium plasma show a peak on Day 5 with a kT of approximately 24 keV. The increase in temperature during the first five days could have been due to increasing contribution to the X-ray emission from material behind fast polar shocks or a decrease is the amount of energy being drained from shocks into particle acceleration during that time period. The absorption showed a change from fully covering the source to having a covering fraction of roughly 0.4, suggesting a geometrical evolution of the shock region within the complex global distribution of the circumstellar material. These findings show the evidence of the ejecta interacting with some dense equatorial shell initially and with less dense material in the bipolar regions at later times during the eruption. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.17156v1-abstract-full').style.display = 'none'; document.getElementById('2311.17156v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 November, 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">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/2310.17563">arXiv:2310.17563</a> <span> [<a href="https://arxiv.org/pdf/2310.17563">pdf</a>, <a href="https://arxiv.org/format/2310.17563">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> Breakthroughs in Cool Star Physics with the Line Emission Mapper X-ray Probe </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Drake%2C+J+J">Jeremy J. Drake</a>, <a href="/search/astro-ph?searchtype=author&query=Gomez%2C+J+A">Juli谩n Alvarado Gomez</a>, <a href="/search/astro-ph?searchtype=author&query=Argiroffi%2C+C">Costanza Argiroffi</a>, <a href="/search/astro-ph?searchtype=author&query=Flaccomio%2C+E">Ettore Flaccomio</a>, <a href="/search/astro-ph?searchtype=author&query=Garraffo%2C+C">Cecilia Garraffo</a>, <a href="/search/astro-ph?searchtype=author&query=Grosso%2C+N">Nicolas Grosso</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Karovska%2C+M">Margarita Karovska</a>, <a href="/search/astro-ph?searchtype=author&query=Kashyap%2C+V+L">Vinay L. Kashyap</a>, <a href="/search/astro-ph?searchtype=author&query=Monsch%2C+K">Kristina Monsch</a>, <a href="/search/astro-ph?searchtype=author&query=Ness%2C+J">Jan-Uwe Ness</a>, <a href="/search/astro-ph?searchtype=author&query=Sciortino%2C+S">Salvatore Sciortino</a>, <a href="/search/astro-ph?searchtype=author&query=Wargelin%2C+B">Bradford Wargelin</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="2310.17563v1-abstract-short" style="display: inline;"> We outline some of the highlights of the scientific case for the advancement of stellar high energy physics using the Line Emission Mapper X-ray Probe ({\it LEM}). The key to advancements with LEM lie in its large effective area -- up to 100 times that of the {\it Chandra} MEG -- and 1~eV spectral resolution. The large effective area opens up for the first time the ability to study time-dependent… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.17563v1-abstract-full').style.display = 'inline'; document.getElementById('2310.17563v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.17563v1-abstract-full" style="display: none;"> We outline some of the highlights of the scientific case for the advancement of stellar high energy physics using the Line Emission Mapper X-ray Probe ({\it LEM}). The key to advancements with LEM lie in its large effective area -- up to 100 times that of the {\it Chandra} MEG -- and 1~eV spectral resolution. The large effective area opens up for the first time the ability to study time-dependent phenomena on their natural timescales at high resolution, such as flares and coronal mass ejections, and also opens the sky to much fainter targets than available to {\it Chandra} or {\it XMM-Newton}. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.17563v1-abstract-full').style.display = 'none'; document.getElementById('2310.17563v1-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">A Line Emission Mapper X-ray Probe White Paper</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.07318">arXiv:2302.07318</a> <span> [<a href="https://arxiv.org/pdf/2302.07318">pdf</a>, <a href="https://arxiv.org/format/2302.07318">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/acbc19">10.3847/1538-4357/acbc19 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigating the superorbital modulations in 4U 1909+07, IGR J16418-4532 and IGR J16479-4514 with Swift XRT, BAT and NuSTAR observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Corbet%2C+R+H+D">Robin H. D. Corbet</a>, <a href="/search/astro-ph?searchtype=author&query=Coley%2C+J+B">Joel B. Coley</a>, <a href="/search/astro-ph?searchtype=author&query=Pottschmidt%2C+K">Katja Pottschmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Fuerst%2C+F">Felix Fuerst</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="2302.07318v1-abstract-short" style="display: inline;"> A puzzling variety of superorbital modulations have been discovered in several supergiant High-Mass X-ray binaries (sgHMXBs). To investigate the mechanisms driving these superorbital modulations, we have analyzed long-term Neil Gehrels Swift Observatory (Swift) Burst Alert Telescope (BAT) observations of three sgHMXBs: 4U 1909+07, IGR J16418-4532 and IGR J16479-4514 and constructed their dynamic p… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.07318v1-abstract-full').style.display = 'inline'; document.getElementById('2302.07318v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.07318v1-abstract-full" style="display: none;"> A puzzling variety of superorbital modulations have been discovered in several supergiant High-Mass X-ray binaries (sgHMXBs). To investigate the mechanisms driving these superorbital modulations, we have analyzed long-term Neil Gehrels Swift Observatory (Swift) Burst Alert Telescope (BAT) observations of three sgHMXBs: 4U 1909+07, IGR J16418-4532 and IGR J16479-4514 and constructed their dynamic power spectra and superorbital intensity profiles. These Swift BAT observations are complemented by pointed Swift X-ray Telescope (XRT) and Nuclear Spectroscopic Telescope Array (NuSTAR) observations performed near the predicted maximum and minimum phase of a single superorbital cycle for each of these sources. The BAT dynamic power spectra show changes in the strength of the superorbital modulation on timescales of years, with either the peak at the fundamental frequency and/or the second harmonic present at different times for all three sources. The pointed Swift XRT and NuSTAR observations show no significant differences between the pulse profiles and spectral parameters at the superorbital maximum and minimum phase. This is likely due to the fact the superorbital modulation had weakened significantly during the times when the NuSTAR observations were carried out for all three sources. The results from the Swift XRT, BAT and NuSTAR analysis indicate the possible presence of multiple co-rotating interaction regions (CIRs) in the stellar winds of the supergiant stars, although a structured stellar wind from the supergiant star due to tidal oscillations cannot be ruled out. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.07318v1-abstract-full').style.display = 'none'; document.getElementById('2302.07318v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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 the Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.00346">arXiv:2204.00346</a> <span> [<a href="https://arxiv.org/pdf/2204.00346">pdf</a>, <a href="https://arxiv.org/format/2204.00346">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac6184">10.3847/1538-4357/ac6184 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Comparative Study of Machine Learning Methods for X-ray Binary Classification </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=de+Beurs%2C+Z+L">Zoe L. de Beurs</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">N. Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Gopalan%2C+G">G. Gopalan</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+S+D">S. D. Vrtilek</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="2204.00346v4-abstract-short" style="display: inline;"> X-ray Binaries (XRBs) consist of a compact object that accretes material from an orbiting secondary star. The most secure method we have for determining if the compact object is a black hole is to determine its mass: this is limited to bright objects, and requires substantial time-intensive spectroscopic monitoring. With new X-ray sources being discovered with different X-ray observatories, develo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.00346v4-abstract-full').style.display = 'inline'; document.getElementById('2204.00346v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.00346v4-abstract-full" style="display: none;"> X-ray Binaries (XRBs) consist of a compact object that accretes material from an orbiting secondary star. The most secure method we have for determining if the compact object is a black hole is to determine its mass: this is limited to bright objects, and requires substantial time-intensive spectroscopic monitoring. With new X-ray sources being discovered with different X-ray observatories, developing efficient, robust means to classify compact objects becomes increasingly important. We compare three machine learning classification methods (Bayesian Gaussian Processes (BGP), K-Nearest Neighbors (KNN), Support Vector Machines (SVM)) for determining the compact objects as neutron stars or black holes (BHs) in XRB systems. Each machine learning method uses spatial patterns which exist between systems of the same type in 3D Color-Color-Intensity diagrams. We used lightcurves extracted using six years of data with MAXI/GSC for 44 representative sources. We find that all three methods are highly accurate in distinguishing pulsing from non-pulsing neutron stars (NPNS) with 95\% of NPNS and 100\% of pulsars accurately predicted. All three methods have high accuracy distinguishing BHs from pulsars (92\%) but continue to confuse BHs with a subclass of NPNS, called the Bursters, with KNN doing the best at only 50\% accuracy for predicting BHs. The precision of all three methods is high, providing equivalent results over 5-10 independent runs. In a future work, we suggest a fourth dimension be incorporated to mitigate the confusion of BHs with Bursters. This work paves the way towards more robust methods to efficiently distinguish BHs, NPNS, and pulsars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.00346v4-abstract-full').style.display = 'none'; document.getElementById('2204.00346v4-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 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 17 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/2203.05652">arXiv:2203.05652</a> <span> [<a href="https://arxiv.org/pdf/2203.05652">pdf</a>, <a href="https://arxiv.org/ps/2203.05652">ps</a>, <a href="https://arxiv.org/format/2203.05652">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/ac6fe2">10.3847/1538-4357/ac6fe2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gamma-ray Eclipses and Orbital Modulation Transitions in the Candidate Redback 4FGL J1702.7-5655 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Corbet%2C+R+H+D">R. H. D. Corbet</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">L. Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Coley%2C+J+B">J. B. Coley</a>, <a href="/search/astro-ph?searchtype=author&query=Dubus%2C+G">G. Dubus</a>, <a href="/search/astro-ph?searchtype=author&query=Edwards%2C+P+G">P. G. Edwards</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">N. Islam</a>, <a href="/search/astro-ph?searchtype=author&query=McBride%2C+V+A">V. A. McBride</a>, <a href="/search/astro-ph?searchtype=author&query=Stevens%2C+J">J. Stevens</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">J. Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Swihart%2C+S+J">S. J. Swihart</a>, <a href="/search/astro-ph?searchtype=author&query=Townsend%2C+L+J">L. J. Townsend</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="2203.05652v2-abstract-short" style="display: inline;"> Observations with the Fermi Large Area Telescope (LAT) of the gamma-ray source 4FGL J1702.7-5655, previously classified as a candidate millisecond pulsar, show highly-significant modulation at a period of 0.2438033 days (~ 5.85 hours). Further examination of the folded light curve indicates the presence of narrow eclipses, suggesting this is a redback binary system. An examination of the long-term… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.05652v2-abstract-full').style.display = 'inline'; document.getElementById('2203.05652v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.05652v2-abstract-full" style="display: none;"> Observations with the Fermi Large Area Telescope (LAT) of the gamma-ray source 4FGL J1702.7-5655, previously classified as a candidate millisecond pulsar, show highly-significant modulation at a period of 0.2438033 days (~ 5.85 hours). Further examination of the folded light curve indicates the presence of narrow eclipses, suggesting this is a redback binary system. An examination of the long-term properties of the modulation over 13 years of LAT observations indicates that the orbital modulation of the gamma-rays changed from a simple eclipse before early 2013, to a broader, more easily detected, quasi-sinusoidal modulation. In addition, the time of the eclipse shifts to ~0.05 later in phase. This change in the orbital modulation properties is, however, not accompanied by a significant overall change in gamma-ray flux or spectrum. The quasi-sinusoidal component peaks ~0.5 out of phase with the eclipse, which would indicate inferior conjunction of the compact object in the system. Swift X-ray Telescope observations reveal a possible X-ray counterpart within the LAT error ellipse. However, radio observations obtained with the Australia Telescope Compact Array do not detect a source in the region. 4FGL J1702.7-5655 appears to have changed its state in 2013, perhaps related to changes in the intrabinary shock in the system. We discuss how the properties of 4FGL J1702.7-5655 compare to other binary millisecond pulsars that have exhibited orbital modulation in gamma rays. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.05652v2-abstract-full').style.display = 'none'; document.getElementById('2203.05652v2-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 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in the Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.11376">arXiv:2201.11376</a> <span> [<a href="https://arxiv.org/pdf/2201.11376">pdf</a>, <a href="https://arxiv.org/format/2201.11376">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/ac524f">10.3847/1538-4357/ac524f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Accreting on the edge: a luminosity-dependent cyclotron line in the Be/X-ray Binary 2S 1553-542 accompanied by accretion regimes transition </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Malacaria%2C+C">Christian Malacaria</a>, <a href="/search/astro-ph?searchtype=author&query=Bhargava%2C+Y">Yash Bhargava</a>, <a href="/search/astro-ph?searchtype=author&query=Coley%2C+J+B">Joel B. Coley</a>, <a href="/search/astro-ph?searchtype=author&query=Ducci%2C+L">Lorenzo Ducci</a>, <a href="/search/astro-ph?searchtype=author&query=Pradhan%2C+P">Pragati Pradhan</a>, <a href="/search/astro-ph?searchtype=author&query=Ballhausen%2C+R">Ralf Ballhausen</a>, <a href="/search/astro-ph?searchtype=author&query=Fuerst%2C+F">Felix Fuerst</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Jaisawal%2C+G+K">Gaurava K. Jaisawal</a>, <a href="/search/astro-ph?searchtype=author&query=Jenke%2C+P">Peter Jenke</a>, <a href="/search/astro-ph?searchtype=author&query=Kretschmar%2C+P">Peter Kretschmar</a>, <a href="/search/astro-ph?searchtype=author&query=Kreykenbohm%2C+I">Ingo Kreykenbohm</a>, <a href="/search/astro-ph?searchtype=author&query=Pottschmidt%2C+K">Katja Pottschmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolova-Lapa%2C+E">Ekaterina Sokolova-Lapa</a>, <a href="/search/astro-ph?searchtype=author&query=Staubert%2C+R">Rudiger Staubert</a>, <a href="/search/astro-ph?searchtype=author&query=Wilms%2C+J">Joern Wilms</a>, <a href="/search/astro-ph?searchtype=author&query=Wilson-Hodge%2C+C+A">Colleen A. Wilson-Hodge</a>, <a href="/search/astro-ph?searchtype=author&query=Wolff%2C+M+T">Michael T. Wolff</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="2201.11376v2-abstract-short" style="display: inline;"> Accreting X-ray pulsars (XRPs) undergo luminous X-ray outbursts during which the luminosity-dependent spectral and timing features of the neutron star's emission can be analyzed in detail, thus shedding light on the accretion regime at work. We took advantage of a monitoring campaign performed with NuSTAR, Swift/XRT, AstroSat and NICER, to follow the Be/X-ray Binary 2S 1553-542 along one of its ra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.11376v2-abstract-full').style.display = 'inline'; document.getElementById('2201.11376v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.11376v2-abstract-full" style="display: none;"> Accreting X-ray pulsars (XRPs) undergo luminous X-ray outbursts during which the luminosity-dependent spectral and timing features of the neutron star's emission can be analyzed in detail, thus shedding light on the accretion regime at work. We took advantage of a monitoring campaign performed with NuSTAR, Swift/XRT, AstroSat and NICER, to follow the Be/X-ray Binary 2S 1553-542 along one of its rare outbursts and trace its spectral and timing evolution. We report the discovery of a luminosity-dependent cyclotron line energy for the first time in this source. The pulse profiles and pulsed fraction also show variability along the outburst, consistently with the interpretation that the source transitions from the sub-critical to the super-critical accretion regime, separated by a critical luminosity of L$_{crit}\approx4\times10^{37}$ erg/s. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.11376v2-abstract-full').style.display = 'none'; document.getElementById('2201.11376v2-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 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted on ApJ. 11 pages, 7 figures, 3 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/2107.05636">arXiv:2107.05636</a> <span> [<a href="https://arxiv.org/pdf/2107.05636">pdf</a>, <a href="https://arxiv.org/ps/2107.05636">ps</a>, <a href="https://arxiv.org/format/2107.05636">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/ac134e">10.3847/1538-4357/ac134e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The role of complex ionized absorber in the soft X-ray spectra of Intermediate Polars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.05636v1-abstract-short" style="display: inline;"> In magnetic Cataclysmic Variables (mCVs), X-ray radiation originates from the shock heated multi-temperature plasma in the post-shock region near the white dwarf surface. These X-rays are modified by a complex distribution of absorbers in the pre-shock region. The presence of photo-ionized lines and warm absorber features in the soft X-ray spectra of these mCVs suggests that these absorbers are io… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.05636v1-abstract-full').style.display = 'inline'; document.getElementById('2107.05636v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.05636v1-abstract-full" style="display: none;"> In magnetic Cataclysmic Variables (mCVs), X-ray radiation originates from the shock heated multi-temperature plasma in the post-shock region near the white dwarf surface. These X-rays are modified by a complex distribution of absorbers in the pre-shock region. The presence of photo-ionized lines and warm absorber features in the soft X-ray spectra of these mCVs suggests that these absorbers are ionized. We developed the ionized complex absorber model zxipab, which is represented by a power-law distribution of ionized absorbers in the pre-shock flow. Using the ionized absorber model zxipab along with a cooling flow model and a reflection component, we model the broadband Chandra/HETG and NuSTAR spectra of two IPs: NY Lup and V1223 Sgr. We find that this model describes well many of the H and He like emission lines from medium Z elements, which arises from the collisionally excited plasma. However the model fails to account for some of the He like triplets from medium Z elements, which points towards its photo-ionization origin. We do not find a compelling evidence for a blackbody component to model the soft excess seen in the residuals of the Chandra/HETG spectra, which could be due to the uncertainties in estimation of the interstellar absorption of these sources using Chandra/HETG data and/or excess fluxes seen in some photo-ionized emission lines which are not accounted by the cooling flow model. We describe the implications of this model with respect to the geometry of the pre-shock region in these two IPs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.05636v1-abstract-full').style.display = 'none'; document.getElementById('2107.05636v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 7 figures, 4 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/2106.14937">arXiv:2106.14937</a> <span> [<a href="https://arxiv.org/pdf/2106.14937">pdf</a>, <a href="https://arxiv.org/format/2106.14937">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/10.3847/1538-4365/ac0f79">10.3847/1538-4365/ac0f79 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An XMM-Newton Early-type Galaxy Atlas </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D">Dong-Woo Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Lin%2C+K">Kenneth Lin</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=Anderson%2C+C">Craig Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Fabbiano%2C+G">Giuseppina Fabbiano</a>, <a href="/search/astro-ph?searchtype=author&query=Lauer%2C+J">Jennifer Lauer</a>, <a href="/search/astro-ph?searchtype=author&query=Morgan%2C+D">Douglas Morgan</a>, <a href="/search/astro-ph?searchtype=author&query=Mossman%2C+A">Amy Mossman</a>, <a href="/search/astro-ph?searchtype=author&query=Paggi%2C+A">Alessandro Paggi</a>, <a href="/search/astro-ph?searchtype=author&query=Trinchieri%2C+G">Ginevra Trinchieri</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+S">Saeqa Vrtilek</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="2106.14937v1-abstract-short" style="display: inline;"> The distribution of hot interstellar medium in early-type galaxies bears the imprint of the various astrophysical processes it underwent during its evolution. The X-ray observations of these galaxies have identified various structural features related to AGN and stellar feedback and environmental effects such as merging and sloshing. In our XMM-Newton Galaxy Atlas (NGA) project, we analyze archiva… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.14937v1-abstract-full').style.display = 'inline'; document.getElementById('2106.14937v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.14937v1-abstract-full" style="display: none;"> The distribution of hot interstellar medium in early-type galaxies bears the imprint of the various astrophysical processes it underwent during its evolution. The X-ray observations of these galaxies have identified various structural features related to AGN and stellar feedback and environmental effects such as merging and sloshing. In our XMM-Newton Galaxy Atlas (NGA) project, we analyze archival observations of 38 ETGs, utilizing the high sensitivity and large field of view of XMM-Newton to construct spatially resolved 2D spectral maps of the hot gas halos. To illustrate our NGA data products in conjunction with the Chandra Galaxy Atlas (Kim et al. 2019), we describe two distinct galaxies - NGC 4636 and NGC 1550, in detail. We discuss their evolutionary history with a particular focus on the asymmetric distribution of metal-enriched, low-entropy gas caused by sloshing and AGN- driven uplift. We will release the NGA data products to a dedicated website, which users can download to perform further analyses. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.14937v1-abstract-full').style.display = 'none'; document.getElementById('2106.14937v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 6 figures, 2 tables. Accepted for publication in ApJS. The data-products along with the quick look results are here: https://cxc.cfa.harvard.edu/GalaxyAtlas/NGA/v1/</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.05810">arXiv:2007.05810</a> <span> [<a href="https://arxiv.org/pdf/2007.05810">pdf</a>, <a href="https://arxiv.org/format/2007.05810">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.newast.2020.101514">10.1016/j.newast.2020.101514 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Comparing X-ray color selection in separating X-ray binary classes using Color-Color-Intensity diagrams </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Vrtilek%2C+S+D">S. D. Vrtilek</a>, <a href="/search/astro-ph?searchtype=author&query=Boroson%2C+B">Bram Boroson</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+D+-">D. -W. Kim</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=McCollough%2C+M+L">M. L. McCollough</a>, <a href="/search/astro-ph?searchtype=author&query=Fabbiano%2C+G">G. Fabbiano</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+C">C. Anderson</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=D%27Abrusco%2C+R">R. D'Abrusco</a>, <a href="/search/astro-ph?searchtype=author&query=Fruscione%2C+A">A. Fruscione</a>, <a href="/search/astro-ph?searchtype=author&query=Lauer%2C+J+L">J. L. Lauer</a>, <a href="/search/astro-ph?searchtype=author&query=Morgan%2C+D">D. Morgan</a>, <a href="/search/astro-ph?searchtype=author&query=Mossman%2C+A">A. Mossman</a>, <a href="/search/astro-ph?searchtype=author&query=Paggi%2C+A">A. Paggi</a>, <a href="/search/astro-ph?searchtype=author&query=Trinchieri%2C+G">G. Trinchieri</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="2007.05810v2-abstract-short" style="display: inline;"> X-ray binaries exhibit a wide range of properties but there are few accepted methods to determine the nature of the compact object. Color-Color-Intensity diagrams have been suggested as a means of distinguishing between systems containing black holes from those containing neutron stars. However, this technique has been verified with data from only one instrument (RXTE/ASM) with a single set of X-r… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.05810v2-abstract-full').style.display = 'inline'; document.getElementById('2007.05810v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.05810v2-abstract-full" style="display: none;"> X-ray binaries exhibit a wide range of properties but there are few accepted methods to determine the nature of the compact object. Color-Color-Intensity diagrams have been suggested as a means of distinguishing between systems containing black holes from those containing neutron stars. However, this technique has been verified with data from only one instrument (RXTE/ASM) with a single set of X-ray colors defined using data available only in pre-determined energy bands. We test a selection of X-ray colors with a more sensitive instrument to determine the reliability of this method. We use data from the MAXI Gas Slit Camera, which allows users to specify energy-bands. We test X-ray colors that have been previously defined in the literature as well as ones that we define specifically in this paper. A representative set of systems are used to construct Color-Color-Intensity diagrams in each set of colors to determine which are best for separating different classes. For studying individual sources certain bands are more effective than others. For a specified energy range, the separation of soft states in black hole binaries was possible only where both soft and hard colors included information from the lowest energy band. We confirm that Color-Color-Intensity diagrams can distinguish between systems containing black holes or neutron stars in all X-ray colors tested; this suggests an universality in the accretion processes governing these different classes. We suggest possible physical processes driving different classes of X-ray binaries to different locations in Color-Color-Intensity diagrams. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.05810v2-abstract-full').style.display = 'none'; document.getElementById('2007.05810v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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, 19 figures. Accepted in New 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/1911.01066">arXiv:1911.01066</a> <span> [<a href="https://arxiv.org/pdf/1911.01066">pdf</a>, <a href="https://arxiv.org/ps/1911.01066">ps</a>, <a href="https://arxiv.org/format/1911.01066">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/stz3082">10.1093/mnras/stz3082 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigating a unique partial eclipse in the High Mass X-ray Binary IGR J16393-4643 with Swift-XRT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kabiraj%2C+S">Sanhita Kabiraj</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</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="1911.01066v1-abstract-short" style="display: inline;"> The orbital profile of the High Mass X-ray binary IGR J16393-4643 shows a dip in its X-ray intensity, which was previously interpreted as an eclipse. Unlike most eclipsing HMXBs, where the X-ray eclipses are about two orders of magnitude fainter compared to the out of eclipse emission, this particular eclipse like feature is narrow and partial, casting doubt if it is indeed an eclipse. To further… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.01066v1-abstract-full').style.display = 'inline'; document.getElementById('1911.01066v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.01066v1-abstract-full" style="display: none;"> The orbital profile of the High Mass X-ray binary IGR J16393-4643 shows a dip in its X-ray intensity, which was previously interpreted as an eclipse. Unlike most eclipsing HMXBs, where the X-ray eclipses are about two orders of magnitude fainter compared to the out of eclipse emission, this particular eclipse like feature is narrow and partial, casting doubt if it is indeed an eclipse. To further investigate the nature of this low intensity orbital phase, we use a large number of observations with Swift-XRT, covering the entire orbital phase. The soft X-ray observations also show this low intensity phase, which is about 30% of the intensity during rest of the orbit. We also carried out orbital phase resolved spectroscopy to compare the change in the spectral parameters inside and outside of this low intensity state. The results indicate that this low intensity state might not be an eclipse, as previously thought but absorption in the stellar corona. We have also provided the inclination angle of the binary for grazing eclipse caused by the stellar corona. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.01066v1-abstract-full').style.display = 'none'; document.getElementById('1911.01066v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 November, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2019. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.10386">arXiv:1905.10386</a> <span> [<a href="https://arxiv.org/pdf/1905.10386">pdf</a>, <a href="https://arxiv.org/ps/1905.10386">ps</a>, <a href="https://arxiv.org/format/1905.10386">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/10.1093/mnras/stz1446">10.1093/mnras/stz1446 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Cosmological implications of the composite spectra of galactic X-ray binaries constructed using MAXI data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Ghara%2C+R">Raghunath Ghara</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</a>, <a href="/search/astro-ph?searchtype=author&query=Choudhury%2C+T+R">T. Roy Choudhury</a>, <a href="/search/astro-ph?searchtype=author&query=Nath%2C+B+B">Biman B. Nath</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="1905.10386v1-abstract-short" style="display: inline;"> We have investigated the long term average spectral properties of galactic X-ray binaries in the energy range of 3-20 keV, using long term monitoring data from MAXI -Gas Slit Camera (GSC). These long term average spectra are used to construct separately the composite spectra of galactic High Mass X-ray binaries (HMXBs) and Low Mass X-ray binaries (LMXBs). These composite spectra can be described e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.10386v1-abstract-full').style.display = 'inline'; document.getElementById('1905.10386v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.10386v1-abstract-full" style="display: none;"> We have investigated the long term average spectral properties of galactic X-ray binaries in the energy range of 3-20 keV, using long term monitoring data from MAXI -Gas Slit Camera (GSC). These long term average spectra are used to construct separately the composite spectra of galactic High Mass X-ray binaries (HMXBs) and Low Mass X-ray binaries (LMXBs). These composite spectra can be described empirically with piece-wise power-law with three components. X-rays from HMXBs are considered as important contributors to heating and ionization of neutral hydrogen in the intergalactic medium during the Epoch of Reionization. Using the above empirical form of the composite HMXB spectra extrapolated to lower energies as an input, we have studied the impact of these sources on the 21-cm signal using the outputs of N-body simulation and 1D radiative transfer. The heating due to the composite spectrum is less patchy compared to power-law spectrum with a spectral index $伪= 1.5$, used in previous studies. The amplitude of the heating peak of large scale power spectrum, when plotted as a function of the redshift, is less for the composite spectrum. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.10386v1-abstract-full').style.display = 'none'; document.getElementById('1905.10386v1-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 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">13 pages, 6 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/1807.06984">arXiv:1807.06984</a> <span> [<a href="https://arxiv.org/pdf/1807.06984">pdf</a>, <a href="https://arxiv.org/ps/1807.06984">ps</a>, <a href="https://arxiv.org/format/1807.06984">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/sty2597">10.1093/mnras/sty2597 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Correlations between radio and bolometric fluxes in GX 339-4 and H1743-322 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Zdziarski%2C+A+A">Andrzej A. Zdziarski</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="1807.06984v2-abstract-short" style="display: inline;"> Compact radio jets are ubiquitous in stellar-mass black-hole binaries in their hard spectral state. Empirical relations between the radio and narrow-band X-ray fluxes have been used to understand the connection between their accretion discs and jets. However, a narrow-band (e.g., 1--10 or 3--9 keV) X-ray flux can be a poor proxy for either the bolometric luminosity or the mass accretion rate. Here… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.06984v2-abstract-full').style.display = 'inline'; document.getElementById('1807.06984v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.06984v2-abstract-full" style="display: none;"> Compact radio jets are ubiquitous in stellar-mass black-hole binaries in their hard spectral state. Empirical relations between the radio and narrow-band X-ray fluxes have been used to understand the connection between their accretion discs and jets. However, a narrow-band (e.g., 1--10 or 3--9 keV) X-ray flux can be a poor proxy for either the bolometric luminosity or the mass accretion rate. Here, we study correlations between the radio and unabsorbed broad-band X-ray fluxes, the latter providing good estimates of the bolometric flux. We consider GX 339--4, the benchmark object for the main branch of the correlation, and H1743--322, the first source found to be an outlier of the correlation. The obtained power-law dependencies of the radio flux on the bolometric flux have significantly different indices from those found for the narrow X-ray bands. Also, the radio/bolometric flux correlations for the rise of the outbursts are found to be significantly different from those for the outburst decline. This points to a possible existence of a jet hysteresis in the radio/X-ray source evolution, in addition to that seen in the hardness/flux diagram of low-mass X-ray binaries. The correlation during the rise of the outbursts is similar for both GX 339--4 and H1743--322. The correlation for the decline of the outbursts for H1743--322 lies below that of GX 339--4 at intermediate X-ray fluxes, whereas it approaches the standard correlation at lower X-ray luminosities. We also compare these correlations to those for the high-mass X-ray binaries Cyg X-1 and Cyg X-3. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.06984v2-abstract-full').style.display = 'none'; document.getElementById('1807.06984v2-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 September, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 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">MNRAS, in press, 9 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.06638">arXiv:1705.06638</a> <span> [<a href="https://arxiv.org/pdf/1705.06638">pdf</a>, <a href="https://arxiv.org/format/1705.06638">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/stx2283">10.1093/mnras/stx2283 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Analysis of NuSTAR and Suzaku observations of Cyg X-1 in the hard state: evidence for a truncated disc geometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Basak%2C+R">Rupal Basak</a>, <a href="/search/astro-ph?searchtype=author&query=Zdziarski%2C+A+A">Andrzej A. Zdziarski</a>, <a href="/search/astro-ph?searchtype=author&query=Parker%2C+M">Michael Parker</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</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="1705.06638v2-abstract-short" style="display: inline;"> The geometry of the accretion flow in black-hole X-ray binaries in the hard state, in particular the position of the disc inner edge, has been a subject of intense debate in recent years. We address this issue by performing a spectral study of simultaneous observations of Cyg X-1 in the hard state by NuSTAR and Suzaku. The same data were analysed before, and modelled by a lamppost containing hybri… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.06638v2-abstract-full').style.display = 'inline'; document.getElementById('1705.06638v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.06638v2-abstract-full" style="display: none;"> The geometry of the accretion flow in black-hole X-ray binaries in the hard state, in particular the position of the disc inner edge, has been a subject of intense debate in recent years. We address this issue by performing a spectral study of simultaneous observations of Cyg X-1 in the hard state by NuSTAR and Suzaku. The same data were analysed before, and modelled by a lamppost containing hybrid electrons and located very close to the horizon, which emission was incident on a surrounding disc extending almost to the innermost stable circular orbit. We re-analyse the incident continuum model and show that it suffers from the lack of physical self-consistency. Still, the good fit to the data provided by this model indicates that the real continuum has a similar shape. We find it features a strong soft X-ray excess below a few keV, which we model as a soft thermal-Comptonization component, in addition to the main hard thermal-Compton component. This continuum model with reflection of both components yields the overall lowest $蠂^2$ and has a geometry with a hot inner accretion flow and a disc truncated at $\simeq$13--20 gravitational radii. On the other hand, we have also found spectral solution with a lamppost at a large height and a disc that can extend to the innnermost stable circular orbit, though somewhat statistically worse. Overall, we find the fitted truncation radius depends on the assumed continuum and geometry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.06638v2-abstract-full').style.display = 'none'; document.getElementById('1705.06638v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 September, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">MNRAS, in press</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.06297">arXiv:1608.06297</a> <span> [<a href="https://arxiv.org/pdf/1608.06297">pdf</a>, <a href="https://arxiv.org/ps/1608.06297">ps</a>, <a href="https://arxiv.org/format/1608.06297">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/stw2037">10.1093/mnras/stw2037 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Variability study of the High Mass X-ray Binary IGR J18027--2016 with {\it Swift}--XRT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aftab%2C+N">Nafisa Aftab</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</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="1608.06297v1-abstract-short" style="display: inline;"> We report the results from pulsations and spectral analysis of a large number of observations of the HMXB pulsar IGR J18027--2016 with {\it Swift}--XRT, carried out at different orbital phases. In some orbital phases, as seen in different XRT observations, the X-ray intensity is found to vary by a large factor, of about $\sim$50. In all the observations with sufficient number of source X-ray photo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.06297v1-abstract-full').style.display = 'inline'; document.getElementById('1608.06297v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.06297v1-abstract-full" style="display: none;"> We report the results from pulsations and spectral analysis of a large number of observations of the HMXB pulsar IGR J18027--2016 with {\it Swift}--XRT, carried out at different orbital phases. In some orbital phases, as seen in different XRT observations, the X-ray intensity is found to vary by a large factor, of about $\sim$50. In all the observations with sufficient number of source X-ray photons, pulsations have been detected around the previously known pulse period of $\sim$140 sec, When detected, the pulse profiles do not show any significant variation over a flux difference of a factor of $\sim$3. The absorption column density is found to be large before and after the eclipse. We discuss various possible reasons for intensity and spectral variations in IGR J18027--2016, such as clumpy wind and hydrodynamic instabilities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.06297v1-abstract-full').style.display = 'none'; document.getElementById('1608.06297v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in MNRAS, Comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1606.01059">arXiv:1606.01059</a> <span> [<a href="https://arxiv.org/pdf/1606.01059">pdf</a>, <a href="https://arxiv.org/ps/1606.01059">ps</a>, <a href="https://arxiv.org/format/1606.01059">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/stw1299">10.1093/mnras/stw1299 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Orbital evolution and search for eccentricity and apsidal motion in the eclipsing HMXB 4U 1700-37 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</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="1606.01059v2-abstract-short" style="display: inline;"> In the absence of detectable pulsations in the eclipsing High Mass X-ray binary 4U 1700-37, the orbital period decay is necessarily determined from the eclipse timing measurements. We have used the earlier reported mid-eclipse time measurements of 4U 1700-37 together with the new measurements from long term light curves obtained with the all sky monitors RXTE-ASM, Swift-BAT and MAXI-GSC, as well a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.01059v2-abstract-full').style.display = 'inline'; document.getElementById('1606.01059v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1606.01059v2-abstract-full" style="display: none;"> In the absence of detectable pulsations in the eclipsing High Mass X-ray binary 4U 1700-37, the orbital period decay is necessarily determined from the eclipse timing measurements. We have used the earlier reported mid-eclipse time measurements of 4U 1700-37 together with the new measurements from long term light curves obtained with the all sky monitors RXTE-ASM, Swift-BAT and MAXI-GSC, as well as observations with RXTE-PCA, to measure the long term orbital evolution of the binary. The orbital period decay rate of the system is estimated to be ${\dot{P}}/P = -(4.7 \pm 1.9) \times 10^{-7}$ yr$^{-1}$, smaller compared to its previous estimates. We have also used the mid-eclipse times and the eclipse duration measurements obtained from 10 years long X-ray light-curve with Swift-BAT to separately put constraints on the eccentricity of the binary system and attempted to measure any apsidal motion. For an apsidal motion rate greater than 5 degrees per year, the eccentricity is found to be less than 0.008, which limits our ability to determine the apsidal motion rate from the current data. We discuss the discrepancy of the current limit of eccentricity with the earlier reported values from radial velocity measurements of the companion star. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.01059v2-abstract-full').style.display = 'none'; document.getElementById('1606.01059v2-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, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">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/1602.08287">arXiv:1602.08287</a> <span> [<a href="https://arxiv.org/pdf/1602.08287">pdf</a>, <a href="https://arxiv.org/ps/1602.08287">ps</a>, <a href="https://arxiv.org/format/1602.08287">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.newast.2016.02.008">10.1016/j.newast.2016.02.008 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Effects of variability of X-ray binaries on the X-ray luminosity functions of Milky Way </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</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="1602.08287v1-abstract-short" style="display: inline;"> The X-ray luminosity functions of galaxies have become a useful tool for population studies of X-ray binaries in them. The availability of long term light-curves of X-ray binaries with the All Sky X-ray Monitors opens up the possibility of constructing X-ray luminosity functions, by also including the intensity variation effects of the galactic X-ray binaries. We have constructed multiple realizat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08287v1-abstract-full').style.display = 'inline'; document.getElementById('1602.08287v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.08287v1-abstract-full" style="display: none;"> The X-ray luminosity functions of galaxies have become a useful tool for population studies of X-ray binaries in them. The availability of long term light-curves of X-ray binaries with the All Sky X-ray Monitors opens up the possibility of constructing X-ray luminosity functions, by also including the intensity variation effects of the galactic X-ray binaries. We have constructed multiple realizations of the X-ray luminosity functions (XLFs) of Milky Way, using the long term light-curves of sources obtained in the 2-10 keV energy band with the RXTE-ASM. The observed spread seen in the value of slope of both HMXB and LMXB XLFs are due to inclusion of variable luminosities of X-ray binaries in construction of these XLFs as well as finite sample effects. XLFs constructed for galactic HMXBs in the luminosity range 10^{36} - 10^{39} erg/sec is described by a power-law model with a mean power-law index of -0.48 and a spread due to variability of HMXBs as 0.19. XLFs constructed for galactic LMXBs in the luminosity range 10^{36} - 10^{39} erg/sec has a shape of cut-off power-law with mean power-law index of -0.31 and a spread due to variability of LMXBs as 0.07. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08287v1-abstract-full').style.display = 'none'; document.getElementById('1602.08287v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in New Astronomy</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> New Astronomy, 2016, Volume 47, page 81-87 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1411.3108">arXiv:1411.3108</a> <span> [<a href="https://arxiv.org/pdf/1411.3108">pdf</a>, <a href="https://arxiv.org/ps/1411.3108">ps</a>, <a href="https://arxiv.org/format/1411.3108">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/stu2395">10.1093/mnras/stu2395 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Suzaku view of IGR J16393-4643 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Maitra%2C+C">Chandreyee Maitra</a>, <a href="/search/astro-ph?searchtype=author&query=Pradhan%2C+P">Pragati Pradhan</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</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="1411.3108v1-abstract-short" style="display: inline;"> The pulsar IGR J16393-4643 belongs to a class of highly absorbed supergiant HMXBs, characterised by very high column density of absorbing matter. We present the results of the simultaneous broad-band pulsation and spectrum analysis, from a 44 kilosec Suzaku observation of the source. The orbital intensity profile created with the SWIFT-BAT light-curve shows an indication of IGR J16393-4643 being a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.3108v1-abstract-full').style.display = 'inline'; document.getElementById('1411.3108v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1411.3108v1-abstract-full" style="display: none;"> The pulsar IGR J16393-4643 belongs to a class of highly absorbed supergiant HMXBs, characterised by very high column density of absorbing matter. We present the results of the simultaneous broad-band pulsation and spectrum analysis, from a 44 kilosec Suzaku observation of the source. The orbital intensity profile created with the SWIFT-BAT light-curve shows an indication of IGR J16393-4643 being an eclipsing system with a short eclipse semi-angle $胃_{E} \sim$ 17$^{\circ}$. For a supergiant companion star with a 20 R$_{\odot}$ radius, this implies an inclination of the orbital plane in the range of 39$^{\circ}$-57$^{\circ}$, whereas for a main sequence B star as the companion with a 10 R$_{\odot}$ radius, the inclination of the orbital plane is in the range of 60$^{\circ}$-77$^{\circ}$. Pulse profiles created for different energy bands, have complex morphology which shows some energy dependence and increases in pulse fraction with energy. We have also investigated broad-band spectral characteristics, for phase averaged and resolving the pulse phase into peak phase and trough phase. The phase averaged spectrum has a very high N$_{H} (\sim 3 \times 10^{23}$ cm$^{-2}$) and is described by power-law ($螕\sim$ 0.9) with a high energy cut-off above 20 keV. We find a change in the spectral index in the peak phase and trough phase, implying an underlying change in the source spectrum. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.3108v1-abstract-full').style.display = 'none'; document.getElementById('1411.3108v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 November, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 7 figures. Accepted for publication in MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Monthly Notices of the Royal Astronomical Society, 2015, Volume 446, Issue 4, p.4148-4154 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1407.5252">arXiv:1407.5252</a> <span> [<a href="https://arxiv.org/pdf/1407.5252">pdf</a>, <a href="https://arxiv.org/ps/1407.5252">ps</a>, <a href="https://arxiv.org/format/1407.5252">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/stu1034">10.1093/mnras/stu1034 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Variations in the pulsation and spectral characteristics of OAO 1657-415 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pradhan%2C+P">Pragati Pradhan</a>, <a href="/search/astro-ph?searchtype=author&query=Maitra%2C+C">Chandreyee Maitra</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B+C">B. C. Paul</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="1407.5252v1-abstract-short" style="display: inline;"> We present broad-band pulsation and spectral characteristics of the accreting X-ray pulsar OAO 1657--415 with a 2.2 d long \emph{Suzaku} observation carried out covering its orbital phase range $\sim$ 0.12--0.34, with respect to the mid-eclipse. During the last third of the observation, the X-ray count rate in both the X-ray Imaging Spectrometer (XIS) and the HXD-PIN instruments increased by a fac… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.5252v1-abstract-full').style.display = 'inline'; document.getElementById('1407.5252v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1407.5252v1-abstract-full" style="display: none;"> We present broad-band pulsation and spectral characteristics of the accreting X-ray pulsar OAO 1657--415 with a 2.2 d long \emph{Suzaku} observation carried out covering its orbital phase range $\sim$ 0.12--0.34, with respect to the mid-eclipse. During the last third of the observation, the X-ray count rate in both the X-ray Imaging Spectrometer (XIS) and the HXD-PIN instruments increased by a factor of more than 10. During this observation, the hardness ratio also changed by a factor of more than 5, uncorrelated with the intensity variations. In two segments of the observation, lasting for $\sim$ 30--50 ks, the hardness ratio is very high. In these segments, the spectrum shows a large absorption column density and correspondingly large equivalent widths of the iron fluorescence lines. We found no conclusive evidence for the presence of a cyclotron line in the broad-band X-ray spectrum with \emph{Suzaku}. The pulse profile, especially in the XIS energy band shows evolution with time but not so with energy. We discuss the nature of the intensity variations, and variations of the absorption column density and emission lines during the duration of the observation as would be expected due to a clumpy stellar wind of the supergiant companion star. These results indicate that OAO 1657--415 has characteristics intermediate to the normal supergiant systems and the systems that show fast X-ray transient phenomena. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.5252v1-abstract-full').style.display = 'none'; document.getElementById('1407.5252v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 July, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 10 figures, published in MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Monthly Notices of the Royal Astronomical Society 2014 442 (2): 2691-2700 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1404.3902">arXiv:1404.3902</a> <span> [<a href="https://arxiv.org/pdf/1404.3902">pdf</a>, <a href="https://arxiv.org/ps/1404.3902">ps</a>, <a href="https://arxiv.org/format/1404.3902">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/stu756">10.1093/mnras/stu756 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Orbital phase resolved spectroscopy of GX 301-2 with MAXI </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</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="1404.3902v1-abstract-short" style="display: inline;"> GX 301-2, a bright HMXB with an orbital period of 41.5 days, exhibits stable periodic orbital intensity modulations with a strong pre-periastron X-ray flare. Several models have been proposed to explain the accretion at different orbital phases, invoking accretion via stellar wind, equatorial disk, and accretion stream from the companion star. We present results from exhaustive orbital phase resol… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.3902v1-abstract-full').style.display = 'inline'; document.getElementById('1404.3902v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1404.3902v1-abstract-full" style="display: none;"> GX 301-2, a bright HMXB with an orbital period of 41.5 days, exhibits stable periodic orbital intensity modulations with a strong pre-periastron X-ray flare. Several models have been proposed to explain the accretion at different orbital phases, invoking accretion via stellar wind, equatorial disk, and accretion stream from the companion star. We present results from exhaustive orbital phase resolved spectroscopic measurements of GX 301-2 using data from the Gas Slit Camera onboard MAXI. Using spectroscopic analysis of the MAXI data with unprecendented orbital coverage for many orbits continuously, we have found a strong orbital dependence of the absorption column density and equivalent width of the iron emission line. A very large equivalent width of the iron line along with a small value of the column density in the orbital phase range 0.10-0.30 after the periastron passage indicates presence of high density absorbing matter behind the neutron star in these orbital phase range. A low energy excess is also found in the spectrum at orbital phases around the pre-periastron X-ray flare. The orbital dependence of these parameters are then used to examine the various models about mode of accretion onto the neutron star in GX 301-2. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.3902v1-abstract-full').style.display = 'none'; document.getElementById('1404.3902v1-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 April, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 6 figures. Accepted for publication in MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Monthly Notices of the Royal Astronomical Society, 2014, Volume 441, Issue 3, p.2539-2545 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1309.4581">arXiv:1309.4581</a> <span> [<a href="https://arxiv.org/pdf/1309.4581">pdf</a>, <a href="https://arxiv.org/ps/1309.4581">ps</a>, <a href="https://arxiv.org/format/1309.4581">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"> Average spectral properties of galactic X-ray binaries with 3 years of MAXI data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nazma Islam</a>, <a href="/search/astro-ph?searchtype=author&query=Mihara%2C+T">Tatehiro Mihara</a>, <a href="/search/astro-ph?searchtype=author&query=Sugizaki%2C+M">Mutsumi Sugizaki</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</a>, <a href="/search/astro-ph?searchtype=author&query=Nath%2C+B+B">Biman B. Nath</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="1309.4581v1-abstract-short" style="display: inline;"> The energy spectra of X-ray binaries (XRBs) have been investigated during the last few decades with many observatories in different energy bands and with different energy resolutions. However, these studies are carried out in selected states of XRBs like during outbursts, transitions, quiescent states, and are always done in limited time windows of pointed observations. It is now possible to inves… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1309.4581v1-abstract-full').style.display = 'inline'; document.getElementById('1309.4581v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1309.4581v1-abstract-full" style="display: none;"> The energy spectra of X-ray binaries (XRBs) have been investigated during the last few decades with many observatories in different energy bands and with different energy resolutions. However, these studies are carried out in selected states of XRBs like during outbursts, transitions, quiescent states, and are always done in limited time windows of pointed observations. It is now possible to investigate the long term averaged spectra of a large number of X-ray binaries with the all sky monitor MAXI, which also has a broad energy band. Here we present the average spectral behaviour of a few representative XRBs. The long term averaged spectrum of Cyg X-1 is described by a sum of two power-laws having $螕_{1}$ ~ 2.8 and $螕_{2}$ ~ 1.2, along with a multi color disk blackbody having an inner disk temperature of 0.5 keV, GX 301-2 is described by a power-law with a high energy cut-off at $E_{c}$ ~ 15 keV and a blackbody component at 0.2 keV and that of Aql X-1 is described by a multi color disk blackbody at 2 keV and a power-law of $螕$ ~ 2.2. We have also constructed the combined X-ray spectrum of the X-ray binaries in the Milky Way, which can be compared to the XRBs spectra of other galaxies observed with Chandra and XMM-Newton. These measurements are also relevant to investigate the X-ray interaction with the ISM and its contribution to the ionising X-ray background in the early universe. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1309.4581v1-abstract-full').style.display = 'none'; document.getElementById('1309.4581v1-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 September, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To be published in ASI Conference Series on "Recent Trends in the Study of Compact Objects: Theory and Observation"</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1307.1237">arXiv:1307.1237</a> <span> [<a href="https://arxiv.org/pdf/1307.1237">pdf</a>, <a href="https://arxiv.org/ps/1307.1237">ps</a>, <a href="https://arxiv.org/format/1307.1237">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</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/10.1140/epjc/s10052-014-2750-5">10.1140/epjc/s10052-014-2750-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Possible existence of wormholes in the galactic halo region </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Rahaman%2C+F">Farook Rahaman</a>, <a href="/search/astro-ph?searchtype=author&query=Kuhfittig%2C+P+K+F">P. K. F. Kuhfittig</a>, <a href="/search/astro-ph?searchtype=author&query=Ray%2C+S">Saibal Ray</a>, <a href="/search/astro-ph?searchtype=author&query=Islam%2C+N">Nasarul Islam</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="1307.1237v4-abstract-short" style="display: inline;"> Two observational results, the density profile from simulations performed in the $螞$CDM scenario and the observed flat galactic rotation curves, are taken as input with the aim of showing that the galactic halo possesses some of the characteristics needed to support traversable wormholes. This result should be sufficient to provide an incentive for scientists to seek observational evidence for wor… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1307.1237v4-abstract-full').style.display = 'inline'; document.getElementById('1307.1237v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1307.1237v4-abstract-full" style="display: none;"> Two observational results, the density profile from simulations performed in the $螞$CDM scenario and the observed flat galactic rotation curves, are taken as input with the aim of showing that the galactic halo possesses some of the characteristics needed to support traversable wormholes. This result should be sufficient to provide an incentive for scientists to seek observational evidence for wormholes in the galactic halo region. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1307.1237v4-abstract-full').style.display = 'none'; document.getElementById('1307.1237v4-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 February, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 July, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 3 figures, 1 table, Eur. Phys. J. C (2014) 74:2750, DOI 10.1140/epjc/s10052-014-2750-5</span> </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

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