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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Mukai%2C+K&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Mukai%2C+K&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Mukai%2C+K&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Mukai%2C+K&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=Mukai%2C+K&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> <li> <a href="/search/?searchtype=author&query=Mukai%2C+K&start=200" class="pagination-link " aria-label="Page 5" aria-current="page">5 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/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/2501.16582">arXiv:2501.16582</a> <span> [<a href="https://arxiv.org/pdf/2501.16582">pdf</a>, <a href="https://arxiv.org/format/2501.16582">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> The S-PLUS 12-band photometry as a powerful tool for discovery and classification: ten cataclysmic variables in a proof-of-concept study </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=de+Oliveira%2C+R+L">Raimundo Lopes de Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=de+Araujo%2C+A+S">Amanda S. de Araujo</a>, <a href="/search/astro-ph?searchtype=author&query=Krabbe%2C+A+C">Angela C. Krabbe</a>, <a href="/search/astro-ph?searchtype=author&query=de+Oliveira%2C+C+L+M">Claudia L. Mendes de Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Gutierrez-Soto%2C+L+A">Luis A. Gutierrez-Soto</a>, <a href="/search/astro-ph?searchtype=author&query=Kanaan%2C+A">Antonio Kanaan</a>, <a href="/search/astro-ph?searchtype=author&query=Eleuterio%2C+R">Romualdo Eleuterio</a>, <a href="/search/astro-ph?searchtype=author&query=Fernandes%2C+M+B">Marcelo Borges Fernandes</a>, <a href="/search/astro-ph?searchtype=author&query=Quispe-Huaynasi%2C+F">Fredi Quispe-Huaynasi</a>, <a href="/search/astro-ph?searchtype=author&query=Schoenell%2C+W">William Schoenell</a>, <a href="/search/astro-ph?searchtype=author&query=Ribeiro%2C+T">Tiago Ribeiro</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="2501.16582v1-abstract-short" style="display: inline;"> Multi-band photometric surveys provide a straightforward way to discover and classify astrophysical objects systematically, enabling the study of a large number of targets at relatively low cost. Here we introduce an alternative approach to select Accreting White Dwarf (AWD) candidates following their spectral energy distribution, entirely supported by the twelve photometric bands of the Southern… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.16582v1-abstract-full').style.display = 'inline'; document.getElementById('2501.16582v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.16582v1-abstract-full" style="display: none;"> Multi-band photometric surveys provide a straightforward way to discover and classify astrophysical objects systematically, enabling the study of a large number of targets at relatively low cost. Here we introduce an alternative approach to select Accreting White Dwarf (AWD) candidates following their spectral energy distribution, entirely supported by the twelve photometric bands of the Southern Photometric Local Universe Survey (S-PLUS). The method was validated with optical spectroscopic follow-up with the Gemini South telescope which unambiguously established ten systems as cataclysmic variables (CVs), alongside Swift X-ray observations of four of them. Among the ten CVs presented here are those that may be low-luminosity intermediate polars or WZ Sge-type dwarf novae with rare outbursts, two subclasses that can be easily missed in time-domain and X-ray surveys, the two methods currently dominating the discovery of new CVs. Our approach based on S-PLUS provides an important, complementary tool to uncover the total population of CVs and the complete set of its subclasses, which is an important step towards a full understanding of close binary evolution, including the origin of magnetic fields in white dwarfs and the physics of accretion. Finally, we highlight the potential of S-PLUS beyond AWDs, serving other surveys in the characterization of their sources. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.16582v1-abstract-full').style.display = 'none'; document.getElementById('2501.16582v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">Accepted for publication in ApJL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.15108">arXiv:2412.15108</a> <span> [<a href="https://arxiv.org/pdf/2412.15108">pdf</a>, <a href="https://arxiv.org/format/2412.15108">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Revisiting the Classics: On the Optical Colours of Novae as Standard Crayons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Craig%2C+P">Peter Craig</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">Elias Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">Jay Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Stone%2C+A">Ashley Stone</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">Kirill V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">Adam Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Fl%C3%B3%2C+J+G">Joan Guarro Fl贸</a>, <a href="/search/astro-ph?searchtype=author&query=Boussin%2C+C">Christophe Boussin</a>, <a href="/search/astro-ph?searchtype=author&query=Charbonnel%2C+S">St茅phane Charbonnel</a>, <a href="/search/astro-ph?searchtype=author&query=Garde%2C+O">Olivier Garde</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="2412.15108v1-abstract-short" style="display: inline;"> We present a systematic study of the $BVRI$ colours of novae over the course of their eruptions. Where possible, interstellar reddening was measured using the equivalent widths of Diffuse Interstellar Bands (DIBs). Some novae lack spectra with sufficient resolution and signal-to-noise ratios; therefore, we supplement as necessary with 3D and 2D dust maps. Utilising only novae with DIB- or 3D-map-b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.15108v1-abstract-full').style.display = 'inline'; document.getElementById('2412.15108v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.15108v1-abstract-full" style="display: none;"> We present a systematic study of the $BVRI$ colours of novae over the course of their eruptions. Where possible, interstellar reddening was measured using the equivalent widths of Diffuse Interstellar Bands (DIBs). Some novae lack spectra with sufficient resolution and signal-to-noise ratios; therefore, we supplement as necessary with 3D and 2D dust maps. Utilising only novae with DIB- or 3D-map-based $E(B-V)$, we find an average intrinsic $(B-V)_0$ colour of novae at $V$-band light curve peak of 0.18 with a standard deviation of 0.31, based on a sample of 23 novae. When the light curve has declined by 2 magnitudes ($t_2$), we find an average $(B-V)_0 = -0.02$ with a standard deviation of 0.19. These average colours are consistent with previous findings, although the spreads are larger than previously found due to more accurate reddening estimates. We also examined the intrinsic $(R-I)_0$ and $(V-R)_0$ colours across our sample. These colours behave similarly to $(B-V)_0$, except that the $(V-R)_0$ colour gets redder after peak, likely due to the contributions of emission line flux. We searched for correlations between nova colours and $t_2$, peak $V$-band absolute magnitude, and GeV $纬$-ray luminosity, but find no statistically significant correlations. Nova colours can therefore be used as standard "crayons" to estimate interstellar reddening from photometry alone, with 0.2--0.3 mag uncertainty. We present a novel Bayesian strategy for estimating distances to Galactic novae based on these $E(B-V)$ measurements, independent of assumptions about luminosity, built using 3D dust maps and a stellar mass model of the Milky Way. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.15108v1-abstract-full').style.display = 'none'; document.getElementById('2412.15108v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">19 pages, 21 Figures. Submitted to MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.00855">arXiv:2412.00855</a> <span> [<a href="https://arxiv.org/pdf/2412.00855">pdf</a>, <a href="https://arxiv.org/format/2412.00855">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> A new way to find symbiotic stars: accretion disc detection with optical survey photometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lucy%2C+A+B">A. B. Lucy</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">J. L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Luna%2C+G+J+M">G. J. M. Luna</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Nu%C3%B1ez%2C+N+E">N. E. Nu帽ez</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D+A+H">D. A. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Breytenbach%2C+H">H. Breytenbach</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">B. Paul</a>, <a href="/search/astro-ph?searchtype=author&query=Potter%2C+S+B">S. B. Potter</a>, <a href="/search/astro-ph?searchtype=author&query=Manick%2C+R">R. Manick</a>, <a href="/search/astro-ph?searchtype=author&query=Howell%2C+D+A">D. A. Howell</a>, <a href="/search/astro-ph?searchtype=author&query=Wolf%2C+C">C. Wolf</a>, <a href="/search/astro-ph?searchtype=author&query=Onken%2C+C+A">C. A. Onken</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="2412.00855v1-abstract-short" style="display: inline;"> Symbiotic stars are binaries in which a cool and evolved star of luminosity class I-III accretes onto a smaller companion. However, direct accretion signatures like disc flickering and boundary layer X-rays are typically outshone or suppressed by the luminous giant, shell burning on the accreting white dwarf, and the illuminated wind nebula. We present a new way to find symbiotics that is less bia… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.00855v1-abstract-full').style.display = 'inline'; document.getElementById('2412.00855v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.00855v1-abstract-full" style="display: none;"> Symbiotic stars are binaries in which a cool and evolved star of luminosity class I-III accretes onto a smaller companion. However, direct accretion signatures like disc flickering and boundary layer X-rays are typically outshone or suppressed by the luminous giant, shell burning on the accreting white dwarf, and the illuminated wind nebula. We present a new way to find symbiotics that is less biased against directly-detectable accretion discs than methods based on narrow-band H$伪$ photometry or objective prism plate surveys. We identified outliers in SkyMapper survey photometry, using reconstructed uvg snapshot colours and rapid variability among the three exposures of each 20-minute SkyMapper Main Survey filter sequence, from a sample of 366,721 luminous red objects. We found that SkyMapper catalog colours of large-amplitude pulsating giants must be corrected for variability, and that flickering is detectable with only three data points. Our methods probed a different region of parameter space than a recent search for accreting-only symbiotics in the GALAH survey, while being surprisingly concordant with another survey's infrared detection algorithm. We discovered 12 new symbiotics, including four with optical accretion disc flickering. Two of the optical flickerers exhibited boundary-layer hard X-rays. We also identified 10 symbiotic candidates, and discovered likely optical flickering in the known symbiotic V1044 Cen (CD-36 8436). We conclude that at least 20% of the true population of symbiotics exhibit detectable optical flickering from the inner accretion disc, the majority of which do not meet the H$伪$ detection thresholds used to find symbiotics in typical narrow-band surveys. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.00855v1-abstract-full').style.display = 'none'; document.getElementById('2412.00855v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to MNRAS. 34 pages, 17 figures (from 20 image files), 5 tables. Centered on A4 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/2410.01125">arXiv:2410.01125</a> <span> [<a href="https://arxiv.org/pdf/2410.01125">pdf</a>, <a href="https://arxiv.org/format/2410.01125">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"> The Symbiotic Recurrent Nova V745 Sco at Radio Wavelengths </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Molina%2C+I">Isabella Molina</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">Justin D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">Elias Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Mioduszewski%2C+A+J">Amy J. Mioduszewski</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">Kirill V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">Jay Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Craig%2C+P">Peter Craig</a>, <a href="/search/astro-ph?searchtype=author&query=Dong%2C+D">Dillon Dong</a>, <a href="/search/astro-ph?searchtype=author&query=Harris%2C+C+E">Chelsea E. Harris</a>, <a href="/search/astro-ph?searchtype=author&query=Nyamai%2C+M+M">Miriam M. Nyamai</a>, <a href="/search/astro-ph?searchtype=author&query=Rupen%2C+M+P">Michael P. Rupen</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">Jennifer L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Walter%2C+F+M">Frederick M. Walter</a>, <a href="/search/astro-ph?searchtype=author&query=Weston%2C+J+H+S">Jennifer H. S. Weston</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+M+N">Montana N. Williams</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="2410.01125v1-abstract-short" style="display: inline;"> V745 Sco is a Galactic symbiotic recurrent nova with nova eruptions in 1937, 1989 and 2014. We study the behavior of V745 Sco at radio wavelengths (0.6-37,GHz), covering both its 1989 and 2014 eruptions and informed by optical, X-ray, and $纬$-ray data. The radio light curves are synchrotron-dominated. Surprisingly, compared to expectations for synchrotron emission from explosive transients such as… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.01125v1-abstract-full').style.display = 'inline'; document.getElementById('2410.01125v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.01125v1-abstract-full" style="display: none;"> V745 Sco is a Galactic symbiotic recurrent nova with nova eruptions in 1937, 1989 and 2014. We study the behavior of V745 Sco at radio wavelengths (0.6-37,GHz), covering both its 1989 and 2014 eruptions and informed by optical, X-ray, and $纬$-ray data. The radio light curves are synchrotron-dominated. Surprisingly, compared to expectations for synchrotron emission from explosive transients such as radio supernovae, the light curves spanning 0.6-37 GHz all peak around the same time ($\sim$18-26 days after eruption) and with similar flux densities (5-9 mJy).We model the synchrotron light curves as interaction of the nova ejecta with the red giant wind, but find that simple spherically symmetric models with wind-like circumstellar material (CSM) cannot explain the radio light curve. Instead, we conclude that the shock suddenly breaks out of a dense CSM absorbing screen around 20 days after eruption, and then expands into a relatively low density wind ($\dot{M}_{out} \approx 10^{-9}-10^{-8}$ M$_{\odot}$ yr$^{-1}$ for $v_w = 10$ km s$^{-1}$) out to $\sim$1 year post-eruption. The dense, close-in CSM may be an equatorial density enhancement or a more spherical red giant wind with $\dot{M}_{in} \approx [5-10] \times 10^{-7}$ M$_{\odot}$ yr$^{-1}$, truncated beyond several $\times 10^{14}$ cm. The outer lower-density CSM would not be visible in typical radio observations of Type Ia supernovae: V745 Sco cannot be ruled out as a Type Ia progenitor based on CSM constraints alone.Complementary constraints from the free-free radio optical depth and the synchrotron luminosity imply the shock is efficient at accelerating relativistic electrons and amplifying magnetic fields, with $蔚_e$ and $蔚_B \approx 0.01-0.1$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.01125v1-abstract-full').style.display = 'none'; document.getElementById('2410.01125v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 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">21 pages, 20 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/2409.15429">arXiv:2409.15429</a> <span> [<a href="https://arxiv.org/pdf/2409.15429">pdf</a>, <a href="https://arxiv.org/format/2409.15429">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202450498">10.1051/0004-6361/202450498 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Indications of magnetic accretion in Swift J0826.2-7033 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Rawat%2C+N">Nikita Rawat</a>, <a href="/search/astro-ph?searchtype=author&query=De+Martino%2C+D">Domitilla De Martino</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Falanga%2C+M">Maurizio Falanga</a>, <a href="/search/astro-ph?searchtype=author&query=Masetti%2C+N">Nicola Masetti</a>, <a href="/search/astro-ph?searchtype=author&query=Pandey%2C+J+C">Jeewan C. Pandey</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.15429v1-abstract-short" style="display: inline;"> We present our findings from the first long X-ray observation of the hard X-ray source Swift J0826.2-7033 with XMM-Newton, which has shown characteristics of magnetic accretion. The system appears to have a long orbital period (~7.8 h) accompanied by short timescale variabilities, which we tentatively interpret as the spin and beat periods of an intermediate polar. These short- and long-timescale… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.15429v1-abstract-full').style.display = 'inline'; document.getElementById('2409.15429v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.15429v1-abstract-full" style="display: none;"> We present our findings from the first long X-ray observation of the hard X-ray source Swift J0826.2-7033 with XMM-Newton, which has shown characteristics of magnetic accretion. The system appears to have a long orbital period (~7.8 h) accompanied by short timescale variabilities, which we tentatively interpret as the spin and beat periods of an intermediate polar. These short- and long-timescale modulations are energy-independent, suggesting that photoelectric absorption does not play any role in producing the variabilities. If our suspected spin and beat periods are true, then Swift J0826.2-7033 accretes via disc-overflow with an equal fraction of accretion taking place via disc and stream. The XMM-Newton and Swift-BAT spectral analysis reveals that the post-shock region in Swift J0826.2-7033 has a multi-temperature structure with a maximum temperature of ~43 keV, which is absorbed by a material with an average equivalent hydrogen column density of ~1.6$\times$10$^{22}$ cm$^{-2}$ that partially covers ~27% of the X-ray source. The suprasolar abundances, with hints of an evolved donor, collectively make Swift J0826.2-7033 an interesting target, which likely underwent a thermal timescale mass transfer phase. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.15429v1-abstract-full').style.display = 'none'; document.getElementById('2409.15429v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 7 figures. Accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 691, A264 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.00221">arXiv:2407.00221</a> <span> [<a href="https://arxiv.org/pdf/2407.00221">pdf</a>, <a href="https://arxiv.org/format/2407.00221">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"> Spectro-photometric follow up of the outbursting AM CVn system ASASSN-21br </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Painter%2C+S">S. Painter</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">E. Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Motsoaledi%2C+M">M. Motsoaledi</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">K. V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">J. Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D+A+H">D. A. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Kochanek%2C+C+S">C. S. Kochanek</a>, <a href="/search/astro-ph?searchtype=author&query=Maccarone%2C+T+J">T. J. Maccarone</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Shappee%2C+B+J">B. J. Shappee</a>, <a href="/search/astro-ph?searchtype=author&query=Stanek%2C+K+Z">K. Z. Stanek</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.00221v2-abstract-short" style="display: inline;"> We report on spectroscopic and photometric observations of the AM CVn system ASASSN-21br, which was discovered in outburst by the All-Sky Automated Survey for Supernovae in February 2021. The outburst lasted for around three weeks, and exhibited a pronounced brightness dip for $\approx$ 4 days, during which the spectra showed a sudden transition from emission- to absorption-line dominated. Only… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.00221v2-abstract-full').style.display = 'inline'; document.getElementById('2407.00221v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.00221v2-abstract-full" style="display: none;"> We report on spectroscopic and photometric observations of the AM CVn system ASASSN-21br, which was discovered in outburst by the All-Sky Automated Survey for Supernovae in February 2021. The outburst lasted for around three weeks, and exhibited a pronounced brightness dip for $\approx$ 4 days, during which the spectra showed a sudden transition from emission- to absorption-line dominated. Only $\approx$ 60 AM CVn systems with derived orbital periods are found in the Galaxy, therefore increasing the sample of AM CVn systems with known orbital periods is of tremendous importance to (1) constrain the physical mechanisms of their outbursts and (2) establish a better understanding of the low-frequency background noise of future gravitational wave surveys. Time-resolved photometry taken during the outburst of ASASSN-21br showed modulation with a period of around 36.65 minutes, which is likely the superhump or orbital period of the system. Time-resolved spectroscopy taken with the Southern African Large Telescope did not show any sign of periodicity in the He I absorption lines. This is possibly due to the origin of these lines in the outbursting accretion disc, which makes it challenging to retrieve periodicity from the spectral lines. Future follow up spectral observations during quiescence might allow us better constrain the orbital period of ASASSN-21br. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.00221v2-abstract-full').style.display = 'none'; document.getElementById('2407.00221v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 13 figures, accepted at 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/2405.01508">arXiv:2405.01508</a> <span> [<a href="https://arxiv.org/pdf/2405.01508">pdf</a>, <a href="https://arxiv.org/format/2405.01508">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> Symbiotic stars in X-rays IV: XMM-Newton, Swift and TESS observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lima%2C+I+J">Isabel J. Lima</a>, <a href="/search/astro-ph?searchtype=author&query=Luna%2C+G+J+M">G. Juan M. Luna</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Oliveira%2C+A+S">Alexandre S. Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">Jennifer L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Walter%2C+F">Fred Walter</a>, <a href="/search/astro-ph?searchtype=author&query=Palivanas%2C+N">Natalia Palivanas</a>, <a href="/search/astro-ph?searchtype=author&query=Nu%C3%B1ez%2C+N+E">Natalia E. Nu帽ez</a>, <a href="/search/astro-ph?searchtype=author&query=Souza%2C+R+R">Rafael R. Souza</a>, <a href="/search/astro-ph?searchtype=author&query=Araujo%2C+R+A+N">Rosana A. N. Araujo</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.01508v1-abstract-short" style="display: inline;"> White dwarf symbiotic binaries are detected in X-rays with luminosities in the range of 10$^{30}$ to 10$^{34}$ lumcgs. Their X-ray emission arises either from the accretion disk boundary layer, from a region where the winds from both components collide or from nuclear burning on the white dwarf surface. In our continuous effort to identify X-ray emitting symbiotic stars, we studied four systems us… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.01508v1-abstract-full').style.display = 'inline'; document.getElementById('2405.01508v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.01508v1-abstract-full" style="display: none;"> White dwarf symbiotic binaries are detected in X-rays with luminosities in the range of 10$^{30}$ to 10$^{34}$ lumcgs. Their X-ray emission arises either from the accretion disk boundary layer, from a region where the winds from both components collide or from nuclear burning on the white dwarf surface. In our continuous effort to identify X-ray emitting symbiotic stars, we studied four systems using observations from the Neil Gehrels Swift Observatory and XMM-Newton satellites in X-rays and from TESS in the optical. The X-ray spectra were fit with absorbed optically thin thermal plasma models, either single- or multitemperature with kT $<$ 8 keV for all targets. Based on the characteristics of their X-ray spectra, we classified BD Cam as possible $尾$-type, V1261 Ori and CD -27 8661 as $未$-type, and confirmed NQ Gem as $尾$/$未$-type. The $未$-type X-ray emission most likely arise in the boundary layer of the accretion disk, while in the case of BD Cam, its mostly-soft emission originates from shocks, possibly between the red giant and WD/disk winds. In general, we have found that the observed X-ray emission is powered by accretion at a low accretion rate of about 10$^{-11}$ M$_{\odot}$ yr$^{-1}$. The low ratio of X-ray to optical luminosities, however indicates that the accretion-disk boundary layer is mostly optically thick and tends to emit in the far or extreme UV. The detection of flickering in optical data provides evidence of the existence of an accretion disk. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.01508v1-abstract-full').style.display = 'none'; document.getElementById('2405.01508v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 11 figures and 7 tables, accepted for publication in the Astronomy & Astrophysics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.19170">arXiv:2403.19170</a> <span> [<a href="https://arxiv.org/pdf/2403.19170">pdf</a>, <a href="https://arxiv.org/format/2403.19170">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> X-ray measurement of a high-mass white dwarf and its spin for the intermediate polar IGR J18434-0508 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gerber%2C+J">Julian Gerber</a>, <a href="/search/astro-ph?searchtype=author&query=Hare%2C+J">Jeremy Hare</a>, <a href="/search/astro-ph?searchtype=author&query=Tomsick%2C+J+A">John A. Tomsick</a>, <a href="/search/astro-ph?searchtype=author&query=Coughenour%2C+B+M">Benjamin M. Coughenour</a>, <a href="/search/astro-ph?searchtype=author&query=Shaw%2C+A+W">Aarran W. Shaw</a>, <a href="/search/astro-ph?searchtype=author&query=Clavel%2C+M">Ma茂ca Clavel</a>, <a href="/search/astro-ph?searchtype=author&query=Fornasini%2C+F">Francesca Fornasini</a>, <a href="/search/astro-ph?searchtype=author&query=Halpern%2C+J">Jules Halpern</a>, <a href="/search/astro-ph?searchtype=author&query=Joens%2C+A">Alyson Joens</a>, <a href="/search/astro-ph?searchtype=author&query=Krivonos%2C+R">Roman Krivonos</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="2403.19170v1-abstract-short" style="display: inline;"> IGR J18434-0508 is a Galactic Intermediate Polar (IP) type Cataclysmic Variable (CV) previously classified through optical spectroscopy. The source is already known to have a hard Chandra spectrum. In this paper, we have used follow-up XMM-Newton and NuSTAR observations to measure the white dwarf (WD) mass and spin period. We measure a spin period of P = 304.4 +/- 0.3 s based on the combined MOS1,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.19170v1-abstract-full').style.display = 'inline'; document.getElementById('2403.19170v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.19170v1-abstract-full" style="display: none;"> IGR J18434-0508 is a Galactic Intermediate Polar (IP) type Cataclysmic Variable (CV) previously classified through optical spectroscopy. The source is already known to have a hard Chandra spectrum. In this paper, we have used follow-up XMM-Newton and NuSTAR observations to measure the white dwarf (WD) mass and spin period. We measure a spin period of P = 304.4 +/- 0.3 s based on the combined MOS1, MOS2, and pn light curve. Although this is twice the optical period found previously, we interpret this value to be the true spin period of the WD. The source has an 8 +/- 2% pulsed fraction in the 0.5-10 keV XMM-Newton data and shows strong dips in the soft energy band (0.5-2 keV). The XMM-Newton and NuSTAR joint spectrum is consistent with a thermal bremsstrahlung continuum model with an additional partial covering factor, reflection, and Fe line Gaussian components. Furthermore, we fit the joint spectrum with the post-shock region "ipolar" model which indicates a high WD mass $>$ $\sim$ 1.36 Msun, approaching the Chandrasekhar limit. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.19170v1-abstract-full').style.display = 'none'; document.getElementById('2403.19170v1-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 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 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/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/2311.04903">arXiv:2311.04903</a> <span> [<a href="https://arxiv.org/pdf/2311.04903">pdf</a>, <a href="https://arxiv.org/ps/2311.04903">ps</a>, <a href="https://arxiv.org/format/2311.04903">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> TESS photometry of the nova eruption in V606 Vul: asymmetric photosphere and multiple ejections? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">Kirill V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">Elias Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Malanchev%2C+K">Konstantin Malanchev</a>, <a href="/search/astro-ph?searchtype=author&query=Burke%2C+C+J">Colin J. Burke</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">J. L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Metzger%2C+B+D">Brian D. Metzger</a>, <a href="/search/astro-ph?searchtype=author&query=Atapin%2C+K+E">Kirill E. Atapin</a>, <a href="/search/astro-ph?searchtype=author&query=Belinski%2C+A+A">Aleksandre A. Belinski</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Y">Yu-Ching Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Dubovsky%2C+P+A">Pavol A. Dubovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Faucher-Giguere%2C+C">Claude-Andre Faucher-Giguere</a>, <a href="/search/astro-ph?searchtype=author&query=Hounsell%2C+R+A">Rebekah A. Hounsell</a>, <a href="/search/astro-ph?searchtype=author&query=Ikonnikova%2C+N+P">Natalia P. Ikonnikova</a>, <a href="/search/astro-ph?searchtype=author&query=Lander%2C+V+Y">Vsevolod Yu. Lander</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+J">Junyao Li</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">Justin D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=Mioduszewski%2C+A+J">Amy J. Mioduszewski</a>, <a href="/search/astro-ph?searchtype=author&query=Molina%2C+I">Isabella Molina</a>, <a href="/search/astro-ph?searchtype=author&query=Munari%2C+U">Ulisse Munari</a>, <a href="/search/astro-ph?searchtype=author&query=Potanin%2C+S+A">Sergey A. Potanin</a>, <a href="/search/astro-ph?searchtype=author&query=Quimby%2C+R+M">Robert M. Quimby</a>, <a href="/search/astro-ph?searchtype=author&query=Rupen%2C+M+P">Michael P. Rupen</a>, <a href="/search/astro-ph?searchtype=author&query=Scaringi%2C+S">Simone Scaringi</a> , et al. (46 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2311.04903v1-abstract-short" style="display: inline;"> Lightcurves of many classical novae deviate from the canonical "fast rise - smooth decline" pattern and display complex variability behavior. We present the first TESS-space-photometry-based investigation of this phenomenon. We use TESS Sector 41 full-frame images to extract a lightcurve of the slow Galactic nova V606 Vul that erupted nine days prior to the start of the TESS observations. The ligh… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04903v1-abstract-full').style.display = 'inline'; document.getElementById('2311.04903v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.04903v1-abstract-full" style="display: none;"> Lightcurves of many classical novae deviate from the canonical "fast rise - smooth decline" pattern and display complex variability behavior. We present the first TESS-space-photometry-based investigation of this phenomenon. We use TESS Sector 41 full-frame images to extract a lightcurve of the slow Galactic nova V606 Vul that erupted nine days prior to the start of the TESS observations. The lightcurve covers the first of two major peaks of V606 Vul that was reached 19 days after the start of the eruption. The nova reached its brightest visual magnitude V=9.9 in its second peak 64 days after the eruption onset, following the completion of Sector 41 observations. To increase the confidence level of the extracted lightcurve, we performed the analysis using four different codes implementing the aperture photometry (Lightkurve, VaST) and image subtraction (TESSreduce, tequila_shots) and find good agreement between them. We performed ground-based photometric and spectroscopic monitoring to complement the TESS data. The TESS lightcurve reveals two features: periodic variations (0.12771d, 0.01mag average peak-to-peak amplitude) that disappeared when the source was within 1mag of peak optical brightness and a series of isolated mini-flares (with peak-to-peak amplitudes of up to 0.5mag) appearing at seemingly random times. We interpret the periodic variations as the result of azimuthal asymmetry of the photosphere engulfing the nova-hosting binary that was distorted by and rotating with the binary. Whereas we use spectra to associate the two major peaks in the nova lightcurve with distinct episodes of mass ejection, the origin of mini-flares remains elusive. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04903v1-abstract-full').style.display = 'none'; document.getElementById('2311.04903v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">31 pages, 10 figures, submitted to ApJ; comments 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/2309.11288">arXiv:2309.11288</a> <span> [<a href="https://arxiv.org/pdf/2309.11288">pdf</a>, <a href="https://arxiv.org/format/2309.11288">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202346997">10.1051/0004-6361/202346997 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Transient and asymmetric dust structures in the TeV-bright nova RS Oph revealed by spectropolarimetry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nikolov%2C+Y">Y. Nikolov</a>, <a href="/search/astro-ph?searchtype=author&query=Luna%2C+G+J+M">G. J. M. Luna</a>, <a href="/search/astro-ph?searchtype=author&query=Stoyanov%2C+K+A">K. A. Stoyanov</a>, <a href="/search/astro-ph?searchtype=author&query=Borisov%2C+G">G. Borisov</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">J. L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Avramova-Boncheva%2C+A">A. Avramova-Boncheva</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="2309.11288v1-abstract-short" style="display: inline;"> A long-standing question related to nova eruptions is how these eruptions can lead to the formation of dust despite the ostensibly inhospitable environment for dust within the hot, irradiated ejecta. Novae in systems such as the symbiotic binary RS Oph offers a articularly clear view of some nova shocks and any associated dust production. Here we use spectropolarimetric monitoring of the RS Oph st… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.11288v1-abstract-full').style.display = 'inline'; document.getElementById('2309.11288v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.11288v1-abstract-full" style="display: none;"> A long-standing question related to nova eruptions is how these eruptions can lead to the formation of dust despite the ostensibly inhospitable environment for dust within the hot, irradiated ejecta. Novae in systems such as the symbiotic binary RS Oph offers a articularly clear view of some nova shocks and any associated dust production. Here we use spectropolarimetric monitoring of the RS Oph starting two days after its eruption in 2021 Aug. to show that: dust was present in the RS Oph system as early as two days into the 2021 eruption; the spatial distribution of this early dust was asymmetric, with components both aligned with and perpendicular to the orbital plane of the binary; between two and nine days after the start of the eruption, this early dust was gradually destroyed; and dust was again created, aligned roughly with the orbital plane of the binary, more than 80 days after the start of the outburst, most likely as a result of shocks that arose as the ejecta interacted with circumbinary material concentrated in the orbital plane. Modelling of X-rays and very-high energy GeV and TeV emission from RS Oph days to months into the 2021 eruption suggests that collisions between the ejecta and the circumbinary material may have led to shock formation in two regions: the polar - perpendicular to the orbital plane where collimated outflows have been observed after prior eruptions, and a circumbinary torus in the orbital plane. The observations described here indicate that dust formed in approximately the same two regions, supporting the connection between shocks and dust in novae and revealing a very early onset of asymmetry. The spectropolarimetric signatures of RS Oph in the first week into the 2021 outburst indicate: polarized flux across the H伪 emission line and position angle orientation relative to the radio axis are similar to the spectropolarimetric signatures of AGNs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.11288v1-abstract-full').style.display = 'none'; document.getElementById('2309.11288v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">9 pages, 10 figures, 1 table, resubmitted to the Astronomy & Astrophysics after the first reviewer's report</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 679, A150 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.07097">arXiv:2309.07097</a> <span> [<a href="https://arxiv.org/pdf/2309.07097">pdf</a>, <a href="https://arxiv.org/format/2309.07097">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> Revisiting the classics: On the evolutionary origin of the "Fe II" and "He/N" spectral classes of novae </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">E. Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">L. Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">J. Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">K. V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+R+E">R. E. Williams</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D+A+H">D. A. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Ederoclite%2C+A">A. Ederoclite</a>, <a href="/search/astro-ph?searchtype=author&query=Izzo%2C+L">L. Izzo</a>, <a href="/search/astro-ph?searchtype=author&query=Kyer%2C+R">R. Kyer</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">J. D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=Kniazev%2C+A">A. Kniazev</a>, <a href="/search/astro-ph?searchtype=author&query=Metzger%2C+B+D">B. D. Metzger</a>, <a href="/search/astro-ph?searchtype=author&query=Mikolajewska%2C+J">J. Mikolajewska</a>, <a href="/search/astro-ph?searchtype=author&query=Molaro%2C+P">P. Molaro</a>, <a href="/search/astro-ph?searchtype=author&query=Mollina%2C+I">I. Mollina</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Munari%2C+U">U. Munari</a>, <a href="/search/astro-ph?searchtype=author&query=Orio%2C+M">M. Orio</a>, <a href="/search/astro-ph?searchtype=author&query=Panurach%2C+T">T. Panurach</a>, <a href="/search/astro-ph?searchtype=author&query=Shappee%2C+B+J">B. J. Shappee</a>, <a href="/search/astro-ph?searchtype=author&query=Shen%2C+K+J">K. J. Shen</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">J. L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Urquhart%2C+R">R. Urquhart</a>, <a href="/search/astro-ph?searchtype=author&query=Walter%2C+F+M">F. M. Walter</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="2309.07097v2-abstract-short" style="display: inline;"> The optical spectra of novae are characterized by emission lines from the hydrogen Balmer series and either Fe II or He/N, leading to their traditional classification into two spectral classes: "Fe II" and "He/N". For decades, the origins of these spectral features were discussed in the literature in the contexts of different bodies of gas or changes in the opacity of the ejecta, particularly asso… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.07097v2-abstract-full').style.display = 'inline'; document.getElementById('2309.07097v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.07097v2-abstract-full" style="display: none;"> The optical spectra of novae are characterized by emission lines from the hydrogen Balmer series and either Fe II or He/N, leading to their traditional classification into two spectral classes: "Fe II" and "He/N". For decades, the origins of these spectral features were discussed in the literature in the contexts of different bodies of gas or changes in the opacity of the ejecta, particularly associated with studies by R. E. Williams and S. N. Shore. Here, we revisit these major studies with dedicated, modern data sets, covering the evolution of several novae from early rise to peak all the way to the nebular phase. Our data confirm previous suggestions in the literature that the "Fe II" and "He/N" spectral classes are phases in the spectroscopic evolution of novae driven primarily by changes in the opacity, ionization, and density of the ejecta, and most if not all novae go through at least three spectroscopic phases as their eruptions evolve: an early He/N (phase 1; observed during the early rise to visible peak and characterized by P Cygni lines of He I, N II, and N III), then an Fe II (phase 2; observed near visible peak and characterized by P Cygni lines of Fe II and O I), and then a later He/N (phase 3; observed during the decline and characterized by emission lines of He I. He II, N II, and N III), before entering the nebular phase. This spectral evolution seems to be ubiquitous across novae, regardless of their speed class; however the duration of each of these phase differs based on the speed class of the nova. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.07097v2-abstract-full').style.display = 'none'; document.getElementById('2309.07097v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">21 pages, 14 figures, 11 tables, Accepted 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/2309.04374">arXiv:2309.04374</a> <span> [<a href="https://arxiv.org/pdf/2309.04374">pdf</a>, <a href="https://arxiv.org/format/2309.04374">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> A broadband X-ray study of the dwarf nova SS Cyg during quiescence and outburst </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dutta%2C+A">Anirban Dutta</a>, <a href="/search/astro-ph?searchtype=author&query=Rana%2C+V">Vikram Rana</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=de+Oliveira%2C+R+L">Raimundo Lopes de Oliveira</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="2309.04374v1-abstract-short" style="display: inline;"> We present a broadband X-ray study ($\sim$\,0.3-50 keV) of the dwarf nova SS Cyg highlighting the changes in the accretion during two phases, the quiescence and the outburst states. The investigation was based on simultaneous observations carried out with the XMM-Newton and NuSTAR telescopes in two epochs, involving medium and high-resolution spectroscopy. Spectra were harder during quiescence (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.04374v1-abstract-full').style.display = 'inline'; document.getElementById('2309.04374v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.04374v1-abstract-full" style="display: none;"> We present a broadband X-ray study ($\sim$\,0.3-50 keV) of the dwarf nova SS Cyg highlighting the changes in the accretion during two phases, the quiescence and the outburst states. The investigation was based on simultaneous observations carried out with the XMM-Newton and NuSTAR telescopes in two epochs, involving medium and high-resolution spectroscopy. Spectra were harder during quiescence ($kT_{\rm high}\sim22.8$ keV) than outburst ($kT_{\rm high}\sim8.4$ keV), while the mass accretion rate increased by $\sim35$ times in outburst ($1.7\times10^{16} \rm g\;s^{-1}$) than quiescence. The bolometric luminosity (0.01-100.0 keV) during the outburst was dominated by a blackbody emission ($kT_{\rm BB}\sim28$ eV) from the optically thick boundary layer, and the inner edge of the accretion disk resides very close to the WD surface. X-rays from the accretion disk boundary layer are consistent with the white dwarf having mass $1.18_{-0.01}^{+0.02} \rm M_{\odot}$. Our study conclusively confirms the presence of the reflection hump in the 10-30 keV range for both phases, which arises when X-ray photons hit colder material and undergo Compton scattering. We estimated a similarly strong reflection amplitude during quiescence ($\sim1.25$) and outburst ($\sim1.31$), indicating both the WD surface and disk are contributing to reflection. The neutral Fe K$_伪$ line, which is correlated with Compton reflection, also showed similar strength ($\sim80$ eV) in both phases. Finally, X-rays also revealed the presence of a partial intrinsic absorber during the outburst, possibly due to an outflowing accretion disk wind. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.04374v1-abstract-full').style.display = 'none'; document.getElementById('2309.04374v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">14 pages, 5 figures, 4 tables, Accepted for publication in The Astrophysical Journal (ApJ)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.13959">arXiv:2307.13959</a> <span> [<a href="https://arxiv.org/pdf/2307.13959">pdf</a>, <a href="https://arxiv.org/format/2307.13959">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <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"> Swift Deep Galactic Plane Survey Classification of Swift J170800$-$402551.8 as a Candidate Intermediate Polar Cataclysmic Variable </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=O%27Connor%2C+B">B. O'Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Gogus%2C+E">E. Gogus</a>, <a href="/search/astro-ph?searchtype=author&query=Hare%2C+J">J. Hare</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Huppenkothen%2C+D">D. Huppenkothen</a>, <a href="/search/astro-ph?searchtype=author&query=Brink%2C+J">J. Brink</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D+A+H">D. A. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Levan%2C+A">A. Levan</a>, <a href="/search/astro-ph?searchtype=author&query=Baring%2C+M+G">M. G. Baring</a>, <a href="/search/astro-ph?searchtype=author&query=Stewart%2C+R">R. Stewart</a>, <a href="/search/astro-ph?searchtype=author&query=Kouveliotou%2C+C">C. Kouveliotou</a>, <a href="/search/astro-ph?searchtype=author&query=Woudt%2C+P">P. Woudt</a>, <a href="/search/astro-ph?searchtype=author&query=Bellm%2C+E">E. Bellm</a>, <a href="/search/astro-ph?searchtype=author&query=Cenko%2C+S+B">S. B. Cenko</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+P+A">P. A. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Granot%2C+J">J. Granot</a>, <a href="/search/astro-ph?searchtype=author&query=Hailey%2C+C">C. Hailey</a>, <a href="/search/astro-ph?searchtype=author&query=Harrison%2C+F">F. Harrison</a>, <a href="/search/astro-ph?searchtype=author&query=Hartmann%2C+D">D. Hartmann</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Horst%2C+A+J">A. J. van der Horst</a>, <a href="/search/astro-ph?searchtype=author&query=Kaper%2C+L">L. Kaper</a>, <a href="/search/astro-ph?searchtype=author&query=Kennea%2C+J+A">J. A. Kennea</a>, <a href="/search/astro-ph?searchtype=author&query=Potter%2C+S+B">S. B. Potter</a>, <a href="/search/astro-ph?searchtype=author&query=Slane%2C+P+O">P. O. Slane</a>, <a href="/search/astro-ph?searchtype=author&query=Stern%2C+D">D. Stern</a> , et al. (2 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2307.13959v3-abstract-short" style="display: inline;"> Here, we present the results of our multi-wavelength campaign aimed at classifying \textit{Swift} J170800$-$402551.8 as part of the \textit{Swift} Deep Galactic Plane Survey (DGPS). We utilized Target of Opportunity (ToO) observations with \textit{Swift}, \textit{NICER}, \textit{XMM-Newton}, \textit{NuSTAR}, and the Southern African Large Telescope (SALT), as well as multi-wavelength archival obse… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.13959v3-abstract-full').style.display = 'inline'; document.getElementById('2307.13959v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.13959v3-abstract-full" style="display: none;"> Here, we present the results of our multi-wavelength campaign aimed at classifying \textit{Swift} J170800$-$402551.8 as part of the \textit{Swift} Deep Galactic Plane Survey (DGPS). We utilized Target of Opportunity (ToO) observations with \textit{Swift}, \textit{NICER}, \textit{XMM-Newton}, \textit{NuSTAR}, and the Southern African Large Telescope (SALT), as well as multi-wavelength archival observations from \textit{Gaia}, VPHAS, and VVV. The source displays a periodicity of 784 s in our \textit{XMM-Newton} observation. The X-ray spectrum (\textit{XMM-Newton} and \textit{NuSTAR}) can be described by thermal bremsstrahlung radiation with a temperature of $kT$\,$\approx$\,$30$ keV. The phase-folded X-ray lightcurve displays a double-peaked, energy-dependent pulse-profile. We used \textit{Chandra} to precisely localize the source, allowing us to identify and study the multi-wavelength counterpart. Spectroscopy with SALT identified a Balmer H$伪$ line, and potential HeI lines, from the optical counterpart. The faintness of the counterpart ($r$\,$\approx$\,$21$ AB mag) favors a low-mass donor star. Based on these criteria, we classify \textit{Swift} J170800$-$402551.8 as a candidate intermediate polar cataclysmic variable, where the spin period of the white dwarf is 784 s. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.13959v3-abstract-full').style.display = 'none'; document.getElementById('2307.13959v3-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 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted 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/2306.14354">arXiv:2306.14354</a> <span> [<a href="https://arxiv.org/pdf/2306.14354">pdf</a>, <a href="https://arxiv.org/format/2306.14354">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> The Swift Deep Galactic Plane Survey (DGPS) Phase-I Catalog </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=O%27Connor%2C+B">B. O'Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Kouveliotou%2C+C">C. Kouveliotou</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+P+A">P. A. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Gorgone%2C+N">N. Gorgone</a>, <a href="/search/astro-ph?searchtype=author&query=van+Kooten%2C+A+J">A. J. van Kooten</a>, <a href="/search/astro-ph?searchtype=author&query=Gagnon%2C+S">S. Gagnon</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+H">H. Yang</a>, <a href="/search/astro-ph?searchtype=author&query=Baring%2C+M+G">M. G. Baring</a>, <a href="/search/astro-ph?searchtype=author&query=Bellm%2C+E">E. Bellm</a>, <a href="/search/astro-ph?searchtype=author&query=Beniamini%2C+P">P. Beniamini</a>, <a href="/search/astro-ph?searchtype=author&query=Brink%2C+J">J. Brink</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D+A+H">D. A. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Cenko%2C+S+B">S. B. Cenko</a>, <a href="/search/astro-ph?searchtype=author&query=Egbo%2C+O+D">O. D. Egbo</a>, <a href="/search/astro-ph?searchtype=author&query=Gogus%2C+E">E. Gogus</a>, <a href="/search/astro-ph?searchtype=author&query=Granot%2C+J">J. Granot</a>, <a href="/search/astro-ph?searchtype=author&query=Hailey%2C+C">C. Hailey</a>, <a href="/search/astro-ph?searchtype=author&query=Hare%2C+J">J. Hare</a>, <a href="/search/astro-ph?searchtype=author&query=Harrison%2C+F">F. Harrison</a>, <a href="/search/astro-ph?searchtype=author&query=Hartmann%2C+D">D. Hartmann</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Horst%2C+A+J">A. J. van der Horst</a>, <a href="/search/astro-ph?searchtype=author&query=Huppenkothen%2C+D">D. Huppenkothen</a>, <a href="/search/astro-ph?searchtype=author&query=Kaper%2C+L">L. Kaper</a>, <a href="/search/astro-ph?searchtype=author&query=Kargaltsev%2C+O">O. Kargaltsev</a>, <a href="/search/astro-ph?searchtype=author&query=Kennea%2C+J+A">J. A. Kennea</a> , et al. (8 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.14354v3-abstract-short" style="display: inline;"> The \textit{Swift} Deep Galactic Plane Survey is a \textit{Swift} Key Project consisting of 380 tiled pointings covering 40 deg$^{2}$ of the Galactic Plane between longitude $10$\,$<$\,$|l|$\,$<$\,$30$ deg and latitude $|b|$\,$<$\,$0.5$ deg. Each pointing has a $5$ ks exposure, yielding a total of 1.9 Ms spread across the entire survey footprint. Phase-I observations were carried out between March… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.14354v3-abstract-full').style.display = 'inline'; document.getElementById('2306.14354v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.14354v3-abstract-full" style="display: none;"> The \textit{Swift} Deep Galactic Plane Survey is a \textit{Swift} Key Project consisting of 380 tiled pointings covering 40 deg$^{2}$ of the Galactic Plane between longitude $10$\,$<$\,$|l|$\,$<$\,$30$ deg and latitude $|b|$\,$<$\,$0.5$ deg. Each pointing has a $5$ ks exposure, yielding a total of 1.9 Ms spread across the entire survey footprint. Phase-I observations were carried out between March 2017 and May 2021. The Survey is complete to depth $L_X$\,$>$\,$10^{34}$ erg s$^{-1}$ to the edge of the Galaxy. The main Survey goal is to produce a rich sample of new X-ray sources and transients, while also covering a broad discovery space. Here, we introduce the Survey strategy and present a catalog of sources detected during Phase-I observations. In total, we identify 928 X-ray sources, of which 348 are unique to our X-ray catalog. We report on the characteristics of sources in our catalog and highlight sources newly classified and published by the DGPS team. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.14354v3-abstract-full').style.display = 'none'; document.getElementById('2306.14354v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted in ApJS. This is the final version</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.05576">arXiv:2306.05576</a> <span> [<a href="https://arxiv.org/pdf/2306.05576">pdf</a>, <a href="https://arxiv.org/format/2306.05576">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"> Identification of 1RXS J165424.6-433758 as a polar cataclysmic variable </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=O%27Connor%2C+B">B. O'Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Brink%2C+J">J. Brink</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D+A+H">D. A. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Kouveliotou%2C+C">C. Kouveliotou</a>, <a href="/search/astro-ph?searchtype=author&query=Gogus%2C+E">E. Gogus</a>, <a href="/search/astro-ph?searchtype=author&query=Potter%2C+S+B">S. B. Potter</a>, <a href="/search/astro-ph?searchtype=author&query=Woudt%2C+P">P. Woudt</a>, <a href="/search/astro-ph?searchtype=author&query=Lien%2C+A">A. Lien</a>, <a href="/search/astro-ph?searchtype=author&query=Levan%2C+A">A. Levan</a>, <a href="/search/astro-ph?searchtype=author&query=Kargaltsev%2C+O">O. Kargaltsev</a>, <a href="/search/astro-ph?searchtype=author&query=Baring%2C+M+G">M. G. Baring</a>, <a href="/search/astro-ph?searchtype=author&query=Bellm%2C+E">E. Bellm</a>, <a href="/search/astro-ph?searchtype=author&query=Cenko%2C+S+B">S. B. Cenko</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+P+A">P. A. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Granot%2C+J">J. Granot</a>, <a href="/search/astro-ph?searchtype=author&query=Hailey%2C+C">C. Hailey</a>, <a href="/search/astro-ph?searchtype=author&query=Harrison%2C+F">F. Harrison</a>, <a href="/search/astro-ph?searchtype=author&query=Hartmann%2C+D">D. Hartmann</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Horst%2C+A+J">A. J. van der Horst</a>, <a href="/search/astro-ph?searchtype=author&query=Huppenkothen%2C+D">D. Huppenkothen</a>, <a href="/search/astro-ph?searchtype=author&query=Kaper%2C+L">L. Kaper</a>, <a href="/search/astro-ph?searchtype=author&query=Kennea%2C+J+A">J. A. Kennea</a>, <a href="/search/astro-ph?searchtype=author&query=Slane%2C+P+O">P. O. Slane</a>, <a href="/search/astro-ph?searchtype=author&query=Stern%2C+D">D. Stern</a> , et al. (3 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.05576v2-abstract-short" style="display: inline;"> We present the results of our X-ray, ultraviolet, and optical follow-up campaigns of 1RXS J165424.6-433758, an X-ray source detected with the \textit{Swift} Deep Galactic Plane Survey (DGPS). The source X-ray spectrum (\textit{Swift} and \textit{NuSTAR}) is described by thermal bremsstrahlung radiation with a temperature of $kT=10.1\pm1.2$ keV, yielding an X-ray ($0.3-10$ keV) luminosity… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.05576v2-abstract-full').style.display = 'inline'; document.getElementById('2306.05576v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.05576v2-abstract-full" style="display: none;"> We present the results of our X-ray, ultraviolet, and optical follow-up campaigns of 1RXS J165424.6-433758, an X-ray source detected with the \textit{Swift} Deep Galactic Plane Survey (DGPS). The source X-ray spectrum (\textit{Swift} and \textit{NuSTAR}) is described by thermal bremsstrahlung radiation with a temperature of $kT=10.1\pm1.2$ keV, yielding an X-ray ($0.3-10$ keV) luminosity $L_X=(6.5\pm0.8)\times10^{31}$ erg s$^{-1}$ at a \textit{Gaia} distance of 460 pc. Spectroscopy with the Southern African Large Telescope (SALT) revealed a flat continuum dominated by emission features, demonstrating an inverse Balmer decrement, the $\lambda4640$ Bowen blend, almost a dozen HeI lines, and HeII $\lambda4541$, $\lambda4686$ and $位5411$. Our high-speed photometry demonstrates a preponderance of flickering and flaring episodes, and revealed the orbital period of the system, $P_\textrm{orb}=2.87$ hr, which fell well within the cataclysmic variable (CV) period gap between $2-3$ hr. These features classify 1RXS J165424.6-433758 as a nearby polar magnetic CV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.05576v2-abstract-full').style.display = 'none'; document.getElementById('2306.05576v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted 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/2306.04691">arXiv:2306.04691</a> <span> [<a href="https://arxiv.org/pdf/2306.04691">pdf</a>, <a href="https://arxiv.org/format/2306.04691">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stad1729">10.1093/mnras/stad1729 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Classifying IGR J15038-6021 as a magnetic CV with a massive white dwarf </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Tomsick%2C+J+A">John A. Tomsick</a>, <a href="/search/astro-ph?searchtype=author&query=Kumar%2C+S+G">Snehaa Ganesh Kumar</a>, <a href="/search/astro-ph?searchtype=author&query=Coughenour%2C+B+M">Benjamin M. Coughenour</a>, <a href="/search/astro-ph?searchtype=author&query=Shaw%2C+A+W">Aarran W. Shaw</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Hare%2C+J">Jeremy Hare</a>, <a href="/search/astro-ph?searchtype=author&query=Clavel%2C+M">Maica Clavel</a>, <a href="/search/astro-ph?searchtype=author&query=Krivonos%2C+R">Roman Krivonos</a>, <a href="/search/astro-ph?searchtype=author&query=Fornasini%2C+F+M">Francesca M. Fornasini</a>, <a href="/search/astro-ph?searchtype=author&query=Gerber%2C+J">Julian Gerber</a>, <a href="/search/astro-ph?searchtype=author&query=Joens%2C+A">Alyson Joens</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="2306.04691v1-abstract-short" style="display: inline;"> Cataclysmic variables (CVs) are binary systems consisting of a white dwarf (WD) accreting matter from a companion star. Observations of CVs provide an opportunity to learn about accretion disks, the physics of compact objects, classical novae, and the evolution of the binary and the WD that may ultimately end in a type Ia supernova (SN). As type Ia SNe involve a WD reaching the Chandrasekhar limit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.04691v1-abstract-full').style.display = 'inline'; document.getElementById('2306.04691v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.04691v1-abstract-full" style="display: none;"> Cataclysmic variables (CVs) are binary systems consisting of a white dwarf (WD) accreting matter from a companion star. Observations of CVs provide an opportunity to learn about accretion disks, the physics of compact objects, classical novae, and the evolution of the binary and the WD that may ultimately end in a type Ia supernova (SN). As type Ia SNe involve a WD reaching the Chandrasekhar limit or merging WDs, WD mass measurements are particularly important for elucidating the path from CV to type Ia SN. For intermediate polar (IP) type CVs, the WD mass is related to the bremsstrahlung temperature of material in the accretion column, which typically peaks at X-ray energies. Thus, the IPs with the strongest hard X-ray emission, such as those discovered by the INTEGRAL satellite, are expected to have the highest masses. Here, we report on XMM-Newton, NuSTAR, and optical observations of IGR J15038-6021. We find an X-ray periodicity of 1678+/-2s, which we interpret as the WD spin period. From fitting the 0.3-79 keV spectrum with a model that uses the relationship between the WD mass and the post-shock temperature, we measure a WD mass of 1.36+0.04-0.11 Msun. This follows an earlier study of IGR J14091-6108, which also has a WD with a mass approaching the Chandrasekhar limit. We demonstrate that these are both outliers among IPs in having massive WDs and discuss the results in the context of WD mass studies as well as the implications for WD mass evolution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.04691v1-abstract-full').style.display = 'none'; document.getElementById('2306.04691v1-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 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted 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/2305.15494">arXiv:2305.15494</a> <span> [<a href="https://arxiv.org/pdf/2305.15494">pdf</a>, <a href="https://arxiv.org/ps/2305.15494">ps</a>, <a href="https://arxiv.org/format/2305.15494">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/stad1603">10.1093/mnras/stad1603 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Orbital Period vs. Absolute Magnitude Relationship of Intermediate Polars: Implications for Low States and Outbursts </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Pretorius%2C+M+L">Magaretha L. Pretorius</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="2305.15494v1-abstract-short" style="display: inline;"> Recent advances in time-domain astronomy have led to fresh observational insights into intermediate polars, a subtype of magnetic cataclysmic variables generally accreting via a partial accretion disc. These new discoveries include detections of superhumps, low states, and outbursts. However, these studies have largely relied on relative photometry. Here we tabulate the absolute G magnitudes of co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.15494v1-abstract-full').style.display = 'inline'; document.getElementById('2305.15494v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.15494v1-abstract-full" style="display: none;"> Recent advances in time-domain astronomy have led to fresh observational insights into intermediate polars, a subtype of magnetic cataclysmic variables generally accreting via a partial accretion disc. These new discoveries include detections of superhumps, low states, and outbursts. However, these studies have largely relied on relative photometry. Here we tabulate the absolute G magnitudes of confirmed intermediate polars, plot them against their orbital periods, and compare the results to similar studies of dwarf novae during quiescence and in outburst. This exercise suggests the presence of two distinct luminosity classes of intermediate polars, with practical and physical implications for the studies of low states and outbursts. In particular, we point out that two of the optically luminous systems showing short outbursts are also seen to exhibit superhumps, suggesting that they may be caused by the same underlying mechanism. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.15494v1-abstract-full').style.display = 'none'; document.getElementById('2305.15494v1-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages including 4 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.01496">arXiv:2305.01496</a> <span> [<a href="https://arxiv.org/pdf/2305.01496">pdf</a>, <a href="https://arxiv.org/ps/2305.01496">ps</a>, <a href="https://arxiv.org/format/2305.01496">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/acd001">10.3847/1538-4357/acd001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gravitational Redshift Detection from the Magnetic White Dwarf Harbored in RX J1712.6-2414 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hayashi%2C+T">Takayuki Hayashi</a>, <a href="/search/astro-ph?searchtype=author&query=Mori%2C+H">Hideyuki Mori</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Terada%2C+Y">Yukikatsu Terada</a>, <a href="/search/astro-ph?searchtype=author&query=Ishida%2C+M">Manabu Ishida</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="2305.01496v1-abstract-short" style="display: inline;"> Gravitational redshift is a fundamental parameter that allows us to determine the mass-to-radius ratio of compact stellar objects, such as black holes, neutron stars, and white dwarfs (WDs). In the X-ray spectra of the close binary system, RX J1712.6$-$2414, obtained from the Chandra High-Energy Transmission Grating observation, we detected significant redshifts for characteristic X-rays emitted f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.01496v1-abstract-full').style.display = 'inline'; document.getElementById('2305.01496v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.01496v1-abstract-full" style="display: none;"> Gravitational redshift is a fundamental parameter that allows us to determine the mass-to-radius ratio of compact stellar objects, such as black holes, neutron stars, and white dwarfs (WDs). In the X-ray spectra of the close binary system, RX J1712.6$-$2414, obtained from the Chandra High-Energy Transmission Grating observation, we detected significant redshifts for characteristic X-rays emitted from hydrogen-like magnesium, silicon ($螖E/E_{\rm rest} \sim 7 \times 10^{-4}$), and sulfur ($螖E/E_{\rm rest} \sim 15 \times 10^{-4}$) ions, which are over the instrumental absolute energy accuracy (${螖E/E_{\rm rest} \sim 3.3} \times 10^{-4}$). Considering some possible factors, such as Doppler shifts associated with the plasma flow, systemic velocity, and optical depth, we concluded that the major contributor to the observed redshift is the gravitational redshift of the WD harbored in the binary system, which is the first gravitational redshift detection from a magnetic WD. Moreover, the gravitational redshift provides us with a new method of the WD mass measurement by invoking the plasma-flow theory with strong magnetic fields in close binaries. Regardless of large uncertainty, our new method estimated the WD mass to be $M_{\rm WD}> 0.9\,M_{\odot}$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.01496v1-abstract-full').style.display = 'none'; document.getElementById('2305.01496v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 5 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/2304.04306">arXiv:2304.04306</a> <span> [<a href="https://arxiv.org/pdf/2304.04306">pdf</a>, <a href="https://arxiv.org/format/2304.04306">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stad1914">10.1093/mnras/stad1914 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Catching a nova X-ray/UV flash in the visible? Early spectroscopy of the extremely slow Nova Velorum 2022 (Gaia22alz) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">E. Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">L. Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Miko%C5%82ajewska%2C+J">J. Miko艂ajewska</a>, <a href="/search/astro-ph?searchtype=author&query=Brink%2C+J">J. Brink</a>, <a href="/search/astro-ph?searchtype=author&query=Metzger%2C+B+D">B. D. Metzger</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">J. Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D+A+H">D. A. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Harvey%2C+E+J">E. J. Harvey</a>, <a href="/search/astro-ph?searchtype=author&query=Holoien%2C+T+W+-">T. W. -S. Holoien</a>, <a href="/search/astro-ph?searchtype=author&query=Izzo%2C+L">L. Izzo</a>, <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">A. Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">J. D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=Molaro%2C+P">P. Molaro</a>, <a href="/search/astro-ph?searchtype=author&query=Mollina%2C+B">B. Mollina</a>, <a href="/search/astro-ph?searchtype=author&query=Mr%C3%B3z%2C+P">P. Mr贸z</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Orio%2C+M">M. Orio</a>, <a href="/search/astro-ph?searchtype=author&query=Panurach%2C+T">T. Panurach</a>, <a href="/search/astro-ph?searchtype=author&query=Senchyna%2C+P">P. Senchyna</a>, <a href="/search/astro-ph?searchtype=author&query=Shappee%2C+B+J">B. J. Shappee</a>, <a href="/search/astro-ph?searchtype=author&query=Shen%2C+K+J">K. J. Shen</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">J. L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">K. V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Urquhart%2C+R">R. Urquhart</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+R+E">R. E. Williams</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="2304.04306v1-abstract-short" style="display: inline;"> We present early spectral observations of the very slow Galactic nova Gaia22alz, over its gradual rise to peak brightness that lasted 180 days. During the first 50 days, when the nova was only 3--4 magnitudes above its normal brightness, the spectra showed narrow (FWHM $\approx$ 400 km s$^{-1}$) emission lines of H Balmer, He I, He II, and C IV, but no P Cygni absorption. A few weeks later, the hi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.04306v1-abstract-full').style.display = 'inline'; document.getElementById('2304.04306v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.04306v1-abstract-full" style="display: none;"> We present early spectral observations of the very slow Galactic nova Gaia22alz, over its gradual rise to peak brightness that lasted 180 days. During the first 50 days, when the nova was only 3--4 magnitudes above its normal brightness, the spectra showed narrow (FWHM $\approx$ 400 km s$^{-1}$) emission lines of H Balmer, He I, He II, and C IV, but no P Cygni absorption. A few weeks later, the high-excitation He II and C IV lines disappeared, and P Cygni profiles of Balmer, He I, and eventually Fe II lines emerged, yielding a spectrum typical of classical novae before peak. We propose that the early spectra of Gaia22alz are produced in the white dwarf's envelope or accretion disk, reprocessing X-ray and ultraviolet emission from the white dwarf after a dramatic increase in the rate of thermonuclear reactions, during a phase known as the ``early X-ray/UV flash''. If true, this would be one of the rare times that the optical signature of the early X-ray/UV flash has been detected. While this phase might last only a few hours in other novae and thus be easily missed, it was possible to detect in Gaia22alz due to its very slow and gradual rise and thanks to the efficiency of new all-sky surveys in detecting transients on their rise. We also consider alternative scenarios that could explain the early spectral features of Gaia22alz and its unusually slow rise. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.04306v1-abstract-full').style.display = 'none'; document.getElementById('2304.04306v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">20 pages, 12 figures, 2 tables. Submitted to MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.03043">arXiv:2302.03043</a> <span> [<a href="https://arxiv.org/pdf/2302.03043">pdf</a>, <a href="https://arxiv.org/ps/2302.03043">ps</a>, <a href="https://arxiv.org/format/2302.03043">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/stad887">10.1093/mnras/stad887 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The multi-wavelength view of shocks in the fastest nova V1674 Her </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">K. V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+T+J">T. J. Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Buson%2C+S">S. Buson</a>, <a href="/search/astro-ph?searchtype=author&query=Jean%2C+P">P. Jean</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+C+C">C. C. Cheung</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">L. Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">E. Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Molina%2C+B">B. Molina</a>, <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">A. Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">J. D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=Mioduszewski%2C+A+J">A. J. Mioduszewski</a>, <a href="/search/astro-ph?searchtype=author&query=Rupen%2C+M+P">M. P. Rupen</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">J. L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+M+N">M. N. Williams</a>, <a href="/search/astro-ph?searchtype=author&query=Steinberg%2C+E">E. Steinberg</a>, <a href="/search/astro-ph?searchtype=author&query=Vurm%2C+I">I. Vurm</a>, <a href="/search/astro-ph?searchtype=author&query=Metzger%2C+B+D">B. D. Metzger</a>, <a href="/search/astro-ph?searchtype=author&query=Page%2C+K+L">K. L. Page</a>, <a href="/search/astro-ph?searchtype=author&query=Orio%2C+M">M. Orio</a>, <a href="/search/astro-ph?searchtype=author&query=Quimby%2C+R+M">R. M. Quimby</a>, <a href="/search/astro-ph?searchtype=author&query=Shafter%2C+A+W">A. W. Shafter</a>, <a href="/search/astro-ph?searchtype=author&query=Corbett%2C+H">H. Corbett</a>, <a href="/search/astro-ph?searchtype=author&query=Bolzoni%2C+S">S. Bolzoni</a>, <a href="/search/astro-ph?searchtype=author&query=DeYoung%2C+J">J. DeYoung</a> , et al. (19 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="2302.03043v2-abstract-short" style="display: inline;"> Classical novae are shock-powered multi-wavelength transients triggered by a thermonuclear runaway on an accreting white dwarf. V1674 Her is the fastest nova ever recorded (time to declined by two magnitudes is t_2=1.1 d) that challenges our understanding of shock formation in novae. We investigate the physical mechanisms behind nova emission from GeV gamma-rays to cm-band radio using coordinated… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.03043v2-abstract-full').style.display = 'inline'; document.getElementById('2302.03043v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.03043v2-abstract-full" style="display: none;"> Classical novae are shock-powered multi-wavelength transients triggered by a thermonuclear runaway on an accreting white dwarf. V1674 Her is the fastest nova ever recorded (time to declined by two magnitudes is t_2=1.1 d) that challenges our understanding of shock formation in novae. We investigate the physical mechanisms behind nova emission from GeV gamma-rays to cm-band radio using coordinated Fermi-LAT, NuSTAR, Swift and VLA observations supported by optical photometry. Fermi-LAT detected short-lived (18 h) 0.1-100 GeV emission from V1674 Her that appeared 6 h after the eruption began; this was at a level of (1.6 +/- 0.4)x10^-6 photons cm^-2 s^-1. Eleven days later, simultaneous NuSTAR and Swift X-ray observations revealed optically thin thermal plasma shock-heated to kT_shock = 4 keV. The lack of a detectable 6.7 keV Fe K_alpha emission suggests super-solar CNO abundances. The radio emission from V1674 Her was consistent with thermal emission at early times and synchrotron at late times. The radio spectrum steeply rising with frequency may be a result of either free-free absorption of synchrotron and thermal emission by unshocked outer regions of the nova shell or the Razin-Tsytovich effect attenuating synchrotron emission in dense plasma. The development of the shock inside the ejecta is unaffected by the extraordinarily rapid evolution and the intermediate polar host of this nova. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.03043v2-abstract-full').style.display = 'none'; document.getElementById('2302.03043v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 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">20 pages, 9 figures, 3 tables. Accepted to MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.13193">arXiv:2211.13193</a> <span> [<a href="https://arxiv.org/pdf/2211.13193">pdf</a>, <a href="https://arxiv.org/format/2211.13193">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202244967">10.1051/0004-6361/202244967 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Taking a break: paused accretion in the symbiotic binary RT Cru </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pujol%2C+A">A. Pujol</a>, <a href="/search/astro-ph?searchtype=author&query=Luna%2C+G+J+M">G. J. M. Luna</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">J. L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Kuin%2C+N+P+M">N. P. M. Kuin</a>, <a href="/search/astro-ph?searchtype=author&query=Walter%2C+F+M">F. M. Walter</a>, <a href="/search/astro-ph?searchtype=author&query=Angeloni%2C+R">R. Angeloni</a>, <a href="/search/astro-ph?searchtype=author&query=Nikolov%2C+Y">Y. Nikolov</a>, <a href="/search/astro-ph?searchtype=author&query=de+Oliveira%2C+R+L">R. Lopes de Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=Nu%C3%B1ez%2C+N+E">N. E. Nu帽ez</a>, <a href="/search/astro-ph?searchtype=author&query=Arancibia%2C+M+J">M. Jaque Arancibia</a>, <a href="/search/astro-ph?searchtype=author&query=Palma%2C+T">T. Palma</a>, <a href="/search/astro-ph?searchtype=author&query=Gramajo%2C+L">L. Gramajo</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="2211.13193v1-abstract-short" style="display: inline;"> Symbiotic binaries sometimes hide their symbiotic nature for significant periods of time. There is mounting observational evidence that in those symbiotics that are powered solely by accretion of red-giant's wind material onto a white dwarf, without any quasi-steady shell burning on the surface of the white dwarf, the characteristic emission lines in the optical spectrum can vanish, leaving the se… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.13193v1-abstract-full').style.display = 'inline'; document.getElementById('2211.13193v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.13193v1-abstract-full" style="display: none;"> Symbiotic binaries sometimes hide their symbiotic nature for significant periods of time. There is mounting observational evidence that in those symbiotics that are powered solely by accretion of red-giant's wind material onto a white dwarf, without any quasi-steady shell burning on the surface of the white dwarf, the characteristic emission lines in the optical spectrum can vanish, leaving the semblance of an isolated red giant spectrum. Here we present compelling evidence that this disappearance of optical emission lines from the spectrum of RT Cru during 2019 was due to a decrease in the accretion rate, which we derive by modeling the X-ray spectrum. This drop in accretion rate leads to a lower flux of ionizing photons and thus to faint/absent photoionization emission lines in the optical spectrum. We observed the white dwarf symbiotic RT Cru with XMM-Newton and Swift in X-rays and UV and collected ground-based optical spectra and photometry over the last 33 years. This long-term coverage shows that during most of the year 2019, the accretion rate onto the white dwarf was so low, $\dot{M}= (3.2\pm 0.06)\, \times$10$^{-11}$ $M_{\odot}$ yr$^{-1}$ (d/2.52 kpc)$^2$, that the historically detected hard X-ray emission almost vanished, the UV flux faded by roughly 5 magnitudes, the $U$, $B$ and $V$ flickering amplitude decreased, and the Balmer lines virtually disappeared from January through March 2019. Long-lasting low-accretion episodes as the one reported here may hamper the chances of RT Cru experiencing nova-type outburst despite the high-mass of the accreting white dwarf. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.13193v1-abstract-full').style.display = 'none'; document.getElementById('2211.13193v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 670, A32 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.01232">arXiv:2211.01232</a> <span> [<a href="https://arxiv.org/pdf/2211.01232">pdf</a>, <a href="https://arxiv.org/format/2211.01232">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/acf765">10.3847/1538-4357/acf765 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Luminosity Phase Space of Galactic and Extragalactic X-ray Transients Out to Intermediate Redshifts </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Polzin%2C+A">Ava Polzin</a>, <a href="/search/astro-ph?searchtype=author&query=Margutti%2C+R">Raffaella Margutti</a>, <a href="/search/astro-ph?searchtype=author&query=Coppejans%2C+D">Deanne Coppejans</a>, <a href="/search/astro-ph?searchtype=author&query=Auchettl%2C+K">Katie Auchettl</a>, <a href="/search/astro-ph?searchtype=author&query=Page%2C+K+L">Kim L. Page</a>, <a href="/search/astro-ph?searchtype=author&query=Vasilopoulos%2C+G">Georgios Vasilopoulos</a>, <a href="/search/astro-ph?searchtype=author&query=Bright%2C+J+S">Joe S. Bright</a>, <a href="/search/astro-ph?searchtype=author&query=Esposito%2C+P">Paolo Esposito</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+P+K+G">Peter K. G. Williams</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+E">Edo Berger</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="2211.01232v2-abstract-short" style="display: inline;"> We present a detailed compilation and analysis of the X-ray phase space of low- to intermediate-redshift ($ 0\le z \le 1$) transients that consolidates observed light curves (and theory where necessary) for a large variety of classes of transient/variable phenomena in the 0.3--10 keV energy band. We include gamma-ray burst afterglows, supernovae, supernova shock breakouts and shocks interacting wi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.01232v2-abstract-full').style.display = 'inline'; document.getElementById('2211.01232v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.01232v2-abstract-full" style="display: none;"> We present a detailed compilation and analysis of the X-ray phase space of low- to intermediate-redshift ($ 0\le z \le 1$) transients that consolidates observed light curves (and theory where necessary) for a large variety of classes of transient/variable phenomena in the 0.3--10 keV energy band. We include gamma-ray burst afterglows, supernovae, supernova shock breakouts and shocks interacting with the environment, tidal disruption events and active galactic nuclei, fast blue optical transients, cataclysmic variables, magnetar flares/outbursts and fast radio bursts, cool stellar flares, X-ray binary outbursts, and ultraluminous X-ray sources. Our overarching goal is to offer a comprehensive resource for the examination of these ephemeral events, extending the X-ray duration-luminosity phase space (DLPS) to show luminosity evolution. We use existing observations (both targeted and serendipitous) to characterize the behavior of various transient/variable populations. Contextualizing transient signals in the larger DLPS serves two primary purposes: to identify areas of interest (i.e., regions in the parameter space where one would expect detections, but in which observations have historically been lacking) and to provide initial qualitative guidance in classifying newly discovered transient signals. We find that while the most luminous (largely extragalactic) and least luminous (largely Galactic) part of the phase space is well-populated at $t > 0.1$ days, intermediate luminosity phenomena (L$_x = 10^{34} - 10^{42}$ erg s$^{-1}$) represent a gap in the phase space. We thus identify L$_x = 10^{34} - 10^{42}$ erg s$^{-1}$ and $t = 10^{-4} - 0.1$ days as a key discovery phase space in transient X-ray astronomy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.01232v2-abstract-full').style.display = 'none'; document.getElementById('2211.01232v2-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 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 figures, 13 tables; version accepted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.14132">arXiv:2206.14132</a> <span> [<a href="https://arxiv.org/pdf/2206.14132">pdf</a>, <a href="https://arxiv.org/format/2206.14132">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac8d5e">10.3847/1538-4357/ac8d5e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Galactic Nova Rate: Estimates from the ASAS-SN and Gaia Surveys </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">A. Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">L. Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">J. Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">K. V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">E. Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Kochanek%2C+C+S">C. S. Kochanek</a>, <a href="/search/astro-ph?searchtype=author&query=Stanek%2C+K+Z">K. Z. Stanek</a>, <a href="/search/astro-ph?searchtype=author&query=Kostrzewa-Rutkowska%2C+Z">Z. Kostrzewa-Rutkowska</a>, <a href="/search/astro-ph?searchtype=author&query=Hodgkin%2C+S+T">S. T. Hodgkin</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Shappee%2C+B">B. Shappee</a>, <a href="/search/astro-ph?searchtype=author&query=Jayasinghe%2C+T">T. Jayasinghe</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+M+R">M. Rizzo Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Holoien%2C+T+W+-">T. W. -S. Holoien</a>, <a href="/search/astro-ph?searchtype=author&query=Prieto%2C+J+L">J. L. Prieto</a>, <a href="/search/astro-ph?searchtype=author&query=Thompson%2C+T+A">T. A. Thompson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2206.14132v1-abstract-short" style="display: inline;"> We present the first estimate of the Galactic nova rate based on optical transient surveys covering the entire sky. Using data from the All-Sky Automated Survey for Supernovae (ASAS-SN) and \textit{Gaia} -- the only two all-sky surveys to report classical nova candidates -- we find 39 confirmed Galactic novae and 7 additional unconfirmed candidates discovered from 2019--2021, yielding a nova disco… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.14132v1-abstract-full').style.display = 'inline'; document.getElementById('2206.14132v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.14132v1-abstract-full" style="display: none;"> We present the first estimate of the Galactic nova rate based on optical transient surveys covering the entire sky. Using data from the All-Sky Automated Survey for Supernovae (ASAS-SN) and \textit{Gaia} -- the only two all-sky surveys to report classical nova candidates -- we find 39 confirmed Galactic novae and 7 additional unconfirmed candidates discovered from 2019--2021, yielding a nova discovery rate of $\approx 14$ yr$^{-1}$. Using accurate Galactic stellar mass models, three-dimensional dust maps, and incorporating realistic nova light curves, we have built a sophisticated Galactic nova model that allows an estimate of the recovery fraction of Galactic novae from these surveys over this time period. The observing capabilities of each survey are distinct: the high cadence of ASAS-SN makes it sensitive to fast novae, while the broad observing filter and high spatial resolution of \textit{Gaia} make it more sensitive to highly reddened novae across the entire Galactic plane and bulge. Despite these differences, we find that ASAS-SN and \textit{Gaia} give consistent Galactic nova rates, with a final joint nova rate of $26 \pm 5$ yr$^{-1}$. This inferred nova rate is substantially lower than found by many other recent studies. Critically assessing the systematic uncertainties in the Galactic nova rate, we argue that the role of faint fast-fading novae has likely been overestimated, but that subtle details in the operation of transient alert pipelines can have large, sometimes unappreciated effects on transient recovery efficiency. Our predicted nova rate can be directly tested with forthcoming red/near-infrared transient surveys in the southern hemisphere. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.14132v1-abstract-full').style.display = 'none'; document.getElementById('2206.14132v1-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 9 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/2206.10625">arXiv:2206.10625</a> <span> [<a href="https://arxiv.org/pdf/2206.10625">pdf</a>, <a href="https://arxiv.org/ps/2206.10625">ps</a>, <a href="https://arxiv.org/format/2206.10625">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac7b25">10.3847/1538-4357/ac7b25 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> 1RXH J082623.6-505741: a new long-period cataclysmic variable with an evolved donor and a low mass transfer rate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">Kirill V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">Jay Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Swihart%2C+S+J">Samuel J. Swihart</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">Elias Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Bahramian%2C+A">Arash Bahramian</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Heinke%2C+C+O">Craig O. Heinke</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+A+K">Allison K. Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+K">Kwan-Lok Li</a>, <a href="/search/astro-ph?searchtype=author&query=de+Oliveira%2C+R+L">Raimundo Lopes de Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=Miller-Jones%2C+J+C+A">James C. A. Miller-Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Sand%2C+D+J">David J. Sand</a>, <a href="/search/astro-ph?searchtype=author&query=Shishkovsky%2C+L">Laura Shishkovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Tremou%2C+E">Evangelia Tremou</a>, <a href="/search/astro-ph?searchtype=author&query=Voggel%2C+K">Karina Voggel</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2206.10625v1-abstract-short" style="display: inline;"> We report the discovery of 1RXH J082623.6-505741, a 10.4 hr orbital period compact binary. Modeling extensive optical photometry and spectroscopy reveals a $\sim 0.4 M_{\odot}$ K-type secondary transferring mass through a low-state accretion disk to a non-magnetic $\sim 0.8 M_{\odot}$ white dwarf. The secondary is overluminous for its mass and dominates the optical spectra at all epochs, and must… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.10625v1-abstract-full').style.display = 'inline'; document.getElementById('2206.10625v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.10625v1-abstract-full" style="display: none;"> We report the discovery of 1RXH J082623.6-505741, a 10.4 hr orbital period compact binary. Modeling extensive optical photometry and spectroscopy reveals a $\sim 0.4 M_{\odot}$ K-type secondary transferring mass through a low-state accretion disk to a non-magnetic $\sim 0.8 M_{\odot}$ white dwarf. The secondary is overluminous for its mass and dominates the optical spectra at all epochs, and must be evolved to fill its Roche Lobe at this orbital period. The X-ray luminosity $L_X \sim 1$-$2 \times 10^{32}$ erg s$^{-1}$ derived from both new XMM-Newton and archival observations, although high compared to most CVs, still only requires a modest accretion rate onto the white dwarf of $\dot{M} \sim 3 \times 10^{-11}$ to $3 \times 10^{-10} M_{\odot}$ yr$^{-1}$, lower than expected for a cataclysmic variable with an evolved secondary. No dwarf nova outbursts have yet been observed from the system, consistent with the low derived mass transfer rate. Several other cataclysmic variables with similar orbital periods also show unexpectedly low mass transfer rates, even though selection effects disfavor the discovery of binaries with these properties. This suggests the abundance and evolutionary state of long-period, low mass transfer rate cataclysmic variables is worthy of additional attention. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.10625v1-abstract-full').style.display = 'none'; document.getElementById('2206.10625v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 8 figures, 1 table, accepted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.08365">arXiv:2202.08365</a> <span> [<a href="https://arxiv.org/pdf/2202.08365">pdf</a>, <a href="https://arxiv.org/format/2202.08365">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac5682">10.3847/1538-4357/ac5682 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigating the low-flux states in six Intermediate Polars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Covington%2C+A+E">Ava E. Covington</a>, <a href="/search/astro-ph?searchtype=author&query=Shaw%2C+A+W">Aarran W. Shaw</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Littlefield%2C+C">Colin Littlefield</a>, <a href="/search/astro-ph?searchtype=author&query=Heinke%2C+C+O">Craig O. Heinke</a>, <a href="/search/astro-ph?searchtype=author&query=Plotkin%2C+R+M">Richard M. Plotkin</a>, <a href="/search/astro-ph?searchtype=author&query=Barrett%2C+D">Doug Barrett</a>, <a href="/search/astro-ph?searchtype=author&query=Boardman%2C+J">James Boardman</a>, <a href="/search/astro-ph?searchtype=author&query=Boyd%2C+D">David Boyd</a>, <a href="/search/astro-ph?searchtype=author&query=Brincat%2C+S+M">Stephen M. Brincat</a>, <a href="/search/astro-ph?searchtype=author&query=Carstens%2C+R">Rolf Carstens</a>, <a href="/search/astro-ph?searchtype=author&query=Collins%2C+D+F">Donald F. Collins</a>, <a href="/search/astro-ph?searchtype=author&query=Cook%2C+L+M">Lewis M. Cook</a>, <a href="/search/astro-ph?searchtype=author&query=Cooney%2C+W+R">Walter R. Cooney</a>, <a href="/search/astro-ph?searchtype=author&query=Fern%C3%A1ndez%2C+D+C">David Cejudo Fern谩ndez</a>, <a href="/search/astro-ph?searchtype=author&query=Dufoer%2C+S">Sjoerd Dufoer</a>, <a href="/search/astro-ph?searchtype=author&query=Dvorak%2C+S">Shawn Dvorak</a>, <a href="/search/astro-ph?searchtype=author&query=Galdies%2C+C">Charles Galdies</a>, <a href="/search/astro-ph?searchtype=author&query=Goff%2C+W">William Goff</a>, <a href="/search/astro-ph?searchtype=author&query=Hambsch%2C+F">Franz-Josef Hambsch</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+S">Steve Johnston</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+J">Jim Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Menzies%2C+K">Kenneth Menzies</a>, <a href="/search/astro-ph?searchtype=author&query=Monard%2C+L+A+G">Libert A. G. Monard</a>, <a href="/search/astro-ph?searchtype=author&query=Morelle%2C+E">Etienne Morelle</a> , et al. (8 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2202.08365v2-abstract-short" style="display: inline;"> We present optical photometry of six intermediate polars that exhibit transitions to a low-flux state. For four of these systems, DW Cnc, V515 And, V1223 Sgr and RX J2133.7+5107, we are able to perform timing analysis in and out of the low states. We find that, for DW Cnc and V515 And, the dominant periodicities in the light curves change as the flux decreases, indicating a change in the sources'… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.08365v2-abstract-full').style.display = 'inline'; document.getElementById('2202.08365v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.08365v2-abstract-full" style="display: none;"> We present optical photometry of six intermediate polars that exhibit transitions to a low-flux state. For four of these systems, DW Cnc, V515 And, V1223 Sgr and RX J2133.7+5107, we are able to perform timing analysis in and out of the low states. We find that, for DW Cnc and V515 And, the dominant periodicities in the light curves change as the flux decreases, indicating a change in the sources' accretion properties as they transition to the low state. For V1223 Sgr we find that the variability is almost completely quenched at the lowest flux, but do not find evidence for a changing accretion geometry. For RX J2133.7+5107, the temporal properties do not change in the low state, but we do see a period of enhanced accretion that is coincident with increased variability on the beat frequency, which we do not associate with a change in the accretion mechanisms in the system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.08365v2-abstract-full').style.display = 'none'; document.getElementById('2202.08365v2-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 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 10 figures, accepted for publication in ApJ. The authors recommend downloading the PDF of this paper, as it takes a while to render online</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.11170">arXiv:2201.11170</a> <span> [<a href="https://arxiv.org/pdf/2201.11170">pdf</a>, <a href="https://arxiv.org/format/2201.11170">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/stac263">10.1093/mnras/stac263 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Classifying IGR J18007-4146 as an intermediate polar using XMM and NuSTAR </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Coughenour%2C+B+M">Benjamin M. Coughenour</a>, <a href="/search/astro-ph?searchtype=author&query=Tomsick%2C+J+A">John A. Tomsick</a>, <a href="/search/astro-ph?searchtype=author&query=Shaw%2C+A+W">Aarran W. Shaw</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Clavel%2C+M">Ma茂ca Clavel</a>, <a href="/search/astro-ph?searchtype=author&query=Hare%2C+J">Jeremy Hare</a>, <a href="/search/astro-ph?searchtype=author&query=Krivonos%2C+R">Roman Krivonos</a>, <a href="/search/astro-ph?searchtype=author&query=Fornasini%2C+F+M">Francesca M. Fornasini</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="2201.11170v1-abstract-short" style="display: inline;"> Many new and unidentified Galactic sources have recently been revealed by ongoing hard X-ray surveys. A significant fraction of these have been shown to be the type of accreting white dwarfs known as cataclysmic variables (CVs). Follow-up observations are often required to categorize and classify these sources, and may also identify potentially unique or interesting cases. One such case is IGR J18… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.11170v1-abstract-full').style.display = 'inline'; document.getElementById('2201.11170v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.11170v1-abstract-full" style="display: none;"> Many new and unidentified Galactic sources have recently been revealed by ongoing hard X-ray surveys. A significant fraction of these have been shown to be the type of accreting white dwarfs known as cataclysmic variables (CVs). Follow-up observations are often required to categorize and classify these sources, and may also identify potentially unique or interesting cases. One such case is IGR J18007-4146, which is likely a CV based on follow-up Chandra observations and constraints from optical/IR catalogs. Utilizing simultaneous XMM-Newton and NuSTAR observations, as well as the available optical/IR data, we confirm the nature of IGR J18007-4146 as an intermediate polar type CV. Timing analysis of the XMM data reveals a periodic signal at 424.4 +/- 0.7 s that we interpret as the spin period of the white dwarf. Modeling the 0.3-78 keV spectrum, we use a thermal bremsstrahlung continuum but require intrinsic absorption as well as a soft component and strong Fe lines between 6 and 7 keV. We model the soft component using a single-temperature blackbody with kT = 73 +8/-6 eV. From the X-ray spectrum, we are able to measure the mass of the white dwarf to be 1.06 +0.19/-0.10 Msun, which means IGR J18007-4146 is more massive than the average for magnetic CVs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.11170v1-abstract-full').style.display = 'none'; document.getElementById('2201.11170v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 January, 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">9 pages, 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/2201.07313">arXiv:2201.07313</a> <span> [<a href="https://arxiv.org/pdf/2201.07313">pdf</a>, <a href="https://arxiv.org/format/2201.07313">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/ac6def">10.3847/1538-4357/ac6def <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for Spatial Correlations of Neutrinos with Ultra-High-Energy Cosmic Rays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+ANTARES+collaboration"> The ANTARES collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+A">A. Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Alves%2C+S">S. Alves</a>, <a href="/search/astro-ph?searchtype=author&query=Andr%C3%A9%2C+M">M. Andr茅</a>, <a href="/search/astro-ph?searchtype=author&query=Anghinolfi%2C+M">M. Anghinolfi</a>, <a href="/search/astro-ph?searchtype=author&query=Ardid%2C+M">M. Ardid</a>, <a href="/search/astro-ph?searchtype=author&query=Ardid%2C+S">S. Ardid</a>, <a href="/search/astro-ph?searchtype=author&query=Aubert%2C+J+-">J. -J. Aubert</a>, <a href="/search/astro-ph?searchtype=author&query=Aublin%2C+J">J. Aublin</a>, <a href="/search/astro-ph?searchtype=author&query=Baret%2C+B">B. Baret</a>, <a href="/search/astro-ph?searchtype=author&query=Basa%2C+S">S. Basa</a>, <a href="/search/astro-ph?searchtype=author&query=Belhorma%2C+B">B. Belhorma</a>, <a href="/search/astro-ph?searchtype=author&query=Bendahman%2C+M">M. Bendahman</a>, <a href="/search/astro-ph?searchtype=author&query=Bertin%2C+V">V. Bertin</a>, <a href="/search/astro-ph?searchtype=author&query=Biagi%2C+S">S. Biagi</a>, <a href="/search/astro-ph?searchtype=author&query=Bissinger%2C+M">M. Bissinger</a>, <a href="/search/astro-ph?searchtype=author&query=Boumaaza%2C+J">J. Boumaaza</a>, <a href="/search/astro-ph?searchtype=author&query=Bouta%2C+M">M. Bouta</a>, <a href="/search/astro-ph?searchtype=author&query=Bouwhuis%2C+M+C">M. C. Bouwhuis</a>, <a href="/search/astro-ph?searchtype=author&query=Br%C3%A2nza%C5%9F%2C+H">H. Br芒nza艧</a>, <a href="/search/astro-ph?searchtype=author&query=Bruijn%2C+R">R. Bruijn</a>, <a href="/search/astro-ph?searchtype=author&query=Brunner%2C+J">J. Brunner</a>, <a href="/search/astro-ph?searchtype=author&query=Busto%2C+J">J. Busto</a>, <a href="/search/astro-ph?searchtype=author&query=Caiffi%2C+B">B. Caiffi</a>, <a href="/search/astro-ph?searchtype=author&query=Calvo%2C+D">D. Calvo</a> , et al. (1025 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2201.07313v3-abstract-short" style="display: inline;"> For several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of high-energy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for corre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.07313v3-abstract-full').style.display = 'inline'; document.getElementById('2201.07313v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.07313v3-abstract-full" style="display: none;"> For several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of high-energy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for correlating the arrival directions of neutrinos with the arrival directions of UHECRs. The neutrino data is provided by the IceCube Neutrino Observatory and ANTARES, while the UHECR data with energies above $\sim$50 EeV is provided by the Pierre Auger Observatory and the Telescope Array. All experiments provide increased statistics and improved reconstructions with respect to our previous results reported in 2015. The first analysis uses a high-statistics neutrino sample optimized for point-source searches to search for excesses of neutrinos clustering in the vicinity of UHECR directions. The second analysis searches for an excess of UHECRs in the direction of the highest-energy neutrinos. The third analysis searches for an excess of pairs of UHECRs and highest-energy neutrinos on different angular scales. None of the analyses has found a significant excess, and previously reported over-fluctuations are reduced in significance. Based on these results, we further constrain the neutrino flux spatially correlated with UHECRs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.07313v3-abstract-full').style.display = 'none'; document.getElementById('2201.07313v3-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 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">39 pages, 7 figures, 4 tables; updated source files including xml authorlist</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> FERMILAB-PUB-22-033-AD-PPD-SCD-TD </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 934 164 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.09962">arXiv:2111.09962</a> <span> [<a href="https://arxiv.org/pdf/2111.09962">pdf</a>, <a href="https://arxiv.org/format/2111.09962">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevD.105.062002">10.1103/PhysRevD.105.062002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of Variations in Cosmic Ray Single Count Rates During Thunderstorms and Implications for Large-Scale Electric Field Changes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abbasi%2C+R+U">R. U. Abbasi</a>, <a href="/search/astro-ph?searchtype=author&query=Abu-Zayyad%2C+T">T. Abu-Zayyad</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+M">M. Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Arai%2C+Y">Y. Arai</a>, <a href="/search/astro-ph?searchtype=author&query=Arimura%2C+R">R. Arimura</a>, <a href="/search/astro-ph?searchtype=author&query=Barcikowski%2C+E">E. Barcikowski</a>, <a href="/search/astro-ph?searchtype=author&query=Belz%2C+J+W">J. W. Belz</a>, <a href="/search/astro-ph?searchtype=author&query=Bergman%2C+D+R">D. R. Bergman</a>, <a href="/search/astro-ph?searchtype=author&query=Blake%2C+S+A">S. A. Blake</a>, <a href="/search/astro-ph?searchtype=author&query=Buckland%2C+I">I. Buckland</a>, <a href="/search/astro-ph?searchtype=author&query=Cady%2C+R">R. Cady</a>, <a href="/search/astro-ph?searchtype=author&query=Cheon%2C+B+G">B. G. Cheon</a>, <a href="/search/astro-ph?searchtype=author&query=Chiba%2C+J">J. Chiba</a>, <a href="/search/astro-ph?searchtype=author&query=Chikawa%2C+M">M. Chikawa</a>, <a href="/search/astro-ph?searchtype=author&query=Fujii%2C+T">T. Fujii</a>, <a href="/search/astro-ph?searchtype=author&query=Fujisue%2C+K">K. Fujisue</a>, <a href="/search/astro-ph?searchtype=author&query=Fujita%2C+K">K. Fujita</a>, <a href="/search/astro-ph?searchtype=author&query=Fujiwara%2C+R">R. Fujiwara</a>, <a href="/search/astro-ph?searchtype=author&query=Fukushima%2C+M">M. Fukushima</a>, <a href="/search/astro-ph?searchtype=author&query=Fukushima%2C+R">R. Fukushima</a>, <a href="/search/astro-ph?searchtype=author&query=Furlich%2C+G">G. Furlich</a>, <a href="/search/astro-ph?searchtype=author&query=Globus%2C+N">N. Globus</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+R">R. Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Hanlon%2C+W">W. Hanlon</a>, <a href="/search/astro-ph?searchtype=author&query=Hayashi%2C+M">M. Hayashi</a> , et al. (140 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2111.09962v1-abstract-short" style="display: inline;"> We present the first observation by the Telescope Array Surface Detector (TASD) of the effect of thunderstorms on the development of cosmic ray single count rate intensity over a 700 km$^{2}$ area. Observations of variations in the secondary low-energy cosmic ray counting rate, using the TASD, allow us to study the electric field inside thunderstorms, on a large scale, as it progresses on top of t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.09962v1-abstract-full').style.display = 'inline'; document.getElementById('2111.09962v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.09962v1-abstract-full" style="display: none;"> We present the first observation by the Telescope Array Surface Detector (TASD) of the effect of thunderstorms on the development of cosmic ray single count rate intensity over a 700 km$^{2}$ area. Observations of variations in the secondary low-energy cosmic ray counting rate, using the TASD, allow us to study the electric field inside thunderstorms, on a large scale, as it progresses on top of the 700 km$^{2}$ detector, without dealing with the limitation of narrow exposure in time and space using balloons and aircraft detectors. In this work, variations in the cosmic ray intensity (single count rate) using the TASD, were studied and found to be on average at the $\sim(0.5-1)\%$ and up to 2\% level. These observations were found to be both in excess and in deficit. They were also found to be correlated with lightning in addition to thunderstorms. These variations lasted for tens of minutes; their footprint on the ground ranged from 6 to 24 km in diameter and moved in the same direction as the thunderstorm. With the use of simple electric field models inside the cloud and between cloud to ground, the observed variations in the cosmic ray single count rate were recreated using CORSIKA simulations. Depending on the electric field model used and the direction of the electric field in that model, the electric field magnitude that reproduces the observed low-energy cosmic ray single count rate variations was found to be approximately between 0.2-0.4 GV. This in turn allows us to get a reasonable insight on the electric field and its effect on cosmic ray air showers inside thunderstorms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.09962v1-abstract-full').style.display = 'none'; document.getElementById('2111.09962v1-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 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.14827">arXiv:2110.14827</a> <span> [<a href="https://arxiv.org/pdf/2110.14827">pdf</a>, <a href="https://arxiv.org/format/2110.14827">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"> Indications of a Cosmic Ray Source in the Perseus-Pisces Supercluster </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Telescope+Array+Collaboration"> Telescope Array Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Abbasi%2C+R+U">R. U. Abbasi</a>, <a href="/search/astro-ph?searchtype=author&query=Abu-Zayyad%2C+T">T. Abu-Zayyad</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+M">M. Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Arai%2C+Y">Y. Arai</a>, <a href="/search/astro-ph?searchtype=author&query=Arimura%2C+R">R. Arimura</a>, <a href="/search/astro-ph?searchtype=author&query=Barcikowski%2C+E">E. Barcikowski</a>, <a href="/search/astro-ph?searchtype=author&query=Belz%2C+J+W">J. W. Belz</a>, <a href="/search/astro-ph?searchtype=author&query=Bergman%2C+D+R">D. R. Bergman</a>, <a href="/search/astro-ph?searchtype=author&query=Blake%2C+S+A">S. A. Blake</a>, <a href="/search/astro-ph?searchtype=author&query=Buckland%2C+I">I. Buckland</a>, <a href="/search/astro-ph?searchtype=author&query=Cady%2C+R">R. Cady</a>, <a href="/search/astro-ph?searchtype=author&query=Cheon%2C+B+G">B. G. Cheon</a>, <a href="/search/astro-ph?searchtype=author&query=Chiba%2C+J">J. Chiba</a>, <a href="/search/astro-ph?searchtype=author&query=Chikawa%2C+M">M. Chikawa</a>, <a href="/search/astro-ph?searchtype=author&query=Fujii%2C+T">T. Fujii</a>, <a href="/search/astro-ph?searchtype=author&query=Fujisue%2C+K">K. Fujisue</a>, <a href="/search/astro-ph?searchtype=author&query=Fujita%2C+K">K. Fujita</a>, <a href="/search/astro-ph?searchtype=author&query=Fujiwara%2C+R">R. Fujiwara</a>, <a href="/search/astro-ph?searchtype=author&query=Fukushima%2C+M">M. Fukushima</a>, <a href="/search/astro-ph?searchtype=author&query=Fukushima%2C+R">R. Fukushima</a>, <a href="/search/astro-ph?searchtype=author&query=Furlich%2C+G">G. Furlich</a>, <a href="/search/astro-ph?searchtype=author&query=Globus%2C+N">N. Globus</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+R">R. Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Hanlon%2C+W">W. Hanlon</a> , et al. (135 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="2110.14827v1-abstract-short" style="display: inline;"> The Telescope Array Collaboration has observed an excess of events with $E \ge 10^{19.4} ~{\rm eV}$ in the data which is centered at (RA, dec) = ($19^\circ$, $35^\circ$). This is near the center of the Perseus-Pisces supercluster (PPSC). The PPSC is about $70 ~{\rm Mpc}$ distant and is the closest supercluster in the Northern Hemisphere (other than the Virgo supercluster of which we are a part). A… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.14827v1-abstract-full').style.display = 'inline'; document.getElementById('2110.14827v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.14827v1-abstract-full" style="display: none;"> The Telescope Array Collaboration has observed an excess of events with $E \ge 10^{19.4} ~{\rm eV}$ in the data which is centered at (RA, dec) = ($19^\circ$, $35^\circ$). This is near the center of the Perseus-Pisces supercluster (PPSC). The PPSC is about $70 ~{\rm Mpc}$ distant and is the closest supercluster in the Northern Hemisphere (other than the Virgo supercluster of which we are a part). A Li-Ma oversampling analysis with $20^\circ$-radius circles indicates an excess in the arrival direction of events with a local significance of about 4 standard deviations. The probability of having such excess close to the PPSC by chance is estimated to be 3.5 standard deviations. This result indicates that a cosmic ray source likely exists in that supercluster. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.14827v1-abstract-full').style.display = 'none'; document.getElementById('2110.14827v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.04315">arXiv:2110.04315</a> <span> [<a href="https://arxiv.org/pdf/2110.04315">pdf</a>, <a href="https://arxiv.org/ps/2110.04315">ps</a>, <a href="https://arxiv.org/format/2110.04315">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac4583">10.3847/1538-4357/ac4583 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Expanding Bipolar X-ray Structure After the 2006 Eruption of RS Oph </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Montez%2C+R">R. Montez Jr.</a>, <a href="/search/astro-ph?searchtype=author&query=Luna%2C+G+J+M">G. J. M. Luna</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J">J. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Kastner%2C+J+H">J. H. Kastner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2110.04315v1-abstract-short" style="display: inline;"> We report on the detection and analysis of extended X-ray emission by the {\it Chandra} X-ray Observatory stemming from the 2006 eruption of the recurrent novae RS Oph. The extended emission was detected 1254 and 1927 days after the start of the 2006 eruption and is consistent with a bipolar flow oriented in the east-west direction of the sky with opening angles of approximately $70^{\circ}$. The… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.04315v1-abstract-full').style.display = 'inline'; document.getElementById('2110.04315v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.04315v1-abstract-full" style="display: none;"> We report on the detection and analysis of extended X-ray emission by the {\it Chandra} X-ray Observatory stemming from the 2006 eruption of the recurrent novae RS Oph. The extended emission was detected 1254 and 1927 days after the start of the 2006 eruption and is consistent with a bipolar flow oriented in the east-west direction of the sky with opening angles of approximately $70^{\circ}$. The length of both lobes appeared to expand from 1.3 arcsec in 2009 to 2.0 arcsec in 2011, suggesting a projected expansion rate of $1.1\pm0.1 {\rm ~mas~day}^{-1}$ and an expansion velocity of $4600\ {\rm km~s}^{-1}\ (D/2.4\ {\rm kpc})$ in the plane of the sky. This expansion rate is consistent with previous estimates from optical and radio observations of material in a similar orientation. The X-ray emission does not show any evidence of cooling between 2009 and 2011, consistent with free expansion of the material. This discovery suggests that some mechanism collimates ejecta away from the equatorial plane, and that after that material passes through the red-giant wind, it expands freely into the cavity left by the 1985 eruption. We expect similar structures to arise from latest eruption and to expand into the cavity shaped by the 2006 eruption. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.04315v1-abstract-full').style.display = 'none'; document.getElementById('2110.04315v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 4 figures, submitted to ApJ and as a chapter to my memoir: thank you for your patience, or other ways to stop apologizing for being late</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.07868">arXiv:2108.07868</a> <span> [<a href="https://arxiv.org/pdf/2108.07868">pdf</a>, <a href="https://arxiv.org/format/2108.07868">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> The 2019 outburst of the 2005 classical nova V1047 Cen: a record breaking dwarf nova outburst or a new phenomenon? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">E. Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">K. V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Bright%2C+J+S">J. S. Bright</a>, <a href="/search/astro-ph?searchtype=author&query=Tremou%2C+E">E. Tremou</a>, <a href="/search/astro-ph?searchtype=author&query=Nyamai%2C+M+M">M. M. Nyamai</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+A">A. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">J. Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">L. Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Myers%2C+G">G. Myers</a>, <a href="/search/astro-ph?searchtype=author&query=Hambsch%2C+F">F-J. Hambsch</a>, <a href="/search/astro-ph?searchtype=author&query=Page%2C+K+L">K. L. Page</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D+A+H">D. A. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Woodward%2C+C+E">C. E. Woodward</a>, <a href="/search/astro-ph?searchtype=author&query=Walter%2C+F+M">F. M. Walter</a>, <a href="/search/astro-ph?searchtype=author&query=Mr%C3%B3z%2C+P">P. Mr贸z</a>, <a href="/search/astro-ph?searchtype=author&query=Vallely%2C+P+J">P. J. Vallely</a>, <a href="/search/astro-ph?searchtype=author&query=Geballe%2C+T+R">T. R. Geballe</a>, <a href="/search/astro-ph?searchtype=author&query=Banerjee%2C+D+P+K">D. P. K. Banerjee</a>, <a href="/search/astro-ph?searchtype=author&query=Gehrz%2C+R+D">R. D. Gehrz</a>, <a href="/search/astro-ph?searchtype=author&query=Fender%2C+R+P">R. P. Fender</a>, <a href="/search/astro-ph?searchtype=author&query=Gromadzki%2C+M">M. Gromadzki</a>, <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">A. Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Knigge%2C+C">C. Knigge</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Munari%2C+U">U. Munari</a> , et al. (6 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2108.07868v2-abstract-short" style="display: inline;"> We present a detailed study of the 2019 outburst of the cataclysmic variable V1047~Cen, which hosted a classical nova eruption in 2005. The peculiar outburst occurred 14 years after the classical nova event and lasted for more than 400 days, reaching an amplitude of around 6 magnitudes in the optical. Early spectral follow-up revealed what could be a dwarf nova (accretion disk instability) outburs… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.07868v2-abstract-full').style.display = 'inline'; document.getElementById('2108.07868v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.07868v2-abstract-full" style="display: none;"> We present a detailed study of the 2019 outburst of the cataclysmic variable V1047~Cen, which hosted a classical nova eruption in 2005. The peculiar outburst occurred 14 years after the classical nova event and lasted for more than 400 days, reaching an amplitude of around 6 magnitudes in the optical. Early spectral follow-up revealed what could be a dwarf nova (accretion disk instability) outburst. However, the outburst duration, high velocity ($>$2000\,km\,s$^{-1}$) features in the optical line profiles, luminous optical emission, and presence of prominent long-lasting radio emission together suggest a phenomenon more exotic and energetic than a dwarf nova outburst. The outburst amplitude, radiated energy, and spectral evolution are also not consistent with a classical nova eruption. There are similarities between V1047~Cen's 2019 outburst and those of classical symbiotic stars, but pre-2005 images of the field of V1047~Cen indicate that the system likely hosts a dwarf companion, implying a typical cataclysmic variable system. Based on our multi-wavelength observations, we suggest that the outburst may have started with a brightening of the disk due to enhanced mass transfer or disk instability, possibly leading to enhanced nuclear shell burning on the white dwarf, which was already experiencing some level of quasi-steady shell burning. This eventually led to the generation of a wind and/or bipolar, collimated outflows. The 2019 outburst of V1047~Cen appears to be unique, and nothing similar has been observed in a typical cataclysmic variable system before, hinting at a potentially new astrophysical phenomenon. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.07868v2-abstract-full').style.display = 'none'; document.getElementById('2108.07868v2-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 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">36 pages, 24 figures, 9 tables. Accepted 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/2108.03241">arXiv:2108.03241</a> <span> [<a href="https://arxiv.org/pdf/2108.03241">pdf</a>, <a href="https://arxiv.org/ps/2108.03241">ps</a>, <a href="https://arxiv.org/format/2108.03241">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stac1440">10.1093/mnras/stac1440 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The first nova eruption in a novalike variable: YZ Ret as seen in X-rays and gamma-rays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">Kirill V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+K">Kwan-Lok Li</a>, <a href="/search/astro-ph?searchtype=author&query=de+Oliveira%2C+R+L">Raimundo Lopes de Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=Ness%2C+J">Jan-Uwe Ness</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">Elias Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Steinberg%2C+E">Elad Steinberg</a>, <a href="/search/astro-ph?searchtype=author&query=Vurm%2C+I">Indrek Vurm</a>, <a href="/search/astro-ph?searchtype=author&query=Metzger%2C+B+D">Brian D. Metzger</a>, <a href="/search/astro-ph?searchtype=author&query=Babul%2C+A">Aliya-Nur Babul</a>, <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">Adam Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">Justin D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=Nelson%2C+T">Thomas Nelson</a>, <a href="/search/astro-ph?searchtype=author&query=Page%2C+K+L">Kim L. Page</a>, <a href="/search/astro-ph?searchtype=author&query=Rupen%2C+M+P">Michael P. Rupen</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">Jennifer L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">Jay Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Kilkenny%2C+D">David Kilkenny</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="2108.03241v2-abstract-short" style="display: inline;"> Peaking at 3.7 mag on 2020 July 11, YZ Ret was the second-brightest nova of the decade. The nova's moderate proximity (2.7 kpc from Gaia) provided an opportunity to explore its multi-wavelength properties in great detail. Here we report on YZ Ret as part of a long-term project to identify the physical mechanisms responsible for high-energy emission in classical novae. We use simultaneous Fermi/LAT… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.03241v2-abstract-full').style.display = 'inline'; document.getElementById('2108.03241v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.03241v2-abstract-full" style="display: none;"> Peaking at 3.7 mag on 2020 July 11, YZ Ret was the second-brightest nova of the decade. The nova's moderate proximity (2.7 kpc from Gaia) provided an opportunity to explore its multi-wavelength properties in great detail. Here we report on YZ Ret as part of a long-term project to identify the physical mechanisms responsible for high-energy emission in classical novae. We use simultaneous Fermi/LAT and NuSTAR observations complemented by XMM-Newton X-ray grating spectroscopy to probe the physical parameters of the shocked ejecta and the nova-hosting white dwarf. The XMM-Newton observations revealed a super-soft X-ray emission which is dominated by emission lines of CV, CVI, NVI, NVII, and OVIII rather than a blackbody-like continuum, suggesting CO-composition of the white dwarf in a high-inclination binary system. Fermi/LAT detected YZ Ret for 15 days with the gamma-ray spectrum best described by a power law with an exponential cut-off at 1.9 +/-0.6 GeV. In stark contrast with theoretical predictions and in keeping with previous NuSTAR observations of Fermi-detected classical novae (V5855 Sgr and V906 Car), the 3.5-78 keV X-ray emission is found to be two orders of magnitude fainter than the GeV emission. The X-ray emission observed by NuSTAR is consistent with a single-temperature thermal plasma. We detect no non-thermal tail of the GeV emission expected to extend down to the NuSTAR band. NuSTAR observations continue to challenge theories of high-energy emission from shocks in novae. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.03241v2-abstract-full').style.display = 'none'; document.getElementById('2108.03241v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages, 5 figures, 4 tables; accepted to MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.06251">arXiv:2107.06251</a> <span> [<a href="https://arxiv.org/pdf/2107.06251">pdf</a>, <a href="https://arxiv.org/format/2107.06251">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4365/ac24ab">10.3847/1538-4365/ac24ab <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Classical Novae at Radio Wavelengths </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">Justin D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">Elias Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Bannister%2C+K+W">Keith W. Bannister</a>, <a href="/search/astro-ph?searchtype=author&query=Krauss%2C+M+I">Miriam I. Krauss</a>, <a href="/search/astro-ph?searchtype=author&query=Mioduszewski%2C+A+J">Amy J. Mioduszewski</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Nelson%2C+T+J">Thomas J. Nelson</a>, <a href="/search/astro-ph?searchtype=author&query=Rupen%2C+M+P">Michael P. Rupen</a>, <a href="/search/astro-ph?searchtype=author&query=Ryder%2C+S+D">Stuart D. Ryder</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">Jennifer L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">Kirill V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">Jay Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Filipovic%2C+M+D">Miroslav D. Filipovic</a>, <a href="/search/astro-ph?searchtype=author&query=Finzell%2C+T">Tom Finzell</a>, <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">Adam Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Kool%2C+E+C">Erik C. Kool</a>, <a href="/search/astro-ph?searchtype=author&query=Metzger%2C+B+D">Brian D. Metzger</a>, <a href="/search/astro-ph?searchtype=author&query=Nyamai%2C+M+M">Miriam M. Nyamai</a>, <a href="/search/astro-ph?searchtype=author&query=Ribeiro%2C+V+A+R+M">Valerio A. R. M. Ribeiro</a>, <a href="/search/astro-ph?searchtype=author&query=Roy%2C+N">Nirupam Roy</a>, <a href="/search/astro-ph?searchtype=author&query=Urquhart%2C+R">Ryan Urquhart</a>, <a href="/search/astro-ph?searchtype=author&query=Weston%2C+J">Jennifer Weston</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="2107.06251v1-abstract-short" style="display: inline;"> We present radio observations (1--40 GHz) for 36 classical novae, representing data from over five decades compiled from the literature, telescope archives, and our own programs. Our targets display a striking diversity in their optical parameters (e.g., spanning optical fading timescales, t_2 = 1--263 days), and we find a similar diversity in the radio light curves. Using a brightness temperature… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.06251v1-abstract-full').style.display = 'inline'; document.getElementById('2107.06251v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.06251v1-abstract-full" style="display: none;"> We present radio observations (1--40 GHz) for 36 classical novae, representing data from over five decades compiled from the literature, telescope archives, and our own programs. Our targets display a striking diversity in their optical parameters (e.g., spanning optical fading timescales, t_2 = 1--263 days), and we find a similar diversity in the radio light curves. Using a brightness temperature analysis, we find that radio emission from novae is a mixture of thermal and synchrotron emission, with non-thermal emission observed at earlier times. We identify high brightness temperature emission (T_B > 5x10^4 K) as an indication of synchrotron emission in at least 9 (25%) of the novae. We find a class of synchrotron-dominated novae with mildly evolved companions, exemplified by V5589 Sgr and V392 Per, that appear to be a bridge between classical novae with dwarf companions and symbiotic binaries with giant companions. Four of the novae in our sample have two distinct radio maxima (the first dominated by synchrotron and the later by thermal emission), and in four cases the early synchrotron peak is temporally coincident with a dramatic dip in the optical light curve, hinting at a common site for particle acceleration and dust formation. We publish the light curves as tables and encourage use of these data by the broader community in multi-wavelength studies and modeling efforts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.06251v1-abstract-full').style.display = 'none'; document.getElementById('2107.06251v1-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 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">Submitted to AAS Journals</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/2106.01611">arXiv:2106.01611</a> <span> [<a href="https://arxiv.org/pdf/2106.01611">pdf</a>, <a href="https://arxiv.org/ps/2106.01611">ps</a>, <a href="https://arxiv.org/format/2106.01611">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1117/1.JATIS.7.3.037001">10.1117/1.JATIS.7.3.037001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Detailed Design of the Science Operations for the XRISM mission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Terada%2C+Y">Yukikatsu Terada</a>, <a href="/search/astro-ph?searchtype=author&query=Holland%2C+M">Matt Holland</a>, <a href="/search/astro-ph?searchtype=author&query=Loewenstein%2C+M">Michael Loewenstein</a>, <a href="/search/astro-ph?searchtype=author&query=Tashiro%2C+M">Makoto Tashiro</a>, <a href="/search/astro-ph?searchtype=author&query=Takahashi%2C+H">Hiromitsu Takahashi</a>, <a href="/search/astro-ph?searchtype=author&query=Nobukawa%2C+M">Masayoshi Nobukawa</a>, <a href="/search/astro-ph?searchtype=author&query=Mizuno%2C+T">Tsunefumi Mizuno</a>, <a href="/search/astro-ph?searchtype=author&query=Tamura%2C+T">Takayuki Tamura</a>, <a href="/search/astro-ph?searchtype=author&query=Uno%2C+S">Shin'ichiro Uno</a>, <a href="/search/astro-ph?searchtype=author&query=Watanabe%2C+S">Shin Watanabe</a>, <a href="/search/astro-ph?searchtype=author&query=Baluta%2C+C">Chris Baluta</a>, <a href="/search/astro-ph?searchtype=author&query=Burns%2C+L">Laura Burns</a>, <a href="/search/astro-ph?searchtype=author&query=Ebisawa%2C+K">Ken Ebisawa</a>, <a href="/search/astro-ph?searchtype=author&query=Eguchi%2C+S">Satoshi Eguchi</a>, <a href="/search/astro-ph?searchtype=author&query=Fukazawa%2C+Y">Yasushi Fukazawa</a>, <a href="/search/astro-ph?searchtype=author&query=Hayashi%2C+K">Katsuhiro Hayashi</a>, <a href="/search/astro-ph?searchtype=author&query=Iizuka%2C+R">Ryo Iizuka</a>, <a href="/search/astro-ph?searchtype=author&query=Katsuda%2C+S">Satoru Katsuda</a>, <a href="/search/astro-ph?searchtype=author&query=Kitaguchi%2C+T">Takao Kitaguchi</a>, <a href="/search/astro-ph?searchtype=author&query=Kubota%2C+A">Aya Kubota</a>, <a href="/search/astro-ph?searchtype=author&query=Miller%2C+E">Eric Miller</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Nakashima%2C+S">Shinya Nakashima</a>, <a href="/search/astro-ph?searchtype=author&query=Nakazawa%2C+K">Kazuhiro Nakazawa</a>, <a href="/search/astro-ph?searchtype=author&query=Odaka%2C+H">Hirokazu Odaka</a> , et al. (14 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2106.01611v2-abstract-short" style="display: inline;"> XRISM is an X-ray astronomical mission by the JAXA, NASA, ESA and other international participants, that is planned for launch in 2022 (Japanese fiscal year), to quickly restore high-resolution X-ray spectroscopy of astrophysical objects. To enhance the scientific outputs of the mission, the Science Operations Team (SOT) is structured independently from the instrument teams and the Mission Operati… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.01611v2-abstract-full').style.display = 'inline'; document.getElementById('2106.01611v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.01611v2-abstract-full" style="display: none;"> XRISM is an X-ray astronomical mission by the JAXA, NASA, ESA and other international participants, that is planned for launch in 2022 (Japanese fiscal year), to quickly restore high-resolution X-ray spectroscopy of astrophysical objects. To enhance the scientific outputs of the mission, the Science Operations Team (SOT) is structured independently from the instrument teams and the Mission Operations Team. The responsibilities of the SOT are divided into four categories: 1) guest observer program and data distributions, 2) distribution of analysis software and the calibration database, 3) guest observer support activities, and 4) performance verification and optimization activities. As the first step, lessons on the science operations learned from past Japanese X-ray missions are reviewed, and 15 kinds of lessons are identified. Among them, a) the importance of early preparation of the operations from the ground stage, b) construction of an independent team for science operations separate from the instrument development, and c) operations with well-defined duties by appointed members are recognized as key lessons. Then, the team structure and the task division between the mission and science operations are defined; the tasks are shared among Japan, US, and Europe and are performed by three centers, the SOC, SDC, and ESAC, respectively. The SOC is designed to perform tasks close to the spacecraft operations, such as spacecraft planning, quick-look health checks, pre-pipeline processing, etc., and the SDC covers tasks regarding data calibration processing, maintenance of analysis tools, etc. The data-archive and user-support activities are covered both by the SOC and SDC. Finally, the science-operations tasks and tools are defined and prepared before launch. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.01611v2-abstract-full').style.display = 'none'; document.getElementById('2106.01611v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 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">42 pages, 7 figures, 8 table, Accepted for Publication in JATIS (SPIE)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> SPIE JATIS, 7(3), 037001 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2105.13893">arXiv:2105.13893</a> <span> [<a href="https://arxiv.org/pdf/2105.13893">pdf</a>, <a href="https://arxiv.org/format/2105.13893">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac1f1a">10.3847/1538-4357/ac1f1a <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Galactic Extinction: How Many Novae Does it Hide and How Does it Affect the Galactic Nova Rate? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">A. Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">L. Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+J+A">J. A. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">J. Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">K. V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">E. Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Kochanek%2C+C+S">C. S. Kochanek</a>, <a href="/search/astro-ph?searchtype=author&query=Stanek%2C+K+Z">K. Z. Stanek</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=De%2C+K">K. De</a>, <a href="/search/astro-ph?searchtype=author&query=Shappee%2C+B">B. Shappee</a>, <a href="/search/astro-ph?searchtype=author&query=Holoien%2C+T+W+-">T. W. -S. Holoien</a>, <a href="/search/astro-ph?searchtype=author&query=Prieto%2C+J+L">J. L. Prieto</a>, <a href="/search/astro-ph?searchtype=author&query=Thompson%2C+T+A">T. A. Thompson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2105.13893v1-abstract-short" style="display: inline;"> There is a longstanding discrepancy between the observed Galactic classical nova rate of $\sim 10$ yr$^{-1}$ and the predicted rate from Galactic models of $\sim 30$--50 yr$^{-1}$. One explanation for this discrepancy is that many novae are hidden by interstellar extinction, but the degree to which dust can obscure novae is poorly constrained. We use newly available all-sky three-dimensional dust… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.13893v1-abstract-full').style.display = 'inline'; document.getElementById('2105.13893v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2105.13893v1-abstract-full" style="display: none;"> There is a longstanding discrepancy between the observed Galactic classical nova rate of $\sim 10$ yr$^{-1}$ and the predicted rate from Galactic models of $\sim 30$--50 yr$^{-1}$. One explanation for this discrepancy is that many novae are hidden by interstellar extinction, but the degree to which dust can obscure novae is poorly constrained. We use newly available all-sky three-dimensional dust maps to compare the brightness and spatial distribution of known novae to that predicted from relatively simple models in which novae trace Galactic stellar mass. We find that only half ($\sim 48$\%) of novae are expected to be easily detectable ($g \lesssim 15$) with current all-sky optical surveys such as the All-Sky Automated Survey for Supernovae (ASAS-SN). This fraction is much lower than previously estimated, showing that dust does substantially affect nova detection in the optical. By comparing complementary survey results from ASAS-SN, OGLE-IV, and the Palomar Gattini IR-survey in the context of our modeling, we find a tentative Galactic nova rate of $\sim 40$ yr$^{-1}$, though this could decrease to as low as $\sim 30$ yr$^{-1}$ depending on the assumed distribution of novae within the Galaxy. These preliminary estimates will be improved in future work through more sophisticated modeling of nova detection in ASAS-SN and other surveys. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.13893v1-abstract-full').style.display = 'none'; document.getElementById('2105.13893v1-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 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 9 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/2104.09533">arXiv:2104.09533</a> <span> [<a href="https://arxiv.org/pdf/2104.09533">pdf</a>, <a href="https://arxiv.org/format/2104.09533">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s10686-021-09809-6">10.1007/s10686-021-09809-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Time Domain Astronomy with the THESEUS Satellite </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mereghetti%2C+S">S. Mereghetti</a>, <a href="/search/astro-ph?searchtype=author&query=Balman%2C+S">S. Balman</a>, <a href="/search/astro-ph?searchtype=author&query=Caballero-Garcia%2C+M">M. Caballero-Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Del+Santo%2C+M">M. Del Santo</a>, <a href="/search/astro-ph?searchtype=author&query=Doroshenko%2C+V">V. Doroshenko</a>, <a href="/search/astro-ph?searchtype=author&query=Erkut%2C+M+H">M. H. Erkut</a>, <a href="/search/astro-ph?searchtype=author&query=Hanlon%2C+L">L. Hanlon</a>, <a href="/search/astro-ph?searchtype=author&query=Hoeflich%2C+P">P. Hoeflich</a>, <a href="/search/astro-ph?searchtype=author&query=Markowitz%2C+A">A. Markowitz</a>, <a href="/search/astro-ph?searchtype=author&query=Osborne%2C+J+P">J. P. Osborne</a>, <a href="/search/astro-ph?searchtype=author&query=Pian%2C+E">E. Pian</a>, <a href="/search/astro-ph?searchtype=author&query=Sandoval%2C+L+R">L. Rivera Sandoval</a>, <a href="/search/astro-ph?searchtype=author&query=Webb%2C+N">N. Webb</a>, <a href="/search/astro-ph?searchtype=author&query=Amati%2C+L">L. Amati</a>, <a href="/search/astro-ph?searchtype=author&query=Ambrosi%2C+E">E. Ambrosi</a>, <a href="/search/astro-ph?searchtype=author&query=Beardmore%2C+A+P">A. P. Beardmore</a>, <a href="/search/astro-ph?searchtype=author&query=Blain%2C+A">A. Blain</a>, <a href="/search/astro-ph?searchtype=author&query=Bozzo%2C+E">E. Bozzo</a>, <a href="/search/astro-ph?searchtype=author&query=Burderi%2C+L">L. Burderi</a>, <a href="/search/astro-ph?searchtype=author&query=Campana%2C+S">S. Campana</a>, <a href="/search/astro-ph?searchtype=author&query=Casella%2C+P">P. Casella</a>, <a href="/search/astro-ph?searchtype=author&query=D%27A%C3%AC%2C+A">A. D'A矛</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Ammando%2C+F">F. D'Ammando</a>, <a href="/search/astro-ph?searchtype=author&query=De+Colle%2C+F">F. De Colle</a>, <a href="/search/astro-ph?searchtype=author&query=Della+Valle%2C+M">M. Della Valle</a> , et al. (52 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2104.09533v1-abstract-short" style="display: inline;"> THESEUS is a medium size space mission of the European Space Agency, currently under evaluation for a possible launch in 2032. Its main objectives are to investigate the early Universe through the observation of gamma-ray bursts and to study the gravitational waves electromagnetic counterparts and neutrino events. On the other hand, its instruments, which include a wide field of view X-ray (0.3-5… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.09533v1-abstract-full').style.display = 'inline'; document.getElementById('2104.09533v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.09533v1-abstract-full" style="display: none;"> THESEUS is a medium size space mission of the European Space Agency, currently under evaluation for a possible launch in 2032. Its main objectives are to investigate the early Universe through the observation of gamma-ray bursts and to study the gravitational waves electromagnetic counterparts and neutrino events. On the other hand, its instruments, which include a wide field of view X-ray (0.3-5 keV) telescope based on lobster-eye focusing optics and a gamma-ray spectrometer with imaging capabilities in the 2-150 keV range, are also ideal for carrying out unprecedented studies in time domain astrophysics. In addition, the presence onboard of a 70 cm near infrared telescope will allow simultaneous multi-wavelegth studies. Here we present the THESEUS capabilities for studying the time variability of different classes of sources in parallel to, and without affecting, the gamma-ray bursts hunt. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.09533v1-abstract-full').style.display = 'none'; document.getElementById('2104.09533v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to Experimental 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/2103.14800">arXiv:2103.14800</a> <span> [<a href="https://arxiv.org/pdf/2103.14800">pdf</a>, <a href="https://arxiv.org/format/2103.14800">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"> Probing the reach of the Intermediate Polar Cataclysmic Variable Population with Swift J183920.1-045350 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gorgone%2C+N+M">Nicholas M. Gorgone</a>, <a href="/search/astro-ph?searchtype=author&query=Woudt%2C+P+A">Patrick A. Woudt</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D">David Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Kouveliotou%2C+C">Chryssa Kouveliotou</a>, <a href="/search/astro-ph?searchtype=author&query=Gogus%2C+E">Ersin Gogus</a>, <a href="/search/astro-ph?searchtype=author&query=Bellm%2C+E">Eric Bellm</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">Justin D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Horst%2C+A+J">Alexander J. van der Horst</a>, <a href="/search/astro-ph?searchtype=author&query=Baring%2C+M+G">Matthew G. Baring</a>, <a href="/search/astro-ph?searchtype=author&query=Hartmann%2C+D">Dieter Hartmann</a>, <a href="/search/astro-ph?searchtype=author&query=Barrett%2C+P">Paul Barrett</a>, <a href="/search/astro-ph?searchtype=author&query=Cenko%2C+B">Bradley Cenko</a>, <a href="/search/astro-ph?searchtype=author&query=Graham%2C+M">Melissa Graham</a>, <a href="/search/astro-ph?searchtype=author&query=Granot%2C+J">Johnathan Granot</a>, <a href="/search/astro-ph?searchtype=author&query=Harrison%2C+F">Fiona Harrison</a>, <a href="/search/astro-ph?searchtype=author&query=Kennea%2C+J">Jamie Kennea</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Connor%2C+B+M">Brendan M. O'Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Potter%2C+S">Stephen Potter</a>, <a href="/search/astro-ph?searchtype=author&query=Stern%2C+D">Daniel Stern</a>, <a href="/search/astro-ph?searchtype=author&query=Wijers%2C+R">Ralph Wijers</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2103.14800v1-abstract-short" style="display: inline;"> We report on the Swift/XRT Deep Galactic Plane Survey discovery and multi-wavelength follow-up observations of a new intermediate polar Cataclysmic Variable, Swift J183920.1-045350. A 449.7 s spin period is found in Xmm-Newton and NuSTAR data, accompanied by a 459.9 s optical period that is most likely the synodic, or beat period, produced from a 5.6 h orbital period. The orbital period is seen wi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.14800v1-abstract-full').style.display = 'inline'; document.getElementById('2103.14800v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.14800v1-abstract-full" style="display: none;"> We report on the Swift/XRT Deep Galactic Plane Survey discovery and multi-wavelength follow-up observations of a new intermediate polar Cataclysmic Variable, Swift J183920.1-045350. A 449.7 s spin period is found in Xmm-Newton and NuSTAR data, accompanied by a 459.9 s optical period that is most likely the synodic, or beat period, produced from a 5.6 h orbital period. The orbital period is seen with moderate significance in independent long-baseline optical photometry observations with ZTF and SAAO. We find that the source X-ray pulsed fraction decreases with increasing energy. The X-ray spectra are consistent with the presence of an Fe emission line complex with both local and interstellar absorption. In the optical spectra, strong H$伪$, H I, He I and He II emission lines are observed, all common features in magnetic CVs. The source properties are thus typical of known intermediate polars, with the exception of its estimated distance of 2.26$^{+1.93}_{-0.83}$ kpc, which is larger than typical, extending the reach of the CV population in our Galaxy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.14800v1-abstract-full').style.display = 'none'; document.getElementById('2103.14800v1-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 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 9 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/2103.01086">arXiv:2103.01086</a> <span> [<a href="https://arxiv.org/pdf/2103.01086">pdf</a>, <a href="https://arxiv.org/ps/2103.01086">ps</a>, <a href="https://arxiv.org/format/2103.01086">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.nima.2021.165726">10.1016/j.nima.2021.165726 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Surface detectors of the TAx4 experiment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Telescope+Array+Collaboration"> Telescope Array Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Abbasi%2C+R+U">R. U. Abbasi</a>, <a href="/search/astro-ph?searchtype=author&query=Abe%2C+M">M. Abe</a>, <a href="/search/astro-ph?searchtype=author&query=Abu-Zayyad%2C+T">T. Abu-Zayyad</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+M">M. Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Arai%2C+Y">Y. Arai</a>, <a href="/search/astro-ph?searchtype=author&query=Barcikowski%2C+E">E. Barcikowski</a>, <a href="/search/astro-ph?searchtype=author&query=Belz%2C+J+W">J. W. Belz</a>, <a href="/search/astro-ph?searchtype=author&query=Bergman%2C+D+R">D. R. Bergman</a>, <a href="/search/astro-ph?searchtype=author&query=Blake%2C+S+A">S. A. Blake</a>, <a href="/search/astro-ph?searchtype=author&query=Cady%2C+R">R. Cady</a>, <a href="/search/astro-ph?searchtype=author&query=Cheon%2C+B+G">B. G. Cheon</a>, <a href="/search/astro-ph?searchtype=author&query=Chiba%2C+J">J. Chiba</a>, <a href="/search/astro-ph?searchtype=author&query=Chikawa%2C+M">M. Chikawa</a>, <a href="/search/astro-ph?searchtype=author&query=Fujii%2C+T">T. Fujii</a>, <a href="/search/astro-ph?searchtype=author&query=Fujisue%2C+K">K. Fujisue</a>, <a href="/search/astro-ph?searchtype=author&query=Fujita%2C+K">K. Fujita</a>, <a href="/search/astro-ph?searchtype=author&query=Fujiwara%2C+R">R. Fujiwara</a>, <a href="/search/astro-ph?searchtype=author&query=Fukushima%2C+M">M. Fukushima</a>, <a href="/search/astro-ph?searchtype=author&query=Fukushima%2C+R">R. Fukushima</a>, <a href="/search/astro-ph?searchtype=author&query=Furlich%2C+G">G. Furlich</a>, <a href="/search/astro-ph?searchtype=author&query=Hanlon%2C+W">W. Hanlon</a>, <a href="/search/astro-ph?searchtype=author&query=Hayashi%2C+M">M. Hayashi</a>, <a href="/search/astro-ph?searchtype=author&query=Hayashida%2C+N">N. Hayashida</a>, <a href="/search/astro-ph?searchtype=author&query=Hibino%2C+K">K. Hibino</a> , et al. (124 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="2103.01086v1-abstract-short" style="display: inline;"> Telescope Array (TA) is the largest ultrahigh energy cosmic-ray (UHECR) observatory in the Northern Hemisphere. It explores the origin of UHECRs by measuring their energy spectrum, arrival-direction distribution, and mass composition using a surface detector (SD) array covering approximately 700 km$^2$ and fluorescence detector (FD) stations. TA has found evidence for a cluster of cosmic rays with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.01086v1-abstract-full').style.display = 'inline'; document.getElementById('2103.01086v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.01086v1-abstract-full" style="display: none;"> Telescope Array (TA) is the largest ultrahigh energy cosmic-ray (UHECR) observatory in the Northern Hemisphere. It explores the origin of UHECRs by measuring their energy spectrum, arrival-direction distribution, and mass composition using a surface detector (SD) array covering approximately 700 km$^2$ and fluorescence detector (FD) stations. TA has found evidence for a cluster of cosmic rays with energies greater than 57 EeV. In order to confirm this evidence with more data, it is necessary to increase the data collection rate.We have begun building an expansion of TA that we call TAx4. In this paper, we explain the motivation, design, technical features, and expected performance of the TAx4 SD. We also present TAx4's current status and examples of the data that have already been collected. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.01086v1-abstract-full').style.display = 'none'; document.getElementById('2103.01086v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages, 17 figures, submitted to Nuclear Inst. and Methods in Physics Research, A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.12239">arXiv:2101.12239</a> <span> [<a href="https://arxiv.org/pdf/2101.12239">pdf</a>, <a href="https://arxiv.org/format/2101.12239">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </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/abe53d">10.3847/1538-4357/abe53d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Classical Novae Masquerading as Dwarf Novae? Outburst Properties of Cataclysmic Variables with ASAS-SN </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">Adam Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">Jay Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">Elias Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">Kirill V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Jayasinghe%2C+T">Tharindu Jayasinghe</a>, <a href="/search/astro-ph?searchtype=author&query=Kochanek%2C+C+S">Chris S. Kochanek</a>, <a href="/search/astro-ph?searchtype=author&query=Schmeer%2C+P">Patrick Schmeer</a>, <a href="/search/astro-ph?searchtype=author&query=Stanek%2C+K+Z">Krzysztof Z. Stanek</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Shappee%2C+B">Ben Shappee</a>, <a href="/search/astro-ph?searchtype=author&query=Way%2C+Z">Zachary Way</a>, <a href="/search/astro-ph?searchtype=author&query=Basinger%2C+C">Connor Basinger</a>, <a href="/search/astro-ph?searchtype=author&query=Holoien%2C+T+W+-">Tom W. -S. Holoien</a>, <a href="/search/astro-ph?searchtype=author&query=Prieto%2C+J+L">Jose L. Prieto</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2101.12239v1-abstract-short" style="display: inline;"> The unprecedented sky coverage and observing cadence of the All-Sky Automated Survey for SuperNovae (ASAS-SN) has resulted in the discovery and continued monitoring of a large sample of Galactic transients. The vast majority of these are accretion-powered dwarf nova outbursts in cataclysmic variable systems, but a small subset are thermonuclear-powered classical novae. Despite improved monitoring… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.12239v1-abstract-full').style.display = 'inline'; document.getElementById('2101.12239v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.12239v1-abstract-full" style="display: none;"> The unprecedented sky coverage and observing cadence of the All-Sky Automated Survey for SuperNovae (ASAS-SN) has resulted in the discovery and continued monitoring of a large sample of Galactic transients. The vast majority of these are accretion-powered dwarf nova outbursts in cataclysmic variable systems, but a small subset are thermonuclear-powered classical novae. Despite improved monitoring of the Galaxy for novae from ASAS-SN and other surveys, the observed Galactic nova rate is still lower than predictions. One way classical novae could be missed is if they are confused with the much larger population of dwarf novae. Here, we examine the properties of 1617 dwarf nova outbursts detected by ASAS-SN and compare them to classical novae. We find that the mean classical nova brightens by ~11 magnitudes during outburst, while the mean dwarf nova brightens by only ~5 magnitudes, with the outburst amplitude distributions overlapping by roughly 15%. For the first time, we show that the amplitude of an outburst and the time it takes to decline by two magnitudes from maximum are positively correlated for dwarf nova outbursts. For classical novae, we find that these quantities are negatively correlated, but only weakly, compared to the strong anti-correlation of these quantities found in some previous work. We show that, even if located at large distances, only a small number of putative dwarf novae could be mis-classified classical novae suggesting that there is minimal confusion between these populations. Future spectroscopic follow-up of these candidates can show whether any are indeed classical novae. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.12239v1-abstract-full').style.display = 'none'; document.getElementById('2101.12239v1-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 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 11 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/2012.00160">arXiv:2012.00160</a> <span> [<a href="https://arxiv.org/pdf/2012.00160">pdf</a>, <a href="https://arxiv.org/format/2012.00160">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/ac15f8">10.3847/1538-4357/ac15f8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Comprehensive X-ray Report on AT2019wey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Yao%2C+Y">Yuhan Yao</a>, <a href="/search/astro-ph?searchtype=author&query=Kulkarni%2C+S+R">S. R. Kulkarni</a>, <a href="/search/astro-ph?searchtype=author&query=Gendreau%2C+K+C">K. C. Gendreau</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=Enoto%2C+T">Teruaki Enoto</a>, <a href="/search/astro-ph?searchtype=author&query=Grefenstette%2C+B+W">Brian W. Grefenstette</a>, <a href="/search/astro-ph?searchtype=author&query=Marshall%2C+H+L">Herman L. Marshall</a>, <a href="/search/astro-ph?searchtype=author&query=Garc%C3%ADa%2C+J+A">Javier A. Garc铆a</a>, <a href="/search/astro-ph?searchtype=author&query=Ludlam%2C+R+M">R. M. Ludlam</a>, <a href="/search/astro-ph?searchtype=author&query=Pike%2C+S+N">Sean N. Pike</a>, <a href="/search/astro-ph?searchtype=author&query=Ng%2C+M">Mason Ng</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+L">Liang Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Altamirano%2C+D">Diego Altamirano</a>, <a href="/search/astro-ph?searchtype=author&query=Jaodand%2C+A">Amruta Jaodand</a>, <a href="/search/astro-ph?searchtype=author&query=Cenko%2C+S+B">S. Bradley Cenko</a>, <a href="/search/astro-ph?searchtype=author&query=Remillard%2C+R+A">Ronald A. Remillard</a>, <a href="/search/astro-ph?searchtype=author&query=Steiner%2C+J+F">James F. Steiner</a>, <a href="/search/astro-ph?searchtype=author&query=Negoro%2C+H">Hitoshi Negoro</a>, <a href="/search/astro-ph?searchtype=author&query=Brightman%2C+M">Murray Brightman</a>, <a href="/search/astro-ph?searchtype=author&query=Lien%2C+A">Amy Lien</a>, <a href="/search/astro-ph?searchtype=author&query=Wolff%2C+M+T">Michael T. Wolff</a>, <a href="/search/astro-ph?searchtype=author&query=Ray%2C+P+S">Paul S. Ray</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Wadiasingh%2C+Z">Zorawar Wadiasingh</a>, <a href="/search/astro-ph?searchtype=author&query=Arzoumanian%2C+Z">Zaven Arzoumanian</a> , et al. (3 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="2012.00160v2-abstract-short" style="display: inline;"> Here, we present MAXI, SWIFT, NICER, NuSTAR and Chandra observations of the X-ray transient AT2019wey (SRGA J043520.9+552226, SRGE J043523.3+552234). From spectral and timing analyses we classify it as a Galactic low-mass X-ray binary (LMXB) with a black hole (BH) or neutron star (NS) accretor. AT2019wey stayed in the low/hard state (LHS) from 2019 December to 2020 August 21, and the hard-intermed… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.00160v2-abstract-full').style.display = 'inline'; document.getElementById('2012.00160v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.00160v2-abstract-full" style="display: none;"> Here, we present MAXI, SWIFT, NICER, NuSTAR and Chandra observations of the X-ray transient AT2019wey (SRGA J043520.9+552226, SRGE J043523.3+552234). From spectral and timing analyses we classify it as a Galactic low-mass X-ray binary (LMXB) with a black hole (BH) or neutron star (NS) accretor. AT2019wey stayed in the low/hard state (LHS) from 2019 December to 2020 August 21, and the hard-intermediate state (HIMS) from 2020 August 21 to 2020 November. For the first six months of the LHS, AT2019wey had a flux of $\sim 1$ mCrab, and displayed a power-law X-ray spectrum with photon index $螕= 1.8$. From 2020 June to August, it brightened to $\sim 20$ mCrab. Spectral features characteristic of relativistic reflection became prominent. On 2020 August 21, the source left the "hard line" on the rms--intensity diagram, and transitioned from LHS to HIMS. The thermal disk component became comparable to the power-law component. A low-frequency quasi-periodic oscillation (QPO) was observed. The QPO central frequency increased as the spectrum softened. No evidence of pulsation was detected. We are not able to decisively determine the nature of the accretor (BH or NS). However, the BH option is favored by the position of this source on the $螕$--$L_{\rm X}$, $L_{\rm radio}$--$L_{\rm X}$, and $L_{\rm opt}$--$L_{\rm X}$ diagrams. We find the BH candidate XTE J1752-223 to be an analog of AT2019wey. Both systems display outbursts with long plateau phases in the hard states. We conclude by noting the potential of SRG in finding new members of this emerging class of low luminosity and long-duration LMXB outbursts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.00160v2-abstract-full').style.display = 'none'; document.getElementById('2012.00160v2-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 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.15930">arXiv:2010.15930</a> <span> [<a href="https://arxiv.org/pdf/2010.15930">pdf</a>, <a href="https://arxiv.org/format/2010.15930">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/abe547">10.3847/1538-4357/abe547 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Surveying the X-ray Behavior of Novae as They Emit $纬$-rays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gordon%2C+A+C">Alexa C. Gordon</a>, <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">Elias Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Page%2C+K+L">Kim L. Page</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+K">Kwan-Lok Li</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">Kirill V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Seitz%2C+J">Joseph Seitz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2010.15930v1-abstract-short" style="display: inline;"> The detection of GeV $纬$-ray emission from Galactic novae by $Fermi$-LAT has become routine since 2010, and is generally associated with shocks internal to the nova ejecta. These shocks are also expected to heat plasma to $\sim 10^7$ K, resulting in detectable X-ray emission. In this paper, we investigate 13 $纬$-ray emitting novae observed with the Neil Gehrels $Swift$ Observatory, searching for 1… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.15930v1-abstract-full').style.display = 'inline'; document.getElementById('2010.15930v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.15930v1-abstract-full" style="display: none;"> The detection of GeV $纬$-ray emission from Galactic novae by $Fermi$-LAT has become routine since 2010, and is generally associated with shocks internal to the nova ejecta. These shocks are also expected to heat plasma to $\sim 10^7$ K, resulting in detectable X-ray emission. In this paper, we investigate 13 $纬$-ray emitting novae observed with the Neil Gehrels $Swift$ Observatory, searching for 1-10 keV X-ray emission concurrent with $纬$-ray detections. We also analyze $纬$-ray observations of novae V407 Lup (2016) and V357 Mus (2018). We find that most novae do eventually show X-ray evidence of hot shocked plasma, but not until the $纬$-rays have faded below detectability. We suggest that the delayed rise of the X-ray emission is due to large absorbing columns and/or X-ray suppression by corrugated shock fronts. The only nova in our sample with a concurrent X-ray/$纬$-ray detection is also the only embedded nova (V407 Cyg). This exception supports a scenario where novae with giant companions produce shocks with external circumbinary material and are characterized by lower density environments, in comparison with novae with dwarf companions where shocks occur internal to the dense ejecta. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.15930v1-abstract-full').style.display = 'none'; document.getElementById('2010.15930v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 19 figures, submitted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.07481">arXiv:2010.07481</a> <span> [<a href="https://arxiv.org/pdf/2010.07481">pdf</a>, <a href="https://arxiv.org/format/2010.07481">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/abc3bb">10.3847/1538-4357/abc3bb <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Early spectral evolution of classical novae: consistent evidence for multiple distinct outflows </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aydi%2C+E">E. Aydi</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">L. Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Izzo%2C+L">L. Izzo</a>, <a href="/search/astro-ph?searchtype=author&query=Harvey%2C+E+J">E. J. Harvey</a>, <a href="/search/astro-ph?searchtype=author&query=Leahy-McGregor%2C+J">J. Leahy-McGregor</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">J. Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Buckley%2C+D+A+H">D. A. H. Buckley</a>, <a href="/search/astro-ph?searchtype=author&query=Sokolovsky%2C+K+V">K. V. Sokolovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Kawash%2C+A">A. Kawash</a>, <a href="/search/astro-ph?searchtype=author&query=Kochanek%2C+C+S">C. S. Kochanek</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">J. D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=Metzger%2C+B+D">B. D. Metzger</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Orio%2C+M">M. Orio</a>, <a href="/search/astro-ph?searchtype=author&query=Shappee%2C+B+J">B. J. Shappee</a>, <a href="/search/astro-ph?searchtype=author&query=Shishkovsky%2C+L">L. Shishkovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Steinberg%2C+E">E. Steinberg</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=Sokoloski%2C+J+L">J. L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Walter%2C+F+M">F. M. Walter</a>, <a href="/search/astro-ph?searchtype=author&query=Woudt%2C+P+A">P. A. Woudt</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2010.07481v1-abstract-short" style="display: inline;"> The physical mechanism driving mass ejection during a nova eruption is still poorly understood. Possibilities include ejection in a single ballistic event, a common envelope interaction, a continuous wind, or some combination of these processes. Here we present a study of 12 Galactic novae, for which we have pre-maximum high-resolution spectroscopy. All 12 novae show the same spectral evolution. B… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.07481v1-abstract-full').style.display = 'inline'; document.getElementById('2010.07481v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.07481v1-abstract-full" style="display: none;"> The physical mechanism driving mass ejection during a nova eruption is still poorly understood. Possibilities include ejection in a single ballistic event, a common envelope interaction, a continuous wind, or some combination of these processes. Here we present a study of 12 Galactic novae, for which we have pre-maximum high-resolution spectroscopy. All 12 novae show the same spectral evolution. Before optical peak, they show a slow P Cygni component. After peak a fast component quickly arises, while the slow absorption remains superimposed on top of it, implying the presence of at least two physically distinct flows. For novae with high-cadence monitoring, a third, intermediate-velocity component is also observed. These observations are consistent with a scenario where the slow component is associated with the initial ejection of the accreted material and the fast component with a radiation-driven wind from the white dwarf. When these flows interact, the slow flow is swept up by the fast flow, producing the intermediate component. These colliding flows may produce the gamma-ray emission observed in some novae. Our spectra also show that the transient heavy element absorption lines seen in some novae have the same velocity structure and evolution as the other lines in the spectrum, implying an association with the nova ejecta rather than a pre-existing circumbinary reservoir of gas or material ablated from the secondary. While this basic scenario appears to qualitatively reproduce multi-wavelength observations of classical novae, substantial theoretical and observational work is still needed to untangle the rich diversity of nova properties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.07481v1-abstract-full').style.display = 'none'; document.getElementById('2010.07481v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">39 pages, 35 figures, submitted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.14327">arXiv:2009.14327</a> <span> [<a href="https://arxiv.org/pdf/2009.14327">pdf</a>, <a href="https://arxiv.org/format/2009.14327">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1029/2019JD031940">10.1029/2019JD031940 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observations of the Origin of Downward Terrestrial Gamma-Ray Flashes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Belz%2C+J+W">J. W. Belz</a>, <a href="/search/astro-ph?searchtype=author&query=Krehbiel%2C+P+R">P. R. Krehbiel</a>, <a href="/search/astro-ph?searchtype=author&query=Remington%2C+J">J. Remington</a>, <a href="/search/astro-ph?searchtype=author&query=Stanley%2C+M+A">M. A. Stanley</a>, <a href="/search/astro-ph?searchtype=author&query=Abbasi%2C+R+U">R. U. Abbasi</a>, <a href="/search/astro-ph?searchtype=author&query=LeVon%2C+R">R. LeVon</a>, <a href="/search/astro-ph?searchtype=author&query=Rison%2C+W">W. Rison</a>, <a href="/search/astro-ph?searchtype=author&query=Rodeheffer%2C+D">D. Rodeheffer</a>, <a href="/search/astro-ph?searchtype=author&query=Collaboration%2C+t+T+A+S">the Telescope Array Scientific Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=%3A"> :</a>, <a href="/search/astro-ph?searchtype=author&query=Abu-Zayyad%2C+T">T. Abu-Zayyad</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+M">M. Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Barcikowski%2C+E">E. Barcikowski</a>, <a href="/search/astro-ph?searchtype=author&query=Bergman%2C+D+R">D. R. Bergman</a>, <a href="/search/astro-ph?searchtype=author&query=Blake%2C+S+A">S. A. Blake</a>, <a href="/search/astro-ph?searchtype=author&query=Byrne%2C+M">M. Byrne</a>, <a href="/search/astro-ph?searchtype=author&query=Cady%2C+R">R. Cady</a>, <a href="/search/astro-ph?searchtype=author&query=Cheon%2C+B+G">B. G. Cheon</a>, <a href="/search/astro-ph?searchtype=author&query=Chikawa%2C+M">M. Chikawa</a>, <a href="/search/astro-ph?searchtype=author&query=di+Matteo%2C+A">A. di Matteo</a>, <a href="/search/astro-ph?searchtype=author&query=Fujii%2C+T">T. Fujii</a>, <a href="/search/astro-ph?searchtype=author&query=Fujita%2C+K">K. Fujita</a>, <a href="/search/astro-ph?searchtype=author&query=Fujiwara%2C+R">R. Fujiwara</a>, <a href="/search/astro-ph?searchtype=author&query=Fukushima%2C+M">M. Fukushima</a>, <a href="/search/astro-ph?searchtype=author&query=Furlich%2C+G">G. Furlich</a> , et al. (116 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.14327v2-abstract-short" style="display: inline;"> In this paper we report the first close, high-resolution observations of downward-directed terrestrial gamma-ray flashes (TGFs) detected by the large-area Telescope Array cosmic ray observatory, obtained in conjunction with broadband VHF interferometer and fast electric field change measurements of the parent discharge. The results show that the TGFs occur during strong initial breakdown pulses (I… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.14327v2-abstract-full').style.display = 'inline'; document.getElementById('2009.14327v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.14327v2-abstract-full" style="display: none;"> In this paper we report the first close, high-resolution observations of downward-directed terrestrial gamma-ray flashes (TGFs) detected by the large-area Telescope Array cosmic ray observatory, obtained in conjunction with broadband VHF interferometer and fast electric field change measurements of the parent discharge. The results show that the TGFs occur during strong initial breakdown pulses (IBPs) in the first few milliseconds of negative cloud-to-ground and low-altitude intracloud flashes, and that the IBPs are produced by a newly-identified streamer-based discharge process called fast negative breakdown. The observations indicate the relativistic runaway electron avalanches (RREAs) responsible for producing the TGFs are initiated by embedded spark-like transient conducting events (TCEs) within the fast streamer system, and potentially also by individual fast streamers themselves. The TCEs are inferred to be the cause of impulsive sub-pulses that are characteristic features of classic IBP sferics. Additional development of the avalanches would be facilitated by the enhanced electric field ahead of the advancing front of the fast negative breakdown. In addition to showing the nature of IBPs and their enigmatic sub-pulses, the observations also provide a possible explanation for the unsolved question of how the streamer to leader transition occurs during the initial negative breakdown, namely as a result of strong currents flowing in the final stage of successive IBPs, extending backward through both the IBP itself and the negative streamer breakdown preceding the IBP. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.14327v2-abstract-full').style.display = 'none'; document.getElementById('2009.14327v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">Typo fixed and reference added. Manuscript is 36 pages. Supplemental Information is 42 pages. This paper is to be published in the Journal of Geophysical Research: Atmospheres. Online data repository: Open Science Framework DOI: 10.17605/OSF.IO/Z3XDA</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.11902">arXiv:2009.11902</a> <span> [<a href="https://arxiv.org/pdf/2009.11902">pdf</a>, <a href="https://arxiv.org/ps/2009.11902">ps</a>, <a href="https://arxiv.org/format/2009.11902">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/abbb2c">10.3847/2041-8213/abbb2c <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Increasing activity in T CrB suggests nova eruption is impending </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Luna%2C+G+J+M">Gerardo J. M. Luna</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">J. L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Kuin%2C+P">P. Kuin</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="2009.11902v1-abstract-short" style="display: inline;"> Estimates of the accretion rate in symbiotic recurrent novae (RNe) often fall short of theoretical expectations by orders of magnitude. This apparent discrepancy can be resolved if the accumulation of mass by the white dwarf (WD) is highly sporadic, and most observations are performed during low states. Here we use a reanalysis of archival data from the Digital Access to a Sky Century @Harvard (DA… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.11902v1-abstract-full').style.display = 'inline'; document.getElementById('2009.11902v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.11902v1-abstract-full" style="display: none;"> Estimates of the accretion rate in symbiotic recurrent novae (RNe) often fall short of theoretical expectations by orders of magnitude. This apparent discrepancy can be resolved if the accumulation of mass by the white dwarf (WD) is highly sporadic, and most observations are performed during low states. Here we use a reanalysis of archival data from the Digital Access to a Sky Century @Harvard (DASCH) survey to argue that the most recent nova eruption in symbiotic RN T CrB, in 1946, occurred during -- and was therefore triggered by -- a transient accretion high state. Based on similarities in the optical light curve around 1946 and the time of the prior eruption, in 1866, we suggest that the WD in T CrB accumulates most of the fuel needed to ignite the thermonuclear runaways (TNRs) during accretion high states. A natural origin for such states is dwarf-nova like accretion-disk instabilities, which are expected in the presumably large disks in symbiotic binaries. The timing of the TNRs in symbiotic RNe could thus be set by the stability properties of their accretion disks. T CrB is in the midst of an accretion high state like the ones we posit led to the past two nova eruptions. Combined with the approach of the time at which a TNR would be expected based on the 80-year interval between the prior two novae ($2026 \pm$3), the current accretion high state increases the likelihood of a TNR occurring in T CrB in the next few years. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.11902v1-abstract-full').style.display = 'none'; document.getElementById('2009.11902v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted in ApJL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2008.09684">arXiv:2008.09684</a> <span> [<a href="https://arxiv.org/pdf/2008.09684">pdf</a>, <a href="https://arxiv.org/format/2008.09684">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/staa2592">10.1093/mnras/staa2592 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measuring the masses of magnetic white dwarfs: A NuSTAR Legacy Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Shaw%2C+A+W">A. W. Shaw</a>, <a href="/search/astro-ph?searchtype=author&query=Heinke%2C+C+O">C. O. Heinke</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">K. Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Tomsick%2C+J+A">J. A. Tomsick</a>, <a href="/search/astro-ph?searchtype=author&query=Doroshenko%2C+V">V. Doroshenko</a>, <a href="/search/astro-ph?searchtype=author&query=Suleimanov%2C+V+F">V. F. Suleimanov</a>, <a href="/search/astro-ph?searchtype=author&query=Buisson%2C+D+J+K">D. J. K. Buisson</a>, <a href="/search/astro-ph?searchtype=author&query=Gandhi%2C+P">P. Gandhi</a>, <a href="/search/astro-ph?searchtype=author&query=Grefenstette%2C+B+W">B. W. Grefenstette</a>, <a href="/search/astro-ph?searchtype=author&query=Hare%2C+J">J. Hare</a>, <a href="/search/astro-ph?searchtype=author&query=Jiang%2C+J">J. Jiang</a>, <a href="/search/astro-ph?searchtype=author&query=Ludlam%2C+R+M">R. M. Ludlam</a>, <a href="/search/astro-ph?searchtype=author&query=Rana%2C+V">V. Rana</a>, <a href="/search/astro-ph?searchtype=author&query=Sivakoff%2C+G+R">G. R. Sivakoff</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="2008.09684v2-abstract-short" style="display: inline;"> The hard X-ray spectrum of magnetic cataclysmic variables can be modelled to provide a measurement of white dwarf mass. This method is complementary to radial velocity measurements, which depend on the (typically rather uncertain) binary inclination. Here we present results from a Legacy Survey of 19 magnetic cataclysmic variables with NuSTAR. We fit accretion column models to their 20-78 keV spec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.09684v2-abstract-full').style.display = 'inline'; document.getElementById('2008.09684v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2008.09684v2-abstract-full" style="display: none;"> The hard X-ray spectrum of magnetic cataclysmic variables can be modelled to provide a measurement of white dwarf mass. This method is complementary to radial velocity measurements, which depend on the (typically rather uncertain) binary inclination. Here we present results from a Legacy Survey of 19 magnetic cataclysmic variables with NuSTAR. We fit accretion column models to their 20-78 keV spectra and derive the white dwarf masses, finding a weighted average $\bar{M}_{\rm WD}=0.77\pm0.02$ $M_{\odot}$, with a standard deviation $蟽=0.10$ $M_{\odot}$, when we include the masses derived from previous NuSTAR observations of seven additional magnetic cataclysmic variables. We find that the mass distribution of accreting magnetic white dwarfs is consistent with that of white dwarfs in non-magnetic cataclysmic variables. Both peak at a higher mass than the distributions of isolated white dwarfs and post-common-envelope binaries. We speculate as to why this might be the case, proposing that consequential angular momentum losses may play a role in accreting magnetic white dwarfs and/or that our knowledge of how the white dwarf mass changes over accretion-nova cycles may also be incomplete. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.09684v2-abstract-full').style.display = 'none'; document.getElementById('2008.09684v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 August, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 August, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">14 pages. 5 figures in main paper, 1 figure in appendix. 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/2007.15702">arXiv:2007.15702</a> <span> [<a href="https://arxiv.org/pdf/2007.15702">pdf</a>, <a href="https://arxiv.org/ps/2007.15702">ps</a>, <a href="https://arxiv.org/format/2007.15702">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/staa3367">10.1093/mnras/staa3367 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> X-ray evolution of the nova V959 Mon suggests a delayed ejection and a non-radiative shock </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nelson%2C+T">Thomas Nelson</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</a>, <a href="/search/astro-ph?searchtype=author&query=Sokoloski%2C+J+L">Jennifer L. Sokoloski</a>, <a href="/search/astro-ph?searchtype=author&query=Linford%2C+J+D">Justin D. Linford</a>, <a href="/search/astro-ph?searchtype=author&query=Finzell%2C+T">Thomas Finzell</a>, <a href="/search/astro-ph?searchtype=author&query=Mioduszewski%2C+A+J">Amy J. Mioduszewski</a>, <a href="/search/astro-ph?searchtype=author&query=Rupen%2C+M+P">Michael P. Rupen</a>, <a href="/search/astro-ph?searchtype=author&query=Weston%2C+J">Jennifer Weston</a>, <a href="/search/astro-ph?searchtype=author&query=de+Oliveira%2C+R+L">Raimundo Lopes de Oliveira</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="2007.15702v2-abstract-short" style="display: inline;"> X-ray observations of shocked gas in novae can provide a useful probe of the dynamics of the ejecta. Here we report on X-ray observations of the nova V959 Mon, which was also detected in GeV gamma-rays with the Fermi satellite. We find that the X-ray spectra are consistent with a two-temperature plasma model with non-solar abundances. We interpret the X-rays as due to shock interaction between the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.15702v2-abstract-full').style.display = 'inline'; document.getElementById('2007.15702v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.15702v2-abstract-full" style="display: none;"> X-ray observations of shocked gas in novae can provide a useful probe of the dynamics of the ejecta. Here we report on X-ray observations of the nova V959 Mon, which was also detected in GeV gamma-rays with the Fermi satellite. We find that the X-ray spectra are consistent with a two-temperature plasma model with non-solar abundances. We interpret the X-rays as due to shock interaction between the slow equatorial torus and the fast polar outflow that were inferred from radio observations of V959 Mon. We further propose that the hotter component, responsible for most of the flux, is from the reverse shock driven into the fast outflow. We find a systematic drop in the column density of the absorber between Days 60 and 140, consistent with the expectations for such a picture. We present intriguing evidence for a delay of around 40 days in the expulsion of the ejecta from the central binary. Moreover, we infer a relatively small (a few times 10$^{-6}$ Msun) ejecta mass ahead of the shock, considerably lower than the mass of 10$^4$ K gas inferred from radio observations. Finally, we infer that the dominant X-ray shock was likely not radiative at the time of our observations, and that the shock power was considerably higher than the observed X-ray luminosity. It is unclear why high X-ray luminosity, closer to the inferred shock power, is never seen in novae at early times, when the shock is expected to have high enough density to be radiative. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.15702v2-abstract-full').style.display = 'none'; document.getElementById('2007.15702v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 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">15 pages, 7 figures; accepted for publication in Monthly Notices of the Royal Astronomical Society</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.13932">arXiv:2007.13932</a> <span> [<a href="https://arxiv.org/pdf/2007.13932">pdf</a>, <a href="https://arxiv.org/ps/2007.13932">ps</a>, <a href="https://arxiv.org/format/2007.13932">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/aba618">10.3847/2041-8213/aba618 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> CTCV J2056-3014: An X-ray-faint Intermediate Polar Harboring An Extremely Fast-spinning White Dwarf </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=de+Oliveira%2C+R+L">Raimundo Lopes de Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=Bruch%2C+A">Albert Bruch</a>, <a href="/search/astro-ph?searchtype=author&query=Rodrigues%2C+.+C+V">. Claudia Vilega Rodrigues</a>, <a href="/search/astro-ph?searchtype=author&query=de+Oliveira%2C+A+S">Alexandre Soares de Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=Mukai%2C+K">Koji Mukai</a>, <a href="/search/astro-ph?searchtype=author&query=-"> -</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="2007.13932v1-abstract-short" style="display: inline;"> We report on XMM-Newton X-ray observations that reveal CTCV J2056-3014 to be an unusual accretion-powered, intermediate polar (IP) system. It is a member of the class of X-ray-faint IPs whose space density remains unconstrained but potentially very high, with L$_{x,0.3-12 keV}$ of 1.8$\times$10$^{31}$ erg s$^{-1}$. We discovered a coherent 29.6s pulsation in X-rays that was also revealed in our re… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.13932v1-abstract-full').style.display = 'inline'; document.getElementById('2007.13932v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.13932v1-abstract-full" style="display: none;"> We report on XMM-Newton X-ray observations that reveal CTCV J2056-3014 to be an unusual accretion-powered, intermediate polar (IP) system. It is a member of the class of X-ray-faint IPs whose space density remains unconstrained but potentially very high, with L$_{x,0.3-12 keV}$ of 1.8$\times$10$^{31}$ erg s$^{-1}$. We discovered a coherent 29.6s pulsation in X-rays that was also revealed in our reanalysis of published optical data, showing that the system harbors the fastest-spinning, securely known white dwarf (WD) so far. There is no substantial X-ray absorption in the system. Accretion occurs at a modest rate ($\sim$ 6$\times$10$^{-12}$ M$_{\odot}$ yr$^{-1}$) in a tall shock above the WD, while the star seems to be spinning in equilibrium and to have low magnetic fields. Further studies of CTCV J2056-3014 potentially have broad implications on the origin of magnetic fields in WDs, on the population and evolution of magnetic cataclysmic variables, and also on the physics of matter around rapidly rotating magnetic WDs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.13932v1-abstract-full').style.display = 'none'; document.getElementById('2007.13932v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 July, 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">Accepted for publication in ApJL, 5 pages, 2 figures</span> </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" 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