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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/2402.15229">arXiv:2402.15229</a> <span> [<a href="https://arxiv.org/pdf/2402.15229">pdf</a>, <a href="https://arxiv.org/format/2402.15229">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.astropartphys.2024.102944">10.1016/j.astropartphys.2024.102944 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Systematic effects on a Compton polarimeter at the focus of an X-ray mirror </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aoyagi%2C+M">M. Aoyagi</a>, <a href="/search/astro-ph?searchtype=author&query=Bose%2C+R+G">R. G. Bose</a>, <a href="/search/astro-ph?searchtype=author&query=Chun%2C+S">S. Chun</a>, <a href="/search/astro-ph?searchtype=author&query=Gau%2C+E">E. Gau</a>, <a href="/search/astro-ph?searchtype=author&query=Hu%2C+K">K. Hu</a>, <a href="/search/astro-ph?searchtype=author&query=Ishiwata%2C+K">K. Ishiwata</a>, <a href="/search/astro-ph?searchtype=author&query=Iyer%2C+N+K">N. K. Iyer</a>, <a href="/search/astro-ph?searchtype=author&query=Kislat%2C+F">F. Kislat</a>, <a href="/search/astro-ph?searchtype=author&query=Kiss%2C+M">M. Kiss</a>, <a href="/search/astro-ph?searchtype=author&query=Klepper%2C+K">K. Klepper</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">H. Krawczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Lisalda%2C+L">L. Lisalda</a>, <a href="/search/astro-ph?searchtype=author&query=Maeda%2C+Y">Y. Maeda</a>, <a href="/search/astro-ph?searchtype=author&query=Malmborg%2C+F+a">F. af Malmborg</a>, <a href="/search/astro-ph?searchtype=author&query=Matsumoto%2C+H">H. Matsumoto</a>, <a href="/search/astro-ph?searchtype=author&query=Miyamoto%2C+A">A. Miyamoto</a>, <a href="/search/astro-ph?searchtype=author&query=Miyazawa%2C+T">T. Miyazawa</a>, <a href="/search/astro-ph?searchtype=author&query=Pearce%2C+M">M. Pearce</a>, <a href="/search/astro-ph?searchtype=author&query=Rauch%2C+B+F">B. F. Rauch</a>, <a href="/search/astro-ph?searchtype=author&query=Cavero%2C+N+R">N. Rodriguez Cavero</a>, <a href="/search/astro-ph?searchtype=author&query=Spooner%2C+S">S. Spooner</a>, <a href="/search/astro-ph?searchtype=author&query=Takahashi%2C+H">H. Takahashi</a>, <a href="/search/astro-ph?searchtype=author&query=Uchida%2C+Y">Y. Uchida</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+T">A. T. West</a>, <a href="/search/astro-ph?searchtype=author&query=Wimalasena%2C+K">K. Wimalasena</a> , et al. (1 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.15229v1-abstract-short" style="display: inline;"> XL-Calibur is a balloon-borne Compton polarimeter for X-rays in the $\sim$15-80 keV range. Using an X-ray mirror with a 12 m focal length for collecting photons onto a beryllium scattering rod surrounded by CZT detectors, a minimum-detectable polarization as low as $\sim$3% is expected during a 24-hour on-target observation of a 1 Crab source at 45$^{\circ}$ elevation. Systematic effects alter the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.15229v1-abstract-full').style.display = 'inline'; document.getElementById('2402.15229v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.15229v1-abstract-full" style="display: none;"> XL-Calibur is a balloon-borne Compton polarimeter for X-rays in the $\sim$15-80 keV range. Using an X-ray mirror with a 12 m focal length for collecting photons onto a beryllium scattering rod surrounded by CZT detectors, a minimum-detectable polarization as low as $\sim$3% is expected during a 24-hour on-target observation of a 1 Crab source at 45$^{\circ}$ elevation. Systematic effects alter the reconstructed polarization as the mirror focal spot moves across the beryllium scatterer, due to pointing offsets, mechanical misalignment or deformation of the carbon-fiber truss supporting the mirror and the polarimeter. Unaddressed, this can give rise to a spurious polarization signal for an unpolarized flux, or a change in reconstructed polarization fraction and angle for a polarized flux. Using bench-marked Monte-Carlo simulations and an accurate mirror point-spread function characterized at synchrotron beam-lines, systematic effects are quantified, and mitigation strategies discussed. By recalculating the scattering site for a shifted beam, systematic errors can be reduced from several tens of percent to the few-percent level for any shift within the scattering element. The treatment of these systematic effects will be important for any polarimetric instrument where a focused X-ray beam is impinging on a scattering element surrounded by counting detectors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.15229v1-abstract-full').style.display = 'none'; document.getElementById('2402.15229v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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 Astroparticle Physics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astropart. Phys. 158 (2024) 102944 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.14191">arXiv:2311.14191</a> <span> [<a href="https://arxiv.org/pdf/2311.14191">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</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/10.3847/PSJ/acaf78">10.3847/PSJ/acaf78 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The enigmatic abundance of atomic hydrogen in Saturn's upper atmosphere </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ben-Jaffel%2C+L">Lotfi Ben-Jaffel</a>, <a href="/search/astro-ph?searchtype=author&query=Moses%2C+J">Julie Moses</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</a>, <a href="/search/astro-ph?searchtype=author&query=aye%2C+M">M-K. aye</a>, <a href="/search/astro-ph?searchtype=author&query=Bradley%2C+E+T">Eric T. Bradley</a>, <a href="/search/astro-ph?searchtype=author&query=Clarke%2C+J+T">John T. Clarke</a>, <a href="/search/astro-ph?searchtype=author&query=Holber%2C+J+B">Jay B. Holber</a>, <a href="/search/astro-ph?searchtype=author&query=Ballester%2C+G+E">Gilda E. Ballester</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="2311.14191v1-abstract-short" style="display: inline;"> A planet's Lyman-伪 (Ly伪) emission is sensitive to its thermospheric structure. Here, we report joint Hubble Space Telescope (HST) and Cassini cross-calibration observations of the Saturn Ly伪 emission made two weeks before the Cassini grand finale. To investigate the long-term Saturn Ly伪 airglow observed by different ultraviolet instruments, we cross-correlate their calibration, finding that while… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.14191v1-abstract-full').style.display = 'inline'; document.getElementById('2311.14191v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.14191v1-abstract-full" style="display: none;"> A planet's Lyman-伪 (Ly伪) emission is sensitive to its thermospheric structure. Here, we report joint Hubble Space Telescope (HST) and Cassini cross-calibration observations of the Saturn Ly伪 emission made two weeks before the Cassini grand finale. To investigate the long-term Saturn Ly伪 airglow observed by different ultraviolet instruments, we cross-correlate their calibration, finding that while the official Cassini/UVIS sensitivity should be lowered by ~75%, the Voyager 1/UVS sensitivities should be enhanced by ~20% at the Ly伪 channels. This comparison also allowed us to discover a permanent feature of the Saturn disk Ly伪 brightness that appears at all longitudes as a brightness excess (Ly伪 bulge) of ~30% (~12蟽) extending over the latitude range ~5-35N compared to the regions at equator and ~60N. This feature is confirmed by three distinct instruments between 1980 & 2017 in the Saturn north hemisphere. To analyze the Ly伪 observations, we use a radiation transfer (RT) model of resonant scattering of solar and interplanetary Ly伪 photons, and a latitude-dependent photochemistry model of the upper atmosphere constrained by occultation and remote-sensing observations. For each latitude, we show that the Ly伪 observations are sensitive to the temperature profile in the upper stratosphere and lower thermosphere, thus providing useful information in a region of the atmosphere that is difficult to probe by other means. In the Saturn Ly伪 bulge region, at latitudes between ~5 to ~35掳, the observed brightening and line broadening support seasonal effects, variation of the temperature vertical profile, and potential superthermal atoms that require confirmation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.14191v1-abstract-full').style.display = 'none'; document.getElementById('2311.14191v1-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, 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">Published in Planetary Science Journal. Added reference to grants</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Planet. Sci. J. 4 54 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.04782">arXiv:2311.04782</a> <span> [<a href="https://arxiv.org/pdf/2311.04782">pdf</a>, <a href="https://arxiv.org/format/2311.04782">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> </div> <p class="title is-5 mathjax"> The High Energy X-ray Probe (HEX-P): Probing Accretion onto Stellar Mass Black Holes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Connors%2C+R">Riley Connors</a>, <a href="/search/astro-ph?searchtype=author&query=Tomsick%2C+J">John Tomsick</a>, <a href="/search/astro-ph?searchtype=author&query=Draghis%2C+P">Paul Draghis</a>, <a href="/search/astro-ph?searchtype=author&query=Coughenour%2C+B">Benjamin Coughenour</a>, <a href="/search/astro-ph?searchtype=author&query=Shaw%2C+A">Aarran Shaw</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+J">Javier Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Walton%2C+D">Dominic Walton</a>, <a href="/search/astro-ph?searchtype=author&query=Madsen%2C+K">Kristin Madsen</a>, <a href="/search/astro-ph?searchtype=author&query=Stern%2C+D">Daniel Stern</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+N+C">Nicole Cavero Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Dauser%2C+T">Thomas Dauser</a>, <a href="/search/astro-ph?searchtype=author&query=Del+Santo%2C+M">Melania Del Santo</a>, <a href="/search/astro-ph?searchtype=author&query=Jiang%2C+J">Jiachen Jiang</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">Henric Krawczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+H">Honghui Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Neilsen%2C+J">Joseph Neilsen</a>, <a href="/search/astro-ph?searchtype=author&query=Nowak%2C+M">Michael Nowak</a>, <a href="/search/astro-ph?searchtype=author&query=Pike%2C+S">Sean Pike</a>, <a href="/search/astro-ph?searchtype=author&query=Santangelo%2C+A">Andrea Santangelo</a>, <a href="/search/astro-ph?searchtype=author&query=Sridhar%2C+N">Navin Sridhar</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A">Andrew West</a>, <a href="/search/astro-ph?searchtype=author&query=Wilms%2C+J">Joern Wilms</a>, <a href="/search/astro-ph?searchtype=author&query=Team%2C+t+H">the HEX-P Team</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="2311.04782v1-abstract-short" style="display: inline;"> Accretion is a universal astrophysical process that plays a key role in cosmic history, from the epoch of reionization to galaxy and stellar formation and evolution. Accreting stellar-mass black holes in X-ray binaries are one of the best laboratories to study the accretion process and probe strong gravity -- and most importantly, to measure the angular momentum, or spin, of black holes, and its r… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04782v1-abstract-full').style.display = 'inline'; document.getElementById('2311.04782v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.04782v1-abstract-full" style="display: none;"> Accretion is a universal astrophysical process that plays a key role in cosmic history, from the epoch of reionization to galaxy and stellar formation and evolution. Accreting stellar-mass black holes in X-ray binaries are one of the best laboratories to study the accretion process and probe strong gravity -- and most importantly, to measure the angular momentum, or spin, of black holes, and its role as a powering mechanism for relativistic astrophysical phenomena. Comprehensive characterization of the disk-corona system of accreting black holes, and their co-evolution, is fundamental to measurements of black hole spin. Here, we use simulated data to demonstrate how key unanswered questions in the study of accreting stellar-mass black holes will be addressed by the {\it High Energy X-ray Probe} (\hexp). \hexp\ is a probe-class mission concept that will combine high spatial resolution X-ray imaging and broad spectral coverage ($0.2\mbox{--}80$keV) with a sensitivity superior to current facilities (including \xmm\ and \nustar) to enable revolutionary new insights into a variety of important astrophysical problems. We illustrate the capability of \hexp\ to: 1) measure the evolving structures of black hole binary accretion flows down to low ($\lesssim0.1\%$) Eddington-scaled luminosities via detailed X-ray reflection spectroscopy; 2) provide unprecedented spectral observations of the coronal plasma, probing its elusive geometry and energetics; 3) perform detailed broadband studies of stellar mass black holes in nearby galaxies, thus expanding the repertoire of sources we can use to study accretion physics and determine the fundamental nature of black holes; and 4) act as a complementary observatory to a range of future ground and space-based astronomical observatories, thus providing key spectral measurements of the multi-component emission from the inner accretion flows of BH-XRBs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04782v1-abstract-full').style.display = 'none'; document.getElementById('2311.04782v1-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, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.05687">arXiv:2305.05687</a> <span> [<a href="https://arxiv.org/pdf/2305.05687">pdf</a>, <a href="https://arxiv.org/format/2305.05687">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/accc89">10.3847/1538-4357/accc89 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coronal Heating as Determined by the Solar Flare Frequency Distribution Obtained by Aggregating Case Studies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mason%2C+J+P">James Paul Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Werth%2C+A">Alexandra Werth</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+C+G">Colin G. West</a>, <a href="/search/astro-ph?searchtype=author&query=Youngblood%2C+A+A">Allison A. Youngblood</a>, <a href="/search/astro-ph?searchtype=author&query=Woodraska%2C+D+L">Donald L. Woodraska</a>, <a href="/search/astro-ph?searchtype=author&query=Peck%2C+C">Courtney Peck</a>, <a href="/search/astro-ph?searchtype=author&query=Lacjak%2C+K">Kevin Lacjak</a>, <a href="/search/astro-ph?searchtype=author&query=Frick%2C+F+G">Florian G. Frick</a>, <a href="/search/astro-ph?searchtype=author&query=Gabir%2C+M">Moutamen Gabir</a>, <a href="/search/astro-ph?searchtype=author&query=Alsinan%2C+R+A">Reema A. Alsinan</a>, <a href="/search/astro-ph?searchtype=author&query=Jacobsen%2C+T">Thomas Jacobsen</a>, <a href="/search/astro-ph?searchtype=author&query=Alrubaie%2C+M">Mohammad Alrubaie</a>, <a href="/search/astro-ph?searchtype=author&query=Chizmar%2C+K+M">Kayla M. Chizmar</a>, <a href="/search/astro-ph?searchtype=author&query=Lau%2C+B+P">Benjamin P. Lau</a>, <a href="/search/astro-ph?searchtype=author&query=Dominguez%2C+L+M">Lizbeth Montoya Dominguez</a>, <a href="/search/astro-ph?searchtype=author&query=Price%2C+D">David Price</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+D+R">Dylan R. Butler</a>, <a href="/search/astro-ph?searchtype=author&query=Biron%2C+C+J">Connor J. Biron</a>, <a href="/search/astro-ph?searchtype=author&query=Feoktistov%2C+N">Nikita Feoktistov</a>, <a href="/search/astro-ph?searchtype=author&query=Dewey%2C+K">Kai Dewey</a>, <a href="/search/astro-ph?searchtype=author&query=Loomis%2C+N+E">N. E. Loomis</a>, <a href="/search/astro-ph?searchtype=author&query=Bodzianowski%2C+M">Michal Bodzianowski</a>, <a href="/search/astro-ph?searchtype=author&query=Kuybus%2C+C">Connor Kuybus</a>, <a href="/search/astro-ph?searchtype=author&query=Dietrick%2C+H">Henry Dietrick</a>, <a href="/search/astro-ph?searchtype=author&query=Wolfe%2C+A+M">Aubrey M. Wolfe</a> , et al. (977 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2305.05687v1-abstract-short" style="display: inline;"> Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counter-intuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.05687v1-abstract-full').style.display = 'inline'; document.getElementById('2305.05687v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.05687v1-abstract-full" style="display: none;"> Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counter-intuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfv茅n waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold, $伪=2$ as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed $>$600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: pre-flare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine that $伪= 1.63 \pm 0.03$. This is below the critical threshold, suggesting that Alfv茅n waves are an important driver of coronal heating. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.05687v1-abstract-full').style.display = 'none'; document.getElementById('2305.05687v1-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 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">1,002 authors, 14 pages, 4 figures, 3 tables, published by The Astrophysical Journal on 2023-05-09, volume 948, page 71</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.12752">arXiv:2304.12752</a> <span> [<a href="https://arxiv.org/pdf/2304.12752">pdf</a>, <a href="https://arxiv.org/format/2304.12752">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/ad226e">10.3847/1538-4357/ad226e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> X-ray Polarization of the Black Hole X-ray Binary 4U 1630-47 Challenges Standard Thin Accretion Disk Scenario </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ratheesh%2C+A">Ajay Ratheesh</a>, <a href="/search/astro-ph?searchtype=author&query=Dov%C4%8Diak%2C+M">Michal Dov膷iak</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">Henric Krawczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Podgorn%C3%BD%2C+J">Jakub Podgorn媒</a>, <a href="/search/astro-ph?searchtype=author&query=Marra%2C+L">Lorenzo Marra</a>, <a href="/search/astro-ph?searchtype=author&query=Veledina%2C+A">Alexandra Veledina</a>, <a href="/search/astro-ph?searchtype=author&query=Suleimanov%2C+V">Valery Suleimanov</a>, <a href="/search/astro-ph?searchtype=author&query=Cavero%2C+N+R">Nicole Rodriguez Cavero</a>, <a href="/search/astro-ph?searchtype=author&query=Steiner%2C+J">James Steiner</a>, <a href="/search/astro-ph?searchtype=author&query=Svoboda%2C+J">Jiri Svoboda</a>, <a href="/search/astro-ph?searchtype=author&query=Marinucci%2C+A">Andrea Marinucci</a>, <a href="/search/astro-ph?searchtype=author&query=Bianchi%2C+S">Stefano Bianchi</a>, <a href="/search/astro-ph?searchtype=author&query=Negro%2C+M">Michela Negro</a>, <a href="/search/astro-ph?searchtype=author&query=Matt%2C+G">Giorgio Matt</a>, <a href="/search/astro-ph?searchtype=author&query=Tombesi%2C+F">Francesco Tombesi</a>, <a href="/search/astro-ph?searchtype=author&query=Poutanen%2C+J">Juri Poutanen</a>, <a href="/search/astro-ph?searchtype=author&query=Ingram%2C+A">Adam Ingram</a>, <a href="/search/astro-ph?searchtype=author&query=Taverna%2C+R">Roberto Taverna</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A">Andrew West</a>, <a href="/search/astro-ph?searchtype=author&query=Karas%2C+V">Vladimir Karas</a>, <a href="/search/astro-ph?searchtype=author&query=Ursini%2C+F">Francesco Ursini</a>, <a href="/search/astro-ph?searchtype=author&query=Soffitta%2C+P">Paolo Soffitta</a>, <a href="/search/astro-ph?searchtype=author&query=Capitanio%2C+F">Fiamma Capitanio</a>, <a href="/search/astro-ph?searchtype=author&query=Viscolo%2C+D">Domenico Viscolo</a>, <a href="/search/astro-ph?searchtype=author&query=Manfreda%2C+A">Alberto Manfreda</a> , et al. (90 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2304.12752v2-abstract-short" style="display: inline;"> Large energy-dependent X-ray polarization degree is detected by the Imaging X-ray Polarimetry Explorer ({IXPE}) in the high-soft emission state of the black hole X-ray binary 4U 1630--47. The highly significant detection (at $\approx50蟽$ confidence level) of an unexpectedly high polarization, rising from $\sim6\%$ at $2$ keV to $\sim10\%$ at $8$ keV, cannot be easily reconciled with standard model… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.12752v2-abstract-full').style.display = 'inline'; document.getElementById('2304.12752v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.12752v2-abstract-full" style="display: none;"> Large energy-dependent X-ray polarization degree is detected by the Imaging X-ray Polarimetry Explorer ({IXPE}) in the high-soft emission state of the black hole X-ray binary 4U 1630--47. The highly significant detection (at $\approx50蟽$ confidence level) of an unexpectedly high polarization, rising from $\sim6\%$ at $2$ keV to $\sim10\%$ at $8$ keV, cannot be easily reconciled with standard models of thin accretion discs. In this work we compare the predictions of different theoretical models with the {IXPE} data and conclude that the observed polarization properties are compatible with a scenario in which matter accretes onto the black hole through a thin disc, covered by a partially-ionized atmosphere flowing away at mildly relativistic velocities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.12752v2-abstract-full').style.display = 'none'; document.getElementById('2304.12752v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 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">Published in ApJ (https://doi.org/10.3847/1538-4357/ad226e)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2024 ApJ 964 77 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.04139">arXiv:2212.04139</a> <span> [<a href="https://arxiv.org/pdf/2212.04139">pdf</a>, <a href="https://arxiv.org/format/2212.04139">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.2022.167975">10.1016/j.nima.2022.167975 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The design and performance of the XL-Calibur anticoincidence shield </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Iyer%2C+N+K">N. K. Iyer</a>, <a href="/search/astro-ph?searchtype=author&query=Kiss%2C+M">M. Kiss</a>, <a href="/search/astro-ph?searchtype=author&query=Pearce%2C+M">M. Pearce</a>, <a href="/search/astro-ph?searchtype=author&query=Stana%2C+T+-">T. -A. Stana</a>, <a href="/search/astro-ph?searchtype=author&query=Awaki%2C+H">H. Awaki</a>, <a href="/search/astro-ph?searchtype=author&query=Bose%2C+R+G">R. G. Bose</a>, <a href="/search/astro-ph?searchtype=author&query=Dasgupta%2C+A">A. Dasgupta</a>, <a href="/search/astro-ph?searchtype=author&query=De+Geronimo%2C+G">G. De Geronimo</a>, <a href="/search/astro-ph?searchtype=author&query=Gau%2C+E">E. Gau</a>, <a href="/search/astro-ph?searchtype=author&query=Hakamata%2C+T">T. Hakamata</a>, <a href="/search/astro-ph?searchtype=author&query=Ishida%2C+M">M. Ishida</a>, <a href="/search/astro-ph?searchtype=author&query=Ishiwata%2C+K">K. Ishiwata</a>, <a href="/search/astro-ph?searchtype=author&query=Kamogawa%2C+W">W. Kamogawa</a>, <a href="/search/astro-ph?searchtype=author&query=Kislat%2C+F">F. Kislat</a>, <a href="/search/astro-ph?searchtype=author&query=Kitaguchi%2C+T">T. Kitaguchi</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">H. Krawczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Lisalda%2C+L">L. Lisalda</a>, <a href="/search/astro-ph?searchtype=author&query=Maeda%2C+Y">Y. Maeda</a>, <a href="/search/astro-ph?searchtype=author&query=Matsumoto%2C+H">H. Matsumoto</a>, <a href="/search/astro-ph?searchtype=author&query=Miyamoto%2C+A">A. Miyamoto</a>, <a href="/search/astro-ph?searchtype=author&query=Miyazawa%2C+T">T. Miyazawa</a>, <a href="/search/astro-ph?searchtype=author&query=Mizuno%2C+T">T. Mizuno</a>, <a href="/search/astro-ph?searchtype=author&query=Rauch%2C+B+F">B. F. Rauch</a>, <a href="/search/astro-ph?searchtype=author&query=Cavero%2C+N+R">N. Rodriguez Cavero</a>, <a href="/search/astro-ph?searchtype=author&query=Sakamoto%2C+N">N. Sakamoto</a> , et al. (9 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2212.04139v1-abstract-short" style="display: inline;"> The XL-Calibur balloon-borne hard X-ray polarimetry mission comprises a Compton-scattering polarimeter placed at the focal point of an X-ray mirror. The polarimeter is housed within a BGO anticoincidence shield, which is needed to mitigate the considerable background radiation present at the observation altitude of ~40 km. This paper details the design, construction and testing of the anticoincide… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.04139v1-abstract-full').style.display = 'inline'; document.getElementById('2212.04139v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.04139v1-abstract-full" style="display: none;"> The XL-Calibur balloon-borne hard X-ray polarimetry mission comprises a Compton-scattering polarimeter placed at the focal point of an X-ray mirror. The polarimeter is housed within a BGO anticoincidence shield, which is needed to mitigate the considerable background radiation present at the observation altitude of ~40 km. This paper details the design, construction and testing of the anticoincidence shield, as well as the performance measured during the week-long maiden flight from Esrange Space Centre to the Canadian Northwest Territories in July 2022. The in-flight performance of the shield followed design expectations, with a veto threshold <100 keV and a measured background rate of ~0.5 Hz (20-40 keV). This is compatible with the scientific goals of the mission, where %-level minimum detectable polarisation is sought for a Hz-level source rate. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.04139v1-abstract-full').style.display = 'none'; document.getElementById('2212.04139v1-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 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to Nuclear Instruments and Methods A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nuclear Instruments and Methods A 1048 (2023) 167975 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.06450">arXiv:2211.06450</a> <span> [<a href="https://arxiv.org/pdf/2211.06450">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</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/10.3847/1538-4357/ac9b42">10.3847/1538-4357/ac9b42 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Spectropolarimetry as a Means to Address Cloud Composition and Habitability for a Cloudy Exoplanetary Atmosphere in the Habitable Zone </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Dumont%2C+P">Philip Dumont</a>, <a href="/search/astro-ph?searchtype=author&query=Hu%2C+R">Renyu Hu</a>, <a href="/search/astro-ph?searchtype=author&query=Natraj%2C+V">Vijay Natraj</a>, <a href="/search/astro-ph?searchtype=author&query=Breckinridge%2C+J">James Breckinridge</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+P">Pin Chen</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="2211.06450v1-abstract-short" style="display: inline;"> In our solar system, the densely cloud-covered atmosphere of Venus stands out as an example of how polarimetry can be used to gain information on cloud composition and particle mean radius. With current interest running high on discovering and characterizing extrasolar planets in the habitable zone where water exists in the liquid state, making use of spectropolarimetric measurements of directly-i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.06450v1-abstract-full').style.display = 'inline'; document.getElementById('2211.06450v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.06450v1-abstract-full" style="display: none;"> In our solar system, the densely cloud-covered atmosphere of Venus stands out as an example of how polarimetry can be used to gain information on cloud composition and particle mean radius. With current interest running high on discovering and characterizing extrasolar planets in the habitable zone where water exists in the liquid state, making use of spectropolarimetric measurements of directly-imaged exoplanets could provide key information unobtainable through other means. In principle, spectropolarimetric measurements can determine if acidity causes water activities in the clouds to be too low for life. To this end, we show that a spectropolarimeter measurement over the range 400 nm - 1000 nm would need to resolve linear polarization to a precision of about 1% or better for reflected starlight from an optically thick cloud-enshrouded exoplanet. We assess the likelihood of achieving this goal by simulating measurements from a notional spectropolarimeter as part of a starshade configuration for a large space telescope (a HabEx design, but for a 6 m diameter primary mirror). Our simulations include consideration of noise from a variety of sources. We provide guidance on limits that would need to be levied on instrumental polarization to address the science issues we discuss. For photon-limited noise, integration times would need to be of order one hour for a large radius (10 Earth radii) planet to more than 100 hours for smaller exoplanets depending on the star-planet separation, planet radius, phase angle and desired uncertainty. We discuss implications for surface chemistry and habitability. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.06450v1-abstract-full').style.display = 'none'; document.getElementById('2211.06450v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 November, 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">ApJ, accepted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.12658">arXiv:2208.12658</a> <span> [<a href="https://arxiv.org/pdf/2208.12658">pdf</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="Chemical Physics">physics.chem-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/10.3847/2041-8213/ac8cef">10.3847/2041-8213/ac8cef <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The gas-phase reaction of NH2 with formaldehyde (CH2O) is not a source of formamide (NH2CHO) in interstellar environments </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Douglas%2C+K+M">Kevin M. Douglas</a>, <a href="/search/astro-ph?searchtype=author&query=Lucas%2C+D">Daniel Lucas</a>, <a href="/search/astro-ph?searchtype=author&query=Walsh%2C+C">Catherine Walsh</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+N+A">Niclas A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Blitz%2C+M+A">Mark A. Blitz</a>, <a href="/search/astro-ph?searchtype=author&query=Heard%2C+D+E">Dwayne E. Heard</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="2208.12658v1-abstract-short" style="display: inline;"> The first experimental study of the low-temperature kinetics of the gas-phase reaction of NH2 with formaldehyde (CH2O) has been performed. This reaction has previously been suggested as a source of formamide (NH2CHO) in interstellar environments. A pulsed Laval nozzle equipped with laser-flash photolysis and laser-induced fluorescence spectroscopy was used to create and monitor the temporal decay… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.12658v1-abstract-full').style.display = 'inline'; document.getElementById('2208.12658v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.12658v1-abstract-full" style="display: none;"> The first experimental study of the low-temperature kinetics of the gas-phase reaction of NH2 with formaldehyde (CH2O) has been performed. This reaction has previously been suggested as a source of formamide (NH2CHO) in interstellar environments. A pulsed Laval nozzle equipped with laser-flash photolysis and laser-induced fluorescence spectroscopy was used to create and monitor the temporal decay of NH2 in the presence of CH2O. No loss of NH2 could be observed via reaction with CH2O and we place an upper-limit on the rate coefficient of <6x10-12 cm3 molecule-1 s-1 at 34K. Ab initio calculations of the potential energy surface were combined with RRKM calculations to predict a rate coefficient of 6.2x10-14 cm3 molecule-1 s-1 at 35K, consistent with the experimental results. The presence of a significant barrier, 18 kJ mol-1, for the formation of formamide as a product, means that only the H-abstraction channel producing NH3 + CHO, in which the transfer of an H-atom can occur by quantum mechanical tunnelling through a 23 kJ mol-1 barrier, is open at low temperatures. These results are in contrast with a recent theoretical study which suggested that the reaction could proceed without a barrier and was therefore a viable route to gas-phase formamide formation. The calculated rate coefficients were used in an astrochemical model which demonstrated that this reaction produces only negligible amounts of gas-phase formamide under interstellar and circumstellar conditions. The reaction of NH2 with CH2O is therefore not an important source of formamide at low temperatures in interstellar environments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.12658v1-abstract-full').style.display = 'none'; document.getElementById('2208.12658v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Manuscript, 14 pages, 4 figures. Supporting Information, 8 pages, 2 figures. Accepted for publication in The Astrophysical Journal Letters</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.14652">arXiv:2206.14652</a> <span> [<a href="https://arxiv.org/pdf/2206.14652">pdf</a>, <a href="https://arxiv.org/format/2206.14652">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </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.9.2.024006">10.1117/1.JATIS.9.2.024006 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The 511-CAM Mission: A Pointed 511 keV Gamma-Ray Telescope with a Focal Plane Detector Made of Stacked Transition Edge Sensor Microcalorimeter Arrays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Shirazi%2C+F">Farzane Shirazi</a>, <a href="/search/astro-ph?searchtype=author&query=Hossen%2C+M+A">Md. Arman Hossen</a>, <a href="/search/astro-ph?searchtype=author&query=Becker%2C+D">Daniel Becker</a>, <a href="/search/astro-ph?searchtype=author&query=Schmidt%2C+D">Daniel Schmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Swetz%2C+D">Daniel Swetz</a>, <a href="/search/astro-ph?searchtype=author&query=Bennett%2C+D">Douglas Bennett</a>, <a href="/search/astro-ph?searchtype=author&query=Braun%2C+D">Dana Braun</a>, <a href="/search/astro-ph?searchtype=author&query=Gau%2C+E">Ephraim Gau</a>, <a href="/search/astro-ph?searchtype=author&query=Kislat%2C+F">Fabian Kislat</a>, <a href="/search/astro-ph?searchtype=author&query=Gard%2C+J">Johnathon Gard</a>, <a href="/search/astro-ph?searchtype=author&query=Mates%2C+J">John Mates</a>, <a href="/search/astro-ph?searchtype=author&query=Weber%2C+J">Joel Weber</a>, <a href="/search/astro-ph?searchtype=author&query=Cavero%2C+N+R">Nicole Rodriguez Cavero</a>, <a href="/search/astro-ph?searchtype=author&query=Chun%2C+S">Sohee Chun</a>, <a href="/search/astro-ph?searchtype=author&query=Lisalda%2C+L">Lindsey Lisalda</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A">Andrew West</a>, <a href="/search/astro-ph?searchtype=author&query=Dev%2C+B">Bhupal Dev</a>, <a href="/search/astro-ph?searchtype=author&query=Ferrer%2C+F">Francesc Ferrer</a>, <a href="/search/astro-ph?searchtype=author&query=Bose%2C+R">Richard Bose</a>, <a href="/search/astro-ph?searchtype=author&query=Ullom%2C+J">Joel Ullom</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">Henric Krawczynski</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="2206.14652v3-abstract-short" style="display: inline;"> The 511 keV gamma-ray emission from the galactic center region may fully or partially originate from the annihilation of positrons from dark matter particles with electrons from the interstellar medium. Alternatively, the positrons could be created by astrophysical sources, involving exclusively standard model physics. We describe here a new concept for a 511 keV mission called 511-CAM (511 keV ga… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.14652v3-abstract-full').style.display = 'inline'; document.getElementById('2206.14652v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.14652v3-abstract-full" style="display: none;"> The 511 keV gamma-ray emission from the galactic center region may fully or partially originate from the annihilation of positrons from dark matter particles with electrons from the interstellar medium. Alternatively, the positrons could be created by astrophysical sources, involving exclusively standard model physics. We describe here a new concept for a 511 keV mission called 511-CAM (511 keV gamma-ray CAmera using Micro-calorimeters) that combines focusing gamma-ray optics with a stack of Transition Edge Sensor (TES) microcalorimeter arrays in the focal plane. The 511-CAM detector assembly has a projected 511 keV energy resolution of 390 eV Full Width Half Maximum (FWHM) or better, and improves by a factor of at least 11 on the performance of state-of-the-art Ge-based Compton telescopes. Combining this unprecedented energy resolution with sub-arcmin angular resolutions afforded by Laue lens or channeling optics could make substantial contributions to identifying the origin of the 511 keV emission by discovering and characterizing point sources and measuring line-of-sight velocities of the emitting plasmas. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.14652v3-abstract-full').style.display = 'none'; document.getElementById('2206.14652v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 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, 11 figures, 2 tables; revised manuscript that addressed the referee's comments</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of Astronomical Telescopes, Instruments, and Systems, Volume 9, id. 024006 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.09761">arXiv:2204.09761</a> <span> [<a href="https://arxiv.org/pdf/2204.09761">pdf</a>, <a href="https://arxiv.org/format/2204.09761">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.astropartphys.2022.102749">10.1016/j.astropartphys.2022.102749 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Performance of the X-Calibur Hard X-Ray Polarimetry Mission during its 2018/19 Long-Duration Balloon Flight </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abarr%2C+Q">Quincy Abarr</a>, <a href="/search/astro-ph?searchtype=author&query=Beheshtipour%2C+B">Banafsheh Beheshtipour</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">Matthias Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=Bose%2C+R">Richard Bose</a>, <a href="/search/astro-ph?searchtype=author&query=Braun%2C+D">Dana Braun</a>, <a href="/search/astro-ph?searchtype=author&query=de+Geronimo%2C+G">Gianluigi de Geronimo</a>, <a href="/search/astro-ph?searchtype=author&query=Dowkontt%2C+P">Paul Dowkontt</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">Manel Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Gadson%2C+T">Thomas Gadson</a>, <a href="/search/astro-ph?searchtype=author&query=Guarino%2C+V">Victor Guarino</a>, <a href="/search/astro-ph?searchtype=author&query=Heatwole%2C+S">Scott Heatwole</a>, <a href="/search/astro-ph?searchtype=author&query=Hossen%2C+M+A">Md. Arman Hossen</a>, <a href="/search/astro-ph?searchtype=author&query=Iyer%2C+N+K">Nirmal K. Iyer</a>, <a href="/search/astro-ph?searchtype=author&query=Kislat%2C+F">Fabian Kislat</a>, <a href="/search/astro-ph?searchtype=author&query=Kiss%2C+M">M贸zsi Kiss</a>, <a href="/search/astro-ph?searchtype=author&query=Kitaguchi%2C+T">Takao Kitaguchi</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">Henric Krawczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Lanzi%2C+R+J">R. James Lanzi</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+S">Shaorui Li</a>, <a href="/search/astro-ph?searchtype=author&query=Lisalda%2C+L">Lindsey Lisalda</a>, <a href="/search/astro-ph?searchtype=author&query=Okajima%2C+T">Takashi Okajima</a>, <a href="/search/astro-ph?searchtype=author&query=Pearce%2C+M">Mark Pearce</a>, <a href="/search/astro-ph?searchtype=author&query=Peterson%2C+Z">Zachary Peterson</a>, <a href="/search/astro-ph?searchtype=author&query=Press%2C+L">Logan Press</a>, <a href="/search/astro-ph?searchtype=author&query=Rauch%2C+B">Brian Rauch</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="2204.09761v1-abstract-short" style="display: inline;"> X-Calibur is a balloon-borne telescope that measures the polarization of high-energy X-rays in the 15--50keV energy range. The instrument makes use of the fact that X-rays scatter preferentially perpendicular to the polarization direction. A beryllium scattering element surrounded by pixellated CZT detectors is located at the focal point of the InFOC渭S hard X-ray mirror. The instrument was launche… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.09761v1-abstract-full').style.display = 'inline'; document.getElementById('2204.09761v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.09761v1-abstract-full" style="display: none;"> X-Calibur is a balloon-borne telescope that measures the polarization of high-energy X-rays in the 15--50keV energy range. The instrument makes use of the fact that X-rays scatter preferentially perpendicular to the polarization direction. A beryllium scattering element surrounded by pixellated CZT detectors is located at the focal point of the InFOC渭S hard X-ray mirror. The instrument was launched for a long-duration balloon (LDB) flight from McMurdo (Antarctica) on December 29, 2018, and obtained the first constraints of the hard X-ray polarization of an accretion-powered pulsar. Here, we describe the characterization and calibration of the instrument on the ground and its performance during the flight, as well as simulations of particle backgrounds and a comparison to measured rates. The pointing system and polarimeter achieved the excellent projected performance. The energy detection threshold for the anticoincidence system was found to be higher than expected and it exhibited unanticipated dead time. Both issues will be remedied for future flights. Overall, the mission performance was nominal, and results will inform the design of the follow-up mission XL-Calibur, which is scheduled to be launched in summer 2022. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.09761v1-abstract-full').style.display = 'none'; document.getElementById('2204.09761v1-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 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 31 figures, submitted to Astropart. Phys</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.10466">arXiv:2110.10466</a> <span> [<a href="https://arxiv.org/pdf/2110.10466">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s10686-021-09815-8">10.1007/s10686-021-09815-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Science goals and new mission concepts for future exploration of Titan's atmosphere geology and habitability: Titan POlar Scout/orbitEr and In situ lake lander and DrONe explorer (POSEIDON) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+S">S茅bastien Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Vinatier%2C+S">Sandrine Vinatier</a>, <a href="/search/astro-ph?searchtype=author&query=Cordier%2C+D">Daniel Cordier</a>, <a href="/search/astro-ph?searchtype=author&query=Tobie%2C+G">Gabriel Tobie</a>, <a href="/search/astro-ph?searchtype=author&query=Achterberg%2C+R+K">Richard K. Achterberg</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+C+M">Carrie M. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Badman%2C+S+V">Sarah V. Badman</a>, <a href="/search/astro-ph?searchtype=author&query=Barnes%2C+J+W">Jason W. Barnes</a>, <a href="/search/astro-ph?searchtype=author&query=Barth%2C+E+L">Erika L. Barth</a>, <a href="/search/astro-ph?searchtype=author&query=B%C3%A9zard%2C+B">Bruno B茅zard</a>, <a href="/search/astro-ph?searchtype=author&query=Carrasco%2C+N">Nathalie Carrasco</a>, <a href="/search/astro-ph?searchtype=author&query=Charnay%2C+B">Benjamin Charnay</a>, <a href="/search/astro-ph?searchtype=author&query=Clark%2C+R+N">Roger N. Clark</a>, <a href="/search/astro-ph?searchtype=author&query=Coll%2C+P">Patrice Coll</a>, <a href="/search/astro-ph?searchtype=author&query=Cornet%2C+T">Thomas Cornet</a>, <a href="/search/astro-ph?searchtype=author&query=Coustenis%2C+A">Athena Coustenis</a>, <a href="/search/astro-ph?searchtype=author&query=Couturier-Tamburelli%2C+I">Isabelle Couturier-Tamburelli</a>, <a href="/search/astro-ph?searchtype=author&query=Dobrijevic%2C+M">Michel Dobrijevic</a>, <a href="/search/astro-ph?searchtype=author&query=Flasar%2C+F+M">F. Michael Flasar</a>, <a href="/search/astro-ph?searchtype=author&query=de+Kok%2C+R">Remco de Kok</a>, <a href="/search/astro-ph?searchtype=author&query=Freissinet%2C+C">Caroline Freissinet</a>, <a href="/search/astro-ph?searchtype=author&query=Galand%2C+M">Marina Galand</a>, <a href="/search/astro-ph?searchtype=author&query=Gautier%2C+T">Thomas Gautier</a>, <a href="/search/astro-ph?searchtype=author&query=Geppert%2C+W+D">Wolf D. Geppert</a>, <a href="/search/astro-ph?searchtype=author&query=Griffith%2C+C+A">Caitlin A. Griffith</a> , et al. (39 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="2110.10466v1-abstract-short" style="display: inline;"> In response to ESA Voyage 2050 announcement of opportunity, we propose an ambitious L-class mission to explore one of the most exciting bodies in the Solar System, Saturn largest moon Titan. Titan, a "world with two oceans", is an organic-rich body with interior-surface-atmosphere interactions that are comparable in complexity to the Earth. Titan is also one of the few places in the Solar System w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.10466v1-abstract-full').style.display = 'inline'; document.getElementById('2110.10466v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.10466v1-abstract-full" style="display: none;"> In response to ESA Voyage 2050 announcement of opportunity, we propose an ambitious L-class mission to explore one of the most exciting bodies in the Solar System, Saturn largest moon Titan. Titan, a "world with two oceans", is an organic-rich body with interior-surface-atmosphere interactions that are comparable in complexity to the Earth. Titan is also one of the few places in the Solar System with habitability potential. Titan remarkable nature was only partly revealed by the Cassini-Huygens mission and still holds mysteries requiring a complete exploration using a variety of vehicles and instruments. The proposed mission concept POSEIDON (Titan POlar Scout/orbitEr and In situ lake lander DrONe explorer) would perform joint orbital and in situ investigations of Titan. It is designed to build on and exceed the scope and scientific/technological accomplishments of Cassini-Huygens, exploring Titan in ways that were not previously possible, in particular through full close-up and in situ coverage over long periods of time. In the proposed mission architecture, POSEIDON consists of two major elements: a spacecraft with a large set of instruments that would orbit Titan, preferably in a low-eccentricity polar orbit, and a suite of in situ investigation components, i.e. a lake lander, a "heavy" drone (possibly amphibious) and/or a fleet of mini-drones, dedicated to the exploration of the polar regions. The ideal arrival time at Titan would be slightly before the next northern Spring equinox (2039), as equinoxes are the most active periods to monitor still largely unknown atmospheric and surface seasonal changes. The exploration of Titan northern latitudes with an orbiter and in situ element(s) would be highly complementary with the upcoming NASA New Frontiers Dragonfly mission that will provide in situ exploration of Titan equatorial regions in the mid-2030s. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.10466v1-abstract-full').style.display = 'none'; document.getElementById('2110.10466v1-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 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">arXiv admin note: substantial text overlap with arXiv:1908.01374</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.05384">arXiv:2102.05384</a> <span> [<a href="https://arxiv.org/pdf/2102.05384">pdf</a>, <a href="https://arxiv.org/format/2102.05384">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</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/abcd3b">10.3847/1538-4357/abcd3b <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Haze seasonal variations of Titan's upper atmosphere during the Cassini Mission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Seignovert%2C+B">Beno卯t Seignovert</a>, <a href="/search/astro-ph?searchtype=author&query=Rannou%2C+P">Pascal Rannou</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Vinatier%2C+S">Sandrine Vinatier</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="2102.05384v1-abstract-short" style="display: inline;"> This study presents a 13 years survey of haze UV extinction profiles, monitoring the temporal evolution of the detached haze layer (DHL) in Titan's upper atmosphere (350-600 km). As reported by West et al. 2011 (GRL vol.38, L06204) at the equator, we show that the DHL is present at all latitudes below 55掳N during the northern winter (2004-2009). Then, it globally sunk and disappeared in 2012. No p… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.05384v1-abstract-full').style.display = 'inline'; document.getElementById('2102.05384v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.05384v1-abstract-full" style="display: none;"> This study presents a 13 years survey of haze UV extinction profiles, monitoring the temporal evolution of the detached haze layer (DHL) in Titan's upper atmosphere (350-600 km). As reported by West et al. 2011 (GRL vol.38, L06204) at the equator, we show that the DHL is present at all latitudes below 55掳N during the northern winter (2004-2009). Then, it globally sunk and disappeared in 2012. No permanent DHL was observed between 2012 and 2015. It's only in late-2015, that a new structure emerged from the Northern hemisphere and propagated to the equator. This new DHL is not as pronounced as in 2004 and is much more complex than the one observed earlier. In one specific sequence, in 2005, we were able to investigate the short time scale variability of the DHL and no major changes was observed. When both side of the limb were visible (dawn/dusk), we notice that the extinction of the DHL is slightly higher on the dawn side. Additionally, during a polar flyby in 2009, we observed the longitudinal variability of the DHL and spotted some local inhomogeneities. Finally, comparisons with UVIS stellar occultations and General Climate Models (GCMs) are both consistent with our findings. However, we noticed that the timing of the DHL main pattern predicted by the GMCs can be off by up to 30掳 in solar longitude. All these observations bring new perspectives on the seasonal cycle of Titan's upper atmosphere, the evolution of the DHL and its interaction with the dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.05384v1-abstract-full').style.display = 'none'; document.getElementById('2102.05384v1-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 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 907 36 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.09288">arXiv:2012.09288</a> <span> [<a href="https://arxiv.org/pdf/2012.09288">pdf</a>, <a href="https://arxiv.org/format/2012.09288">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> </div> <p class="title is-5 mathjax"> Saturn's Seasonal Atmosphere at Northern Summer Solstice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fletcher%2C+L+N">L. N. Fletcher</a>, <a href="/search/astro-ph?searchtype=author&query=Sromovsky%2C+L">L. Sromovsky</a>, <a href="/search/astro-ph?searchtype=author&query=Hue%2C+V">V. Hue</a>, <a href="/search/astro-ph?searchtype=author&query=Moses%2C+J+I">J. I. Moses</a>, <a href="/search/astro-ph?searchtype=author&query=Guerlet%2C+S">S. Guerlet</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">R. A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Koskinen%2C+T">T. Koskinen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2012.09288v3-abstract-short" style="display: inline;"> The incredible longevity of Cassini's orbital mission at Saturn has provided the most comprehensive exploration of a seasonal giant planet to date. This review explores Saturn's changing global temperatures, composition, and aerosol properties between northern spring and summer solstice (2015-2017), extending our previous review of Cassini's remote sensing investigations (2004-14, Fletcher et al.,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.09288v3-abstract-full').style.display = 'inline'; document.getElementById('2012.09288v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.09288v3-abstract-full" style="display: none;"> The incredible longevity of Cassini's orbital mission at Saturn has provided the most comprehensive exploration of a seasonal giant planet to date. This review explores Saturn's changing global temperatures, composition, and aerosol properties between northern spring and summer solstice (2015-2017), extending our previous review of Cassini's remote sensing investigations (2004-14, Fletcher et al., 2018) to the grand finale. The result is an unprecedented record of Saturn's climate that spans almost half a Saturnian year, which can be used to test the seasonal predictions of radiative climate models, neutral and ion photochemistry models, and atmospheric circulation models. Hemispheric asymmetries in tropospheric and stratospheric temperatures were observed to reverse from northern winter to northern summer; spatial distributions of hydrocarbons and para-hydrogen shifted in response to atmospheric dynamics (e.g., seasonally-reversing Hadley cells, polar stratospheric vortex formation, equatorial stratospheric oscillations, and inter-hemispheric transport); and upper tropospheric and stratospheric aerosols exhibited changes in optical thickness that modulated Saturn's visible colours (from blue hues to a golden appearance in the north near solstice), reflectivity, and near-infrared emission. Numerical simulations of radiative balance and photochemistry do a good job in reproducing the observed seasonal change and phase lags, but discrepancies between models and observations still persist, indicating a crucial role for atmospheric dynamics and the need to couple chemical and radiative schemes to the next generation of circulation models. With Cassini's demise, an extended study of Saturn's seasons, from northern summer to autumn, will require the capabilities of ground- and space-based observatories, as we eagerly await the next orbital explorer at Saturn. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.09288v3-abstract-full').style.display = 'none'; document.getElementById('2012.09288v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 December, 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">24 pages, 17 figures, accepted for publication by Cambridge University Press as part of a multi-volume work edited by Kevin Baines, Michael Flasar, Norbert Krupp, and Thomas Stallard, entitled "Cassini at Saturn: The Grand Finale." The copy of the Chapter, as displayed on this website, is a draft, pre-publication copy only</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.10608">arXiv:2010.10608</a> <span> [<a href="https://arxiv.org/pdf/2010.10608">pdf</a>, <a href="https://arxiv.org/format/2010.10608">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.astropartphys.2020.102529">10.1016/j.astropartphys.2020.102529 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> XL-Calibur -- a second-generation balloon-borne hard X-ray polarimetry mission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abarr%2C+Q">Q. Abarr</a>, <a href="/search/astro-ph?searchtype=author&query=Awaki%2C+H">H. Awaki</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=Bose%2C+R">R. Bose</a>, <a href="/search/astro-ph?searchtype=author&query=De+Geronimo%2C+G">G. De Geronimo</a>, <a href="/search/astro-ph?searchtype=author&query=Dowkontt%2C+P">P. Dowkontt</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Guarino%2C+V">V. Guarino</a>, <a href="/search/astro-ph?searchtype=author&query=Hattori%2C+K">K. Hattori</a>, <a href="/search/astro-ph?searchtype=author&query=Hayashida%2C+K">K. Hayashida</a>, <a href="/search/astro-ph?searchtype=author&query=Imazato%2C+F">F. Imazato</a>, <a href="/search/astro-ph?searchtype=author&query=Ishida%2C+M">M. Ishida</a>, <a href="/search/astro-ph?searchtype=author&query=Iyer%2C+N+K">N. K. Iyer</a>, <a href="/search/astro-ph?searchtype=author&query=Kislat%2C+F">F. Kislat</a>, <a href="/search/astro-ph?searchtype=author&query=Kiss%2C+M">M. Kiss</a>, <a href="/search/astro-ph?searchtype=author&query=Kitaguchi%2C+T">T. Kitaguchi</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">H. Krawczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Lisalda%2C+L">L. Lisalda</a>, <a href="/search/astro-ph?searchtype=author&query=Matake%2C+H">H. Matake</a>, <a href="/search/astro-ph?searchtype=author&query=Maeda%2C+Y">Y. Maeda</a>, <a href="/search/astro-ph?searchtype=author&query=Matsumoto%2C+H">H. Matsumoto</a>, <a href="/search/astro-ph?searchtype=author&query=Mineta%2C+T">T. Mineta</a>, <a href="/search/astro-ph?searchtype=author&query=Miyazawa%2C+T">T. Miyazawa</a>, <a href="/search/astro-ph?searchtype=author&query=Mizuno%2C+T">T. Mizuno</a>, <a href="/search/astro-ph?searchtype=author&query=Okajima%2C+T">T. Okajima</a> , et al. (16 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="2010.10608v1-abstract-short" style="display: inline;"> XL-Calibur is a hard X-ray (15-80 keV) polarimetry mission operating from a stabilised balloon-borne platform in the stratosphere. It builds on heritage from the X-Calibur mission, which observed the accreting neutron star GX 301-2 from Antarctica, between December 29th 2018 and January 1st 2019. The XL-Calibur design incorporates an X-ray mirror, which focusses X-rays onto a polarimeter comprisin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.10608v1-abstract-full').style.display = 'inline'; document.getElementById('2010.10608v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.10608v1-abstract-full" style="display: none;"> XL-Calibur is a hard X-ray (15-80 keV) polarimetry mission operating from a stabilised balloon-borne platform in the stratosphere. It builds on heritage from the X-Calibur mission, which observed the accreting neutron star GX 301-2 from Antarctica, between December 29th 2018 and January 1st 2019. The XL-Calibur design incorporates an X-ray mirror, which focusses X-rays onto a polarimeter comprising a beryllium rod surrounded by Cadmium Zinc Telluride (CZT) detectors. The polarimeter is housed in an anticoincidence shield to mitigate background from particles present in the stratosphere. The mirror and polarimeter-shield assembly are mounted at opposite ends of a 12 m long lightweight truss, which is pointed with arcsecond precision by WASP - the Wallops Arc Second Pointer. The XL-Calibur mission will achieve a substantially improved sensitivity over X-Calibur by using a larger effective area X-ray mirror, reducing background through thinner CZT detectors, and improved anticoincidence shielding. When observing a 1 Crab source for $t_{\rm day}$ days, the Minimum Detectable Polarisation (at 99% confidence level) is $\sim$2$\%\cdot t_{\rm day}^{-1/2}$. The energy resolution at 40 keV is $\sim$5.9 keV. The aim of this paper is to describe the design and performance of the XL-Calibur mission, as well as the foreseen science programme. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.10608v1-abstract-full').style.display = 'none'; document.getElementById('2010.10608v1-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 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">19 pages, 17 figures. Accepted for publication in Astroparticle Physics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.08985">arXiv:2009.08985</a> <span> [<a href="https://arxiv.org/pdf/2009.08985">pdf</a>, <a href="https://arxiv.org/format/2009.08985">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/abba2d">10.3847/1538-4357/abba2d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the X-ray Spectral Energy Distributions of Star-Forming Galaxies: the 0.3-30 keV Spectrum of the Low-Metallicity Starburst Galaxy VV 114 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Garofali%2C+K">Kristen Garofali</a>, <a href="/search/astro-ph?searchtype=author&query=Lehmer%2C+B+D">Bret D. Lehmer</a>, <a href="/search/astro-ph?searchtype=author&query=Basu-Zych%2C+A">Antara Basu-Zych</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+L+A">Lacey A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Wik%2C+D">Daniel Wik</a>, <a href="/search/astro-ph?searchtype=author&query=Yukita%2C+M">Mihoko Yukita</a>, <a href="/search/astro-ph?searchtype=author&query=Vulic%2C+N">Neven Vulic</a>, <a href="/search/astro-ph?searchtype=author&query=Ptak%2C+A">Andrew Ptak</a>, <a href="/search/astro-ph?searchtype=author&query=Hornschemeier%2C+A">Ann Hornschemeier</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="2009.08985v1-abstract-short" style="display: inline;"> Binary population synthesis combined with cosmological models suggest that X-ray emission from star-forming galaxies, consisting primarily of emission from X-ray binaries (XRBs) and the hot interstellar medium (ISM), could be an important, and perhaps dominant, source of heating of the intergalactic medium prior to the epoch of reionization. However, such models rely on empirical constraints for t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.08985v1-abstract-full').style.display = 'inline'; document.getElementById('2009.08985v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.08985v1-abstract-full" style="display: none;"> Binary population synthesis combined with cosmological models suggest that X-ray emission from star-forming galaxies, consisting primarily of emission from X-ray binaries (XRBs) and the hot interstellar medium (ISM), could be an important, and perhaps dominant, source of heating of the intergalactic medium prior to the epoch of reionization. However, such models rely on empirical constraints for the X-ray spectral energy distributions (SEDs) of star-forming galaxies, which are currently lacking for low-metallicity galaxies. Using a combination of Chandra, XMM-Newton, and NuSTAR observations, we present new constraints on the 0.3-30 keV SED of the low-metallicity starburst galaxy VV 114, which is known to host several ultra-luminous X-ray sources (ULXs) with luminosities above 10$^{40}$ erg s$^{-1}$. We use an archival Chandra observation of VV 114 to constrain the contributions to the X-ray SED from the major X-ray emitting components of the galaxy, and newly acquired, nearly simultaneous XMM-Newton and NuSTAR observations to extend the spectral model derived from Chandra to cover the 0.3-30 keV range. Using our best-fit galaxy-wide spectral model, we derive the 0.3-30 keV SED of VV 114, which we find is dominated by emission from the XRB population, and in particular ULXs, at energies > 1.5 keV, and which we find to have an elevated galaxy-integrated X-ray luminosity per unit star formation rate relative to higher-metallicity star-forming galaxies. We discuss our results in terms of the effect of metallicity on XRB populations and the hot ISM, and the importance of X-ray emission from star-forming galaxies in the high redshift Universe. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.08985v1-abstract-full').style.display = 'none'; document.getElementById('2009.08985v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 September, 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">ApJ accepted. 25 pages, 8 figures, 4 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.03581">arXiv:2001.03581</a> <span> [<a href="https://arxiv.org/pdf/2001.03581">pdf</a>, <a href="https://arxiv.org/format/2001.03581">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab672c">10.3847/1538-4357/ab672c <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observations of a GX 301-2 Apastron Flare with the X-Calibur Hard X-Ray Polarimeter Supported by NICER, the Swift XRT and BAT, and Fermi GBM </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abarr%2C+Q">Q. Abarr</a>, <a href="/search/astro-ph?searchtype=author&query=Baring%2C+M">M. Baring</a>, <a href="/search/astro-ph?searchtype=author&query=Beheshtipour%2C+B">B. Beheshtipour</a>, <a href="/search/astro-ph?searchtype=author&query=Beilicke%2C+M">M. Beilicke</a>, <a href="/search/astro-ph?searchtype=author&query=deGeronimo%2C+G">G. deGeronimo</a>, <a href="/search/astro-ph?searchtype=author&query=Dowkontt%2C+P">P. Dowkontt</a>, <a href="/search/astro-ph?searchtype=author&query=Errando%2C+M">M. Errando</a>, <a href="/search/astro-ph?searchtype=author&query=Guarino%2C+V">V. Guarino</a>, <a href="/search/astro-ph?searchtype=author&query=Iyer%2C+N">N. Iyer</a>, <a href="/search/astro-ph?searchtype=author&query=Kislat%2C+F">F. Kislat</a>, <a href="/search/astro-ph?searchtype=author&query=Kiss%2C+M">M. Kiss</a>, <a href="/search/astro-ph?searchtype=author&query=Kitaguchi%2C+T">T. Kitaguchi</a>, <a href="/search/astro-ph?searchtype=author&query=Krawczynski%2C+H">H. Krawczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Lanzi%2C+J">J. Lanzi</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+S">S. Li</a>, <a href="/search/astro-ph?searchtype=author&query=Lisalda%2C+L">L. Lisalda</a>, <a href="/search/astro-ph?searchtype=author&query=Okajima%2C+T">T. Okajima</a>, <a href="/search/astro-ph?searchtype=author&query=Pearce%2C+M">M. Pearce</a>, <a href="/search/astro-ph?searchtype=author&query=Press%2C+L">L. Press</a>, <a href="/search/astro-ph?searchtype=author&query=Rauch%2C+B">B. Rauch</a>, <a href="/search/astro-ph?searchtype=author&query=Stuchlik%2C+D">D. Stuchlik</a>, <a href="/search/astro-ph?searchtype=author&query=Takahashi%2C+H">H. Takahashi</a>, <a href="/search/astro-ph?searchtype=author&query=Tang%2C+J">J. Tang</a>, <a href="/search/astro-ph?searchtype=author&query=Uchida%2C+N">N. Uchida</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A">A. West</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="2001.03581v1-abstract-short" style="display: inline;"> The accretion-powered X-ray pulsar GX 301-2 was observed with the balloon-borne X-Calibur hard X-ray polarimeter during late December 2018, with contiguous observations by the NICER X-ray telescope, the Swift X-ray Telescope and Burst Alert Telescope, and the Fermi Gamma-ray Burst Monitor spanning several months. The observations detected the pulsar in a rare apastron flaring state coinciding with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.03581v1-abstract-full').style.display = 'inline'; document.getElementById('2001.03581v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.03581v1-abstract-full" style="display: none;"> The accretion-powered X-ray pulsar GX 301-2 was observed with the balloon-borne X-Calibur hard X-ray polarimeter during late December 2018, with contiguous observations by the NICER X-ray telescope, the Swift X-ray Telescope and Burst Alert Telescope, and the Fermi Gamma-ray Burst Monitor spanning several months. The observations detected the pulsar in a rare apastron flaring state coinciding with a significant spin-up of the pulsar discovered with the Fermi GBM. The X-Calibur, NICER, and Swift observations reveal a pulse profile strongly dominated by one main peak, and the NICER and Swift data show strong variation of the profile from pulse to pulse. The X-Calibur observations constrain for the first time the linear polarization of the 15-35 keV emission from a highly magnetized accreting neutron star, indicating a polarization degree of (27+38-27)% (90% confidence limit) averaged over all pulse phases. We discuss the spin-up and the X-ray spectral and polarimetric results in the context of theoretical predictions. We conclude with a discussion of the scientific potential of future observations of highly magnetized neutron stars with the more sensitive follow-up mission XL-Calibur. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.03581v1-abstract-full').style.display = 'none'; document.getElementById('2001.03581v1-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 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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 the Astrophysical Journal. 20 pages, 19 figures, 4 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.07996">arXiv:1910.07996</a> <span> [<a href="https://arxiv.org/pdf/1910.07996">pdf</a>, <a href="https://arxiv.org/format/1910.07996">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/ab480e">10.3847/1538-4357/ab480e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measurements of Low Temperature Rate Coefficients for the Reaction of CH with CH$_{2}$O and Application to Dark Cloud and AGB Stellar Wind Models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=West%2C+N+A">Niclas A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Millar%2C+T+J">Tom J. Millar</a>, <a href="/search/astro-ph?searchtype=author&query=Van+de+Sande%2C+M">Marie Van de Sande</a>, <a href="/search/astro-ph?searchtype=author&query=Rutter%2C+E">Edward Rutter</a>, <a href="/search/astro-ph?searchtype=author&query=Blitz%2C+M+A">Mark A. Blitz</a>, <a href="/search/astro-ph?searchtype=author&query=Decin%2C+L">Leen Decin</a>, <a href="/search/astro-ph?searchtype=author&query=Heard%2C+D+E">Dwayne E. Heard</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="1910.07996v1-abstract-short" style="display: inline;"> Rate coefficients have been measured for the reaction of CH radicals with formaldehyde, CH$_{2}$O, over the temperature range 31 - 133 K using a pulsed Laval nozzle apparatus combined with pulsed laser photolysis and laser induced fluorescence spectroscopy. The rate coefficients are very large and display a distinct decrease with decreasing temperature below 70 K, although classical collision rate… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.07996v1-abstract-full').style.display = 'inline'; document.getElementById('1910.07996v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.07996v1-abstract-full" style="display: none;"> Rate coefficients have been measured for the reaction of CH radicals with formaldehyde, CH$_{2}$O, over the temperature range 31 - 133 K using a pulsed Laval nozzle apparatus combined with pulsed laser photolysis and laser induced fluorescence spectroscopy. The rate coefficients are very large and display a distinct decrease with decreasing temperature below 70 K, although classical collision rate theory fails to reproduce this temperature dependence. The measured rate coefficients have been parameterized and used as input for astrochemical models for both dark cloud and AGB stellar outflow scenarios. The models predict a distinct change (up to a factor of two) in the abundance of ketene, H$_{2}$CCO, which is the major expected molecular product of the CH + CH$_{2}$O reaction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.07996v1-abstract-full').style.display = 'none'; document.getElementById('1910.07996v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 9 Figures, 5 Tables, Accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.06816">arXiv:1903.06816</a> <span> [<a href="https://arxiv.org/pdf/1903.06816">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> </div> <p class="title is-5 mathjax"> On the Use of Planetary Science Data for Studying Extrasolar Planets </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Crichton%2C+D+J">Daniel J. Crichton</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+J+S">J. Steve Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=Roudier%2C+G">Gael Roudier</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Jewell%2C+J">Jeffrey Jewell</a>, <a href="/search/astro-ph?searchtype=author&query=Bryden%2C+G">Geoffrey Bryden</a>, <a href="/search/astro-ph?searchtype=author&query=Swain%2C+M">Mark Swain</a>, <a href="/search/astro-ph?searchtype=author&query=Lazio%2C+T+J+W">T. Joseph W. Lazio</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1903.06816v1-abstract-short" style="display: inline;"> There is an opportunity to advance both solar system and extrasolar planetary studies that does not require the construction of new telescopes or new missions but better use and access to inter-disciplinary data sets. This approach leverages significant investment from NASA and international space agencies in exploring this solar system and using those discoveries as "ground truth" for the study o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.06816v1-abstract-full').style.display = 'inline'; document.getElementById('1903.06816v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.06816v1-abstract-full" style="display: none;"> There is an opportunity to advance both solar system and extrasolar planetary studies that does not require the construction of new telescopes or new missions but better use and access to inter-disciplinary data sets. This approach leverages significant investment from NASA and international space agencies in exploring this solar system and using those discoveries as "ground truth" for the study of extrasolar planets. This white paper illustrates the potential, using phase curves and atmospheric modeling as specific examples. A key advance required to realize this potential is to enable seamless discovery and access within and between planetary science and astronomical data sets. Further, seamless data discovery and access also expands the availability of science, allowing researchers and students at a variety of institutions, equipped only with Internet access and a decent computer to conduct cutting-edge research. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.06816v1-abstract-full').style.display = 'none'; document.getElementById('1903.06816v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Science white paper submitted to the Astro2020 Decadal Survey</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1810.11483">arXiv:1810.11483</a> <span> [<a href="https://arxiv.org/pdf/1810.11483">pdf</a>, <a href="https://arxiv.org/ps/1810.11483">ps</a>, <a href="https://arxiv.org/format/1810.11483">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/aaec6b">10.3847/1538-4357/aaec6b <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the Nature of the X-ray Emission from the Ultraluminous X-ray Source, M33 X-8: New Constraints from NuSTAR and XMM-Newton </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=West%2C+L+A">Lacey A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Lehmer%2C+B+D">Bret D. Lehmer</a>, <a href="/search/astro-ph?searchtype=author&query=Wik%2C+D">Daniel Wik</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+J">Jun Yang</a>, <a href="/search/astro-ph?searchtype=author&query=Walton%2C+D+J">Dominic J. Walton</a>, <a href="/search/astro-ph?searchtype=author&query=Antoniou%2C+V">Vallia Antoniou</a>, <a href="/search/astro-ph?searchtype=author&query=Haberl%2C+F">Frank Haberl</a>, <a href="/search/astro-ph?searchtype=author&query=Hornschemeier%2C+A">Ann Hornschemeier</a>, <a href="/search/astro-ph?searchtype=author&query=Maccarone%2C+T+J">Thomas J. Maccarone</a>, <a href="/search/astro-ph?searchtype=author&query=Plucinsky%2C+P+P">Paul P. Plucinsky</a>, <a href="/search/astro-ph?searchtype=author&query=Ptak%2C+A">Andrew Ptak</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+B+F">Benjamin F. Williams</a>, <a href="/search/astro-ph?searchtype=author&query=Vulic%2C+N">Neven Vulic</a>, <a href="/search/astro-ph?searchtype=author&query=Yukita%2C+M">Mihoko Yukita</a>, <a href="/search/astro-ph?searchtype=author&query=Zezas%2C+A">Andreas Zezas</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1810.11483v1-abstract-short" style="display: inline;"> We present nearly simultaneous NuSTAR and XMM-Newton observations of the nearby (832 kpc) ultraluminous X-ray source (ULX) M33 X-8. M33 X-8 has a 0.3-10 keV luminosity of LX ~ 1.4 x 10^39 erg/s, near the boundary of the "ultraluminous" classification, making it an important source for understanding the link between typical Galactic X-ray binaries and ULXs. Past studies have shown that the 0.3-10 k… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.11483v1-abstract-full').style.display = 'inline'; document.getElementById('1810.11483v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1810.11483v1-abstract-full" style="display: none;"> We present nearly simultaneous NuSTAR and XMM-Newton observations of the nearby (832 kpc) ultraluminous X-ray source (ULX) M33 X-8. M33 X-8 has a 0.3-10 keV luminosity of LX ~ 1.4 x 10^39 erg/s, near the boundary of the "ultraluminous" classification, making it an important source for understanding the link between typical Galactic X-ray binaries and ULXs. Past studies have shown that the 0.3-10 keV spectrum of X-8 can be characterized using an advection-dominated accretion disk model. We find that when fitting to our NuSTAR and XMM-Newton observations, an additional high-energy (>10 keV) Comptonization component is required, which allows us to rule out single advection-dominated disk and classical sub-Eddington models. With our new constraints, we analyze XMM-Newton data taken over the last 17 years to show that small (~30%) variations in the 0.3-10 keV flux of M33 X-8 result in spectral changes similar to those observed for other ULXs. The two most likely phenomenological scenarios suggested by the data are degenerate in terms of constraining the nature of the accreting compact object (i.e., black hole versus neutron star). We further present a search for pulsations using our suite of data; however, no clear pulsations are detected. Future observations designed to observe M33 X-8 at different flux levels across the full 0.3-30 keV range would significantly improve our constraints on the nature of this important source. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.11483v1-abstract-full').style.display = 'none'; document.getElementById('1810.11483v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in ApJ (15 pages, 4 tables, 6 figures)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1804.10842">arXiv:1804.10842</a> <span> [<a href="https://arxiv.org/pdf/1804.10842">pdf</a>, <a href="https://arxiv.org/format/1804.10842">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41550-018-0434-z">10.1038/s41550-018-0434-z <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The seasonal cycle of Titan's detached haze </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Seignovert%2C+B">Beno卯t Seignovert</a>, <a href="/search/astro-ph?searchtype=author&query=Rannou%2C+P">Pascal Rannou</a>, <a href="/search/astro-ph?searchtype=author&query=Dumont%2C+P">Philip Dumont</a>, <a href="/search/astro-ph?searchtype=author&query=Turtle%2C+E+P">Elizabeth P. Turtle</a>, <a href="/search/astro-ph?searchtype=author&query=Perry%2C+J">Jason Perry</a>, <a href="/search/astro-ph?searchtype=author&query=Roy%2C+M">Mou Roy</a>, <a href="/search/astro-ph?searchtype=author&query=Ovanessian%2C+A">Aida Ovanessian</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="1804.10842v1-abstract-short" style="display: inline;"> Titan's 'detached' haze, seen in Voyager images in 1980 and 1981 and monitored by the Cassini Imaging Science Subsystem (ISS), during the period 2004-2017, provides a measure of seasonal activity in Titan's mesosphere with observations over almost one half of Saturn's seasonal cycle. Here we report on retrieved haze extinction profiles that reveal a depleted layer that visually manifests as a thin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1804.10842v1-abstract-full').style.display = 'inline'; document.getElementById('1804.10842v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1804.10842v1-abstract-full" style="display: none;"> Titan's 'detached' haze, seen in Voyager images in 1980 and 1981 and monitored by the Cassini Imaging Science Subsystem (ISS), during the period 2004-2017, provides a measure of seasonal activity in Titan's mesosphere with observations over almost one half of Saturn's seasonal cycle. Here we report on retrieved haze extinction profiles that reveal a depleted layer that visually manifests as a thin layer detached from the main haze below. Our new measurements show the disappearance of the feature in 2012 and its reappearance in 2016, as well as details after the reappearance. These observations highlight the dynamical nature of the detached haze. The reappearance appears congruent but more complex than previously described by climate models. It occurs in two steps, first as haze reappearing at $450\pm20$ km and one year later at $510\pm20$ km. These new observations provide additional tight and valuable constraints about the underlying mechanisms, especially for Titan's mesosphere, that control Titan's haze cycle. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1804.10842v1-abstract-full').style.display = 'none'; document.getElementById('1804.10842v1-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, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Nature Astronomy, 2018</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1712.03964">arXiv:1712.03964</a> <span> [<a href="https://arxiv.org/pdf/1712.03964">pdf</a>, <a href="https://arxiv.org/format/1712.03964">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/aaa0cf">10.3847/1538-4357/aaa0cf <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> 2MASS J11151597+1937266: A Young, Dusty, Isolated, Planetary-Mass Object with a Potential Wide Stellar Companion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Theissen%2C+C+A">Christopher A. Theissen</a>, <a href="/search/astro-ph?searchtype=author&query=Burgasser%2C+A+J">Adam J. Burgasser</a>, <a href="/search/astro-ph?searchtype=author&query=Gagliuffi%2C+D+C+B">Daniella C. Bardalez Gagliuffi</a>, <a href="/search/astro-ph?searchtype=author&query=Hardegree-Ullman%2C+K+K">Kevin K. Hardegree-Ullman</a>, <a href="/search/astro-ph?searchtype=author&query=Gagn%C3%A9%2C+J">Jonathan Gagn茅</a>, <a href="/search/astro-ph?searchtype=author&query=Schmidt%2C+S+J">Sarah J. Schmidt</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</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="1712.03964v2-abstract-short" style="display: inline;"> We present 2MASS J11151597+1937266, a recently identified low-surface gravity L dwarf, classified as an L2$纬$ based on Sloan Digital Sky Survey optical spectroscopy. We confirm this spectral type with near-infrared spectroscopy, which provides further evidence that 2MASS J11151597+1937266 is a low-surface gravity L dwarf. This object also shows significant excess mid-infrared flux, indicative of c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.03964v2-abstract-full').style.display = 'inline'; document.getElementById('1712.03964v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1712.03964v2-abstract-full" style="display: none;"> We present 2MASS J11151597+1937266, a recently identified low-surface gravity L dwarf, classified as an L2$纬$ based on Sloan Digital Sky Survey optical spectroscopy. We confirm this spectral type with near-infrared spectroscopy, which provides further evidence that 2MASS J11151597+1937266 is a low-surface gravity L dwarf. This object also shows significant excess mid-infrared flux, indicative of circumstellar material; and its strong H$伪$ emission (EW$_{\mathrm{H}伪}=560\pm82$ 脜) is an indicator of enhanced magnetic activity or weak accretion. Comparison of its spectral energy distribution to model photospheres yields an effective temperature of $1724^{+184}_{-38}$ K. We also provide a revised distance estimate of $37\pm6$ pc using a spectral type-luminosity relationship for low-surface gravity objects. The 3-dimensional galactic velocities and positions of 2MASS J11151597+1937266 do not match any known young association or moving group. Assuming a probable age in the range of 5-45 Myr, the model-dependent estimated mass of this object is between 7-21 $M_\mathrm{Jup}$, making it a potentially isolated planetary-mass object. We also identify a candidate co-moving, young stellar companion, 2MASS J11131089+2110086. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.03964v2-abstract-full').style.display = 'none'; document.getElementById('1712.03964v2-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 December, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 December, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">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/1709.02763">arXiv:1709.02763</a> <span> [<a href="https://arxiv.org/pdf/1709.02763">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> </div> <p class="title is-5 mathjax"> Solar system science with the Wide-Field InfraRed Survey Telescope (WFIRST) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Holler%2C+B+J">B. J. Holler</a>, <a href="/search/astro-ph?searchtype=author&query=Milam%2C+S+N">S. N. Milam</a>, <a href="/search/astro-ph?searchtype=author&query=Bauer%2C+J+M">J. M. Bauer</a>, <a href="/search/astro-ph?searchtype=author&query=Alcock%2C+C">C. Alcock</a>, <a href="/search/astro-ph?searchtype=author&query=Bannister%2C+M+T">M. T. Bannister</a>, <a href="/search/astro-ph?searchtype=author&query=Bjoraker%2C+G+L">G. L. Bjoraker</a>, <a href="/search/astro-ph?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/astro-ph?searchtype=author&query=Bosh%2C+A+S">A. S. Bosh</a>, <a href="/search/astro-ph?searchtype=author&query=Buie%2C+M+W">M. W. Buie</a>, <a href="/search/astro-ph?searchtype=author&query=Farnham%2C+T+L">T. L. Farnham</a>, <a href="/search/astro-ph?searchtype=author&query=Haghighipour%2C+N">N. Haghighipour</a>, <a href="/search/astro-ph?searchtype=author&query=Hardersen%2C+P+S">P. S. Hardersen</a>, <a href="/search/astro-ph?searchtype=author&query=Harris%2C+A+W">A. W. Harris</a>, <a href="/search/astro-ph?searchtype=author&query=Hirata%2C+C+M">C. M. Hirata</a>, <a href="/search/astro-ph?searchtype=author&query=Hsieh%2C+H+H">H. H. Hsieh</a>, <a href="/search/astro-ph?searchtype=author&query=Kelley%2C+M+S+P">M. S. P. Kelley</a>, <a href="/search/astro-ph?searchtype=author&query=Knight%2C+M+M">M. M. Knight</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+E+A">E. A. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Longobardo%2C+A">A. Longobardo</a>, <a href="/search/astro-ph?searchtype=author&query=Nixon%2C+C+A">C. A. Nixon</a>, <a href="/search/astro-ph?searchtype=author&query=Palomba%2C+E">E. Palomba</a>, <a href="/search/astro-ph?searchtype=author&query=Protopapa%2C+S">S. Protopapa</a>, <a href="/search/astro-ph?searchtype=author&query=Quick%2C+L+C">L. C. Quick</a>, <a href="/search/astro-ph?searchtype=author&query=Ragozzine%2C+D">D. Ragozzine</a>, <a href="/search/astro-ph?searchtype=author&query=Reddy%2C+V">V. Reddy</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="1709.02763v3-abstract-short" style="display: inline;"> We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field InfraRed Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43-2.0 $渭$m and will be a potential contemporary and eventual successor to JWST. Surveys of irregular satellites and minor bodies are wher… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1709.02763v3-abstract-full').style.display = 'inline'; document.getElementById('1709.02763v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1709.02763v3-abstract-full" style="display: none;"> We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field InfraRed Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43-2.0 $渭$m and will be a potential contemporary and eventual successor to JWST. Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg$^2$ field of view Wide Field Instrument (WFI). Potential ground-breaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the Inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper Belt Objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, LSST, JWST, and the proposed NEOCam mission are discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1709.02763v3-abstract-full').style.display = 'none'; document.getElementById('1709.02763v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 September, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">58 pages, 14 figures, 7 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1707.08576">arXiv:1707.08576</a> <span> [<a href="https://arxiv.org/pdf/1707.08576">pdf</a>, <a href="https://arxiv.org/format/1707.08576">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/10.3847/1538-3881/aa83b5">10.3847/1538-3881/aa83b5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Activity and Kinematics of White Dwarf-M Dwarf Binaries from the SUPERBLINK Proper Motion Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Skinner%2C+J+N">Julie N. Skinner</a>, <a href="/search/astro-ph?searchtype=author&query=Morgan%2C+D+P">Dylan P. Morgan</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Lepine%2C+S">Sebastien Lepine</a>, <a href="/search/astro-ph?searchtype=author&query=Thorstensen%2C+J+R">John R. Thorstensen</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="1707.08576v1-abstract-short" style="display: inline;"> We present an activity and kinematic analysis of high proper motion white dwarf-M dwarf binaries (WD+dMs) found in the SUPERBLINK survey, 178 of which are new identifications. To identify WD+dMs, we developed a UV-optical-IR color criterion and conducted a spectroscopic survey to confirm each candidate binary. For the newly identified systems, we fit the two components using model white dwarf spec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.08576v1-abstract-full').style.display = 'inline'; document.getElementById('1707.08576v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.08576v1-abstract-full" style="display: none;"> We present an activity and kinematic analysis of high proper motion white dwarf-M dwarf binaries (WD+dMs) found in the SUPERBLINK survey, 178 of which are new identifications. To identify WD+dMs, we developed a UV-optical-IR color criterion and conducted a spectroscopic survey to confirm each candidate binary. For the newly identified systems, we fit the two components using model white dwarf spectra and M dwarf template spectra to determine physical parameters. We use H$伪$ chromospheric emission to examine the magnetic activity of the M dwarf in each system, and investigate how its activity is affected by the presence of a white dwarf companion. We find that the fraction of WD+dM binaries with active M dwarfs is significantly higher than their single M dwarf counterparts at early and mid spectral types. We corroborate previous studies that find high activity fractions at both close and intermediate separations. At more distant separations the binary fraction appears to approach the activity fraction for single M dwarfs. Using derived radial velocities and the proper motions, we calculate 3D space velocities for the WD+dMs in SUPERBLINK. For the entire SUPERBLINK WD+dMs, we find a large vertical velocity dispersion, indicating a dynamically hotter population compared to high proper motion samples of single M dwarfs. We compare the kinematics for systems with active M dwarfs and those with inactive M dwarfs, and find signatures of asymmetric drift in the inactive sample, indicating that they are drawn from an older population. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.08576v1-abstract-full').style.display = 'none'; document.getElementById('1707.08576v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 7 figures, 4 tables, Accepted to The Astronomical 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/1704.07460">arXiv:1704.07460</a> <span> [<a href="https://arxiv.org/pdf/1704.07460">pdf</a>, <a href="https://arxiv.org/format/1704.07460">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41550-017-0114">10.1038/s41550-017-0114 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Titan brighter at twilight than in daylight </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mu%C3%B1oz%2C+A+G">Antonio Garc铆a Mu帽oz</a>, <a href="/search/astro-ph?searchtype=author&query=Lavvas%2C+P">Panayotis Lavvas</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</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="1704.07460v1-abstract-short" style="display: inline;"> Investigating the overall brightness of planets (and moons) provides insight into their envelopes and energy budgets [1, 2, 3, 4]. Titan phase curves (a representation of overall brightness vs. Sun-object-observer phase angle) have been published over a limited range of phase angles and spectral passbands [5, 6]. Such information has been key to the study of the stratification, microphysics and ag… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.07460v1-abstract-full').style.display = 'inline'; document.getElementById('1704.07460v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1704.07460v1-abstract-full" style="display: none;"> Investigating the overall brightness of planets (and moons) provides insight into their envelopes and energy budgets [1, 2, 3, 4]. Titan phase curves (a representation of overall brightness vs. Sun-object-observer phase angle) have been published over a limited range of phase angles and spectral passbands [5, 6]. Such information has been key to the study of the stratification, microphysics and aggregate nature of Titan's atmospheric haze [7, 8], and has complemented the spatially-resolved observations first showing that the haze scatters efficiently in the forward direction [7, 9]. Here we present Cassini Imaging Science Subsystem whole-disk brightness measurements of Titan from ultraviolet to near-infrared wavelengths. The observations reveal that Titan's twilight (loosely defined as the view when the phase angle 150deg) outshines its daylight at various wavelengths. From the match between measurements and models, we show that at even larger phase angles the back-illuminated moon will appear much brighter than when fully illuminated. This behavior is unique to Titan in our solar system, and is caused by its extended atmosphere and the efficient forward scattering of sunlight by its atmospheric haze. We infer a solar energy deposition rate (for a solar constant of 14.9 Wm-2) of (2.84+/-0.11)x10^14 W, consistent to within 1-2 standard deviations with Titan's time-varying thermal emission spanning 2007- 2013 [10, 11]. We propose that a forward scattering signature may also occur at large phase angles in the brightness of exoplanets with extended hazy atmospheres, and that this signature has valuable diagnostic potential for atmospheric characterization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.07460v1-abstract-full').style.display = 'none'; document.getElementById('1704.07460v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Pre-print of a manuscript published in Nature Astronomy 1, 0114 (2017) DOI: 10.1038/s41550-017-0114, http://www.nature.com/nastronomy</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Astronomy 1, 0114 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1704.00842">arXiv:1704.00842</a> <span> [<a href="https://arxiv.org/pdf/1704.00842">pdf</a>, <a href="https://arxiv.org/format/1704.00842">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</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.icarus.2017.03.026">10.1016/j.icarus.2017.03.026 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Aerosols optical properties in Titan's Detached Haze Layer before the equinox </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Seignovert%2C+B">Beno卯t Seignovert</a>, <a href="/search/astro-ph?searchtype=author&query=Rannou%2C+P">Pascal Rannou</a>, <a href="/search/astro-ph?searchtype=author&query=Lavvas%2C+P">Panayotis Lavvas</a>, <a href="/search/astro-ph?searchtype=author&query=Cours%2C+T">Thibaud Cours</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</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="1704.00842v1-abstract-short" style="display: inline;"> UV observations with Cassini ISS Narrow Angle Camera of Titan's detached haze is an excellent tool to probe its aerosols content without being affected by the gas or the multiple scattering. Unfortunately, its low extent in altitude requires a high resolution calibration and limits the number of images available in the Cassini dataset. However, we show that it is possible to extract on each profil… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.00842v1-abstract-full').style.display = 'inline'; document.getElementById('1704.00842v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1704.00842v1-abstract-full" style="display: none;"> UV observations with Cassini ISS Narrow Angle Camera of Titan's detached haze is an excellent tool to probe its aerosols content without being affected by the gas or the multiple scattering. Unfortunately, its low extent in altitude requires a high resolution calibration and limits the number of images available in the Cassini dataset. However, we show that it is possible to extract on each profile the local maximum of intensity of this layer and confirm its stability at $500 \pm 8$ km during the 2005-2007 period for all latitudes lower than 45$^\circ$N. Using the fractal aggregate scattering model of Tomasko et al. (2008) and a single scattering radiative transfer model, it is possible to derive the optical properties required to explain the observations made at different phase angles. Our results indicates that the aerosols have at least ten monomers of 60 nm radius, while the typical tangential column number density is about $2\cdot 10^{10}$ agg.m$^{-2}$. Moreover, we demonstrate that these properties are constant within the error bars in the southern hemisphere of Titan over the observed time period. In the northern hemisphere, the size of the aerosols tend to decrease relatively to the southern hemisphere and are associated with a higher tangential opacity. However, the lower number of observations available in this region due to the orbital constraints is a limiting factor in the accuracy of these results. Assuming a fixed homogeneous content we notice that the tangential opacity can fluctuate up to a factor 3 among the observations at the equator. These variations could be linked with short scale temporal and/or longitudinal events changing the local density of the layer. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.00842v1-abstract-full').style.display = 'none'; document.getElementById('1704.00842v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2017. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.08465">arXiv:1702.08465</a> <span> [<a href="https://arxiv.org/pdf/1702.08465">pdf</a>, <a href="https://arxiv.org/format/1702.08465">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="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-3881/aa6343">10.3847/1538-3881/aa6343 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Collisions of Terrestrial Worlds: The Occurrence of Extreme Mid-Infrared Excesses around Low-Mass Field Stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Theissen%2C+C">Christopher Theissen</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A">Andrew West</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="1702.08465v1-abstract-short" style="display: inline;"> We present the results of an investigation into the occurrence and properties (stellar age and mass trends) of low-mass field stars exhibiting extreme mid-infrared (MIR) excesses ($L_\mathrm{IR} / L_\ast \gtrsim 0.01$). Stars for the analysis were initially selected from the Motion Verified Red Stars (MoVeRS) catalog of photometric stars with SDSS, 2MASS, and $WISE$ photometry and significant prop… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.08465v1-abstract-full').style.display = 'inline'; document.getElementById('1702.08465v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.08465v1-abstract-full" style="display: none;"> We present the results of an investigation into the occurrence and properties (stellar age and mass trends) of low-mass field stars exhibiting extreme mid-infrared (MIR) excesses ($L_\mathrm{IR} / L_\ast \gtrsim 0.01$). Stars for the analysis were initially selected from the Motion Verified Red Stars (MoVeRS) catalog of photometric stars with SDSS, 2MASS, and $WISE$ photometry and significant proper motions. We identify 584 stars exhibiting extreme MIR excesses, selected based on an empirical relationship for main sequence $W1-W3$ colors. For a small subset of the sample, we show, using spectroscopic tracers of stellar age (H$伪$ and Li ${\rm{\small I}}$) and luminosity class, that the parent sample is likely comprised of field dwarfs ($\gtrsim$ 1 Gyr). We also develop the Low-mass Kinematics ($LoKi$) galactic model to estimate the completeness of the extreme MIR excess sample. Using Galactic height as a proxy for stellar age, the completeness corrected analysis indicates a distinct age dependence for field stars exhibiting extreme MIR excesses. We also find a trend with stellar mass (using $r-z$ color as a proxy). Our findings are consistent with the detected extreme MIR excesses originating from dust created in a short-lived collisional cascade ($\lesssim$ 100,000 years) during a giant impact between two large planetismals or terrestrial planets. These stars with extreme MIR excesses also provide support for planetary collisions being the dominant mechanism in creating the observed $Kepler$ dichotomy (the need for more than a single mode, typically two, to explain the variety of planetary system architectures $Kepler$ has observed), rather than different formation mechanisms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.08465v1-abstract-full').style.display = 'none'; document.getElementById('1702.08465v1-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 February, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">33 pages, 26 figures, 10 tables. Accepted for publication in AJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.06957">arXiv:1702.06957</a> <span> [<a href="https://arxiv.org/pdf/1702.06957">pdf</a>, <a href="https://arxiv.org/format/1702.06957">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> </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/aa656d">10.3847/1538-4365/aa656d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An empirical template library of stellar spectra for a wide range of spectral classes, luminosity classes, and metallicities using SDSS BOSS spectra </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kesseli%2C+A+Y">Aurora Y. Kesseli</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Veyette%2C+M">Mark Veyette</a>, <a href="/search/astro-ph?searchtype=author&query=Harrison%2C+B">Brandon Harrison</a>, <a href="/search/astro-ph?searchtype=author&query=Feldman%2C+D">Dan Feldman</a>, <a href="/search/astro-ph?searchtype=author&query=Bochanski%2C+J+J">John J. Bochanski</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="1702.06957v2-abstract-short" style="display: inline;"> We present a library of empirical stellar spectra created using spectra from the Sloan Digital Sky Survey's Baryon Oscillation Spectroscopic Survey (BOSS). The templates cover spectral types O5 through L3, are binned by metallicity from -2.0 dex through +1.0 dex and are separated into main sequence (dwarf) stars and giant stars. With recently developed M dwarf metallicity indicators, we are able t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.06957v2-abstract-full').style.display = 'inline'; document.getElementById('1702.06957v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.06957v2-abstract-full" style="display: none;"> We present a library of empirical stellar spectra created using spectra from the Sloan Digital Sky Survey's Baryon Oscillation Spectroscopic Survey (BOSS). The templates cover spectral types O5 through L3, are binned by metallicity from -2.0 dex through +1.0 dex and are separated into main sequence (dwarf) stars and giant stars. With recently developed M dwarf metallicity indicators, we are able to extend the metallicity bins down through the spectral subtype M8, making this the first empirical library with this degree of temperature \emph{and} metallicity coverage. The wavelength coverage for the templates is from 3650 Angstroms through 10200 Angstroms at a resolution better than R~2000. Using the templates, we identify trends in color space with metallicity and surface gravity, which will be useful for analyzing large data sets from upcoming missions like LSST. Along with the templates, we are releasing a code for automatically (and/or visually) identifying the spectral type and metallicity of a star. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.06957v2-abstract-full').style.display = 'none'; document.getElementById('1702.06957v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 February, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted to ApJS; updated links to template files and spectra, now include standard format fits files and SDSS binary table fits files</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1612.05252">arXiv:1612.05252</a> <span> [<a href="https://arxiv.org/pdf/1612.05252">pdf</a>, <a href="https://arxiv.org/format/1612.05252">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/10.3847/1538-3881/153/3/92">10.3847/1538-3881/153/3/92 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Late-Type Extension to MoVeRS (LaTE-MoVeRS): Proper motion verified low-mass stars and brown dwarfs from SDSS, 2MASS, and WISE </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Theissen%2C+C+A">Christopher A. Theissen</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Shippe%2C+G">Guillaume Shippe</a>, <a href="/search/astro-ph?searchtype=author&query=Burgasser%2C+A+J">Adam J. Burgasser</a>, <a href="/search/astro-ph?searchtype=author&query=Schmidt%2C+S+J">Sarah J. Schmidt</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="1612.05252v1-abstract-short" style="display: inline;"> We present the Late-Type Extension to the Motion Verified Red Stars (LaTE-MoVeRS) catalog, containing 46,463 photometric late-type ($>$ M5) dwarfs within the Sloan Digital Sky Survey (SDSS) footprint. Proper motions were computed for objects combining astrometry from the SDSS Data Release 12 (DR12), the Two-Micron All-Sky Survey (2MASS) Point Source Catalog (PSC), and the \emph{Wide-field Infrared… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.05252v1-abstract-full').style.display = 'inline'; document.getElementById('1612.05252v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1612.05252v1-abstract-full" style="display: none;"> We present the Late-Type Extension to the Motion Verified Red Stars (LaTE-MoVeRS) catalog, containing 46,463 photometric late-type ($>$ M5) dwarfs within the Sloan Digital Sky Survey (SDSS) footprint. Proper motions were computed for objects combining astrometry from the SDSS Data Release 12 (DR12), the Two-Micron All-Sky Survey (2MASS) Point Source Catalog (PSC), and the \emph{Wide-field Infrared Survey Explorer} (\emph{WISE}) AllWISE datasets. LaTE-MoVeRS objects were required to have significant proper motion ($渭_\mathrm{tot} \geqslant 2蟽_{渭_\mathrm{tot}}$). Using the LaTE-MoVeRS sample and \emph{Gaia} Data Release 1, we estimate \emph{Gaia} will be $\sim$64\% complete for very-low-mass objects ($>$ M5) in comparison to the combined SDSS+2MASS+\emph{WISE} dataset ($i < 21.3$). We computed photometric distances and estimated stellar effective temperatures for the LaTE-MoVeRS catalog. The majority of the dwarfs in the sample have distances $< 150$ pc and $T_\mathrm{eff} < 3000$ K. Thirteen objects were identified within LaTE-MoVeRS with estimated photometric distances within 25 pc that have not been previously identified as nearby objects. We also identified one new object with a large amount of excess mid-infrared flux that has not been previously identified (2MASS J11151597$+$1937266). This object appears to be an L2$纬$ at $\sim$50 pc showing spectroscopic signs of a flaring event (e.g., strong Hydrogen Balmer emission lines). This object does not exhibit kinematics similar to any known kinematic association. The LaTE-MoVeRS catalog is available through SDSS CasJobs and VizieR. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.05252v1-abstract-full').style.display = 'none'; document.getElementById('1612.05252v1-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 December, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in AJ. 18 pages including 14 figures and 5 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1610.07679">arXiv:1610.07679</a> <span> [<a href="https://arxiv.org/pdf/1610.07679">pdf</a>, <a href="https://arxiv.org/ps/1610.07679">ps</a>, <a href="https://arxiv.org/format/1610.07679">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</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/10.3847/0004-6256/152/6/209">10.3847/0004-6256/152/6/209 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Jupiter's Phase Variations from Cassini: a testbed for future direct-imaging missions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mayorga%2C+L+C">L. C. Mayorga</a>, <a href="/search/astro-ph?searchtype=author&query=Jackiewicz%2C+J">J. Jackiewicz</a>, <a href="/search/astro-ph?searchtype=author&query=Rages%2C+K">K. Rages</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">R. A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Knowles%2C+B">B. Knowles</a>, <a href="/search/astro-ph?searchtype=author&query=Lewis%2C+N">N. Lewis</a>, <a href="/search/astro-ph?searchtype=author&query=Marley%2C+M+S">M. S. Marley</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="1610.07679v1-abstract-short" style="display: inline;"> We present phase curves of Jupiter from 0-140 degrees as measured in multiple optical bandpasses by Cassini/ISS during the Millennium flyby of Jupiter in late 2000 to early 2001. Phase curves are of interest for studying the energy balance of Jupiter and understanding the scattering behavior of Jupiter as an exoplanet analog. We find that Jupiter is significantly darker at partial phases than an i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.07679v1-abstract-full').style.display = 'inline'; document.getElementById('1610.07679v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1610.07679v1-abstract-full" style="display: none;"> We present phase curves of Jupiter from 0-140 degrees as measured in multiple optical bandpasses by Cassini/ISS during the Millennium flyby of Jupiter in late 2000 to early 2001. Phase curves are of interest for studying the energy balance of Jupiter and understanding the scattering behavior of Jupiter as an exoplanet analog. We find that Jupiter is significantly darker at partial phases than an idealized Lambertian planet by roughly 25% and is not well fit by Jupiter-like exoplanet atmospheric models across all wavelengths. We provide analytic fits to Jupiter's phase function in several Cassini/ISS imaging filter bandpasses. In addition, these observations show that Jupiter's color is more variable with phase angle than predicted by models. Therefore, the color of even a near Jupiter-twin planet observed at a partial phase cannot be assumed to be comparable to that of Jupiter at full phase. We discuss how WFIRST and other future direct-imaging missions can enhance the study of cool giants. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.07679v1-abstract-full').style.display = 'none'; document.getElementById('1610.07679v1-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 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">29 pages, 9 figures, accepted to AJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.09626">arXiv:1609.09626</a> <span> [<a href="https://arxiv.org/pdf/1609.09626">pdf</a>, <a href="https://arxiv.org/format/1609.09626">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> </div> <p class="title is-5 mathjax"> Saturn's Polar Atmosphere </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sayanagi%2C+K+M">Kunio M. Sayanagi</a>, <a href="/search/astro-ph?searchtype=author&query=Baines%2C+K+H">Kevin H. Baines</a>, <a href="/search/astro-ph?searchtype=author&query=Dyudina%2C+U+A">Ulyana A. Dyudina</a>, <a href="/search/astro-ph?searchtype=author&query=Fletcher%2C+L+N">Leigh N. Fletcher</a>, <a href="/search/astro-ph?searchtype=author&query=S%C3%A1nchez-Lavega%2C+A">Agustin S谩nchez-Lavega</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</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="1609.09626v2-abstract-short" style="display: inline;"> This book chapter, Saturn's Polar Atmosphere, is to be published by Cambridge University Press as part of a multi-volume work edited by Kevin Baines, Michael Flasar, Norbert Krupp, and Thomas Stallard, entitled "Saturn in the 21st Century." This chapter reviews the state of our knowledge about Saturn's polar atmosphere that has been revealed through Earth- and space-based observation as well as th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.09626v2-abstract-full').style.display = 'inline'; document.getElementById('1609.09626v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.09626v2-abstract-full" style="display: none;"> This book chapter, Saturn's Polar Atmosphere, is to be published by Cambridge University Press as part of a multi-volume work edited by Kevin Baines, Michael Flasar, Norbert Krupp, and Thomas Stallard, entitled "Saturn in the 21st Century." This chapter reviews the state of our knowledge about Saturn's polar atmosphere that has been revealed through Earth- and space-based observation as well as theoretical and numerical modeling. In particular, the Cassini mission to Saturn, which has been in orbit around the ringed planet since 2004, has revolutionized our understanding of the planet. The current review updates a previous review by Del Genio et al (2009; Saturn Atmospheric Structure and Dynamics, Chapter 7 of "Saturn from Cassini-Huygens"), written after Cassini's primary mission phase that ended in 2008, by focusing on the north polar region of Saturn and comparing it to the southern high latitudes. Two prominent features in the northern high latitudes are the northern hexagon and the north polar vortex; we extensively review observational and theoretical investigations to date of both features. We also review the seasonal evolution of the polar regions using the observational data accumulated during the Cassini mission since 2004 (shortly after the northern winter solstice in 2002), through the equinox in 2009, and approaching the next solstice in 2017. We conclude the current review by listing unanswered questions and describing the observations of the polar regions planned for the Grand Finale phase of the Cassini mission between 2016 and 2017. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.09626v2-abstract-full').style.display = 'none'; document.getElementById('1609.09626v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">2016-10-03: Typo in the spelling of co-author Agustin S谩nchez-Lavega's name has been corrected, and moved the first sentence now of the abstract from the comments section</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1607.07246">arXiv:1607.07246</a> <span> [<a href="https://arxiv.org/pdf/1607.07246">pdf</a>, <a href="https://arxiv.org/ps/1607.07246">ps</a>, <a href="https://arxiv.org/format/1607.07246">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</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.icarus.2012.12.013">10.1016/j.icarus.2012.12.013 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dynamics of Saturn's great storm of 2010-2011 from Cassini ISS and RPWS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sayanagi%2C+K+M">Kunio M. Sayanagi</a>, <a href="/search/astro-ph?searchtype=author&query=Dyudina%2C+U+A">Ulyana A. Dyudina</a>, <a href="/search/astro-ph?searchtype=author&query=Ewald%2C+S+P">Shawn P. Ewald</a>, <a href="/search/astro-ph?searchtype=author&query=Fischer%2C+G">Georg Fischer</a>, <a href="/search/astro-ph?searchtype=author&query=Ingersoll%2C+A+P">Andrew P. Ingersoll</a>, <a href="/search/astro-ph?searchtype=author&query=Kurth%2C+W+S">William S. Kurth</a>, <a href="/search/astro-ph?searchtype=author&query=Muro%2C+G+D">Gabriel D. Muro</a>, <a href="/search/astro-ph?searchtype=author&query=Porco%2C+C+C">Carolyn C. Porco</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</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="1607.07246v1-abstract-short" style="display: inline;"> Saturn's quasi-periodic planet-encircling storms are the largest convecting outbursts in the Solar System. The last eruption was in 1990. A new eruption started in December 2010 and presented the first-ever opportunity to observe such episodic storms from a spacecraft in orbit around Saturn. Here, we analyze images acquired with the Cassini Imaging Science Subsystem (ISS), which captured the storm… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.07246v1-abstract-full').style.display = 'inline'; document.getElementById('1607.07246v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1607.07246v1-abstract-full" style="display: none;"> Saturn's quasi-periodic planet-encircling storms are the largest convecting outbursts in the Solar System. The last eruption was in 1990. A new eruption started in December 2010 and presented the first-ever opportunity to observe such episodic storms from a spacecraft in orbit around Saturn. Here, we analyze images acquired with the Cassini Imaging Science Subsystem (ISS), which captured the storm's birth, evolution and demise. In studying the end of the convective activity, we also analyze the Saturn Electrostatic Discharge (SED) signals detected by the Radio and Plasma Wave Science (RPWS) instrument. [...] <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.07246v1-abstract-full').style.display = 'none'; document.getElementById('1607.07246v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 July, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Icarus 223 (2013) 460-478 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.06296">arXiv:1602.06296</a> <span> [<a href="https://arxiv.org/pdf/1602.06296">pdf</a>, <a href="https://arxiv.org/format/1602.06296">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/10.3847/0004-6256/151/5/114">10.3847/0004-6256/151/5/114 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Using Close White Dwarf + M Dwarf Stellar Pairs to Constrain the Flare Rates in Close Stellar Binaries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Morgan%2C+D+P">Dylan P. Morgan</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Becker%2C+A+C">Andrew C. Becker</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1602.06296v1-abstract-short" style="display: inline;"> We present a study of the statistical flare rates of M dwarfs (dMs) with close white dwarf (WD) companions (WD+dM; typical separations < 1 au). Our previous analysis demonstrated that dMs with close WD companions are more magnetically active than their field counterparts. One likely implication of having a close binary companion is increased stellar rotation through disk-disruption, tidal effects,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.06296v1-abstract-full').style.display = 'inline'; document.getElementById('1602.06296v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.06296v1-abstract-full" style="display: none;"> We present a study of the statistical flare rates of M dwarfs (dMs) with close white dwarf (WD) companions (WD+dM; typical separations < 1 au). Our previous analysis demonstrated that dMs with close WD companions are more magnetically active than their field counterparts. One likely implication of having a close binary companion is increased stellar rotation through disk-disruption, tidal effects, and/or angular momentum exchange; increased stellar rotation has long been associated with an increase in stellar activity. Previous studies show a strong correlation between dMs that are magnetically active (showing H伪 in emission) and the frequency of stellar flare rates. We examine the difference between the flare rates observed in close WD+dM binary systems and field dMs. Our sample consists of a subset of 181 close WD+dM pairs from Morgan et al. (2012) observed in the Sloan Digital Sky Survey Stripe 82, where we obtain multi-epoch observations in the Sloan ugriz-bands. We find an increase in the overall flaring fraction in the close WD+dM pairs (0.09$\pm$0.03%) compared to the field dMs (0.0108$\pm$0.0007%; Kowalski et al. 2009) and a lower flaring fraction for active WD+dMs (0.05$\pm$0.03%) compared to active dMs (0.28$\pm$0.05%; Kowalski et al. 2009). We discuss how our results constrain both the single and binary dM flare rates. Our results also constrain dM multiplicity, our knowledge of the Galactic transient background, and may be important for the habitability of attending planets around dMs with close companions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.06296v1-abstract-full').style.display = 'none'; document.getElementById('1602.06296v1-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 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 7 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/1511.00957">arXiv:1511.00957</a> <span> [<a href="https://arxiv.org/pdf/1511.00957">pdf</a>, <a href="https://arxiv.org/format/1511.00957">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> </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/10.3847/0004-637X/821/2/93">10.3847/0004-637X/821/2/93 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The rotation and Galactic kinematics of mid M dwarfs in the Solar Neighborhood </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Newton%2C+E+R">Elisabeth R. Newton</a>, <a href="/search/astro-ph?searchtype=author&query=Irwin%2C+J">Jonathan Irwin</a>, <a href="/search/astro-ph?searchtype=author&query=Charbonneau%2C+D">David Charbonneau</a>, <a href="/search/astro-ph?searchtype=author&query=Berta-Thompson%2C+Z+K">Zachory K. Berta-Thompson</a>, <a href="/search/astro-ph?searchtype=author&query=Dittmann%2C+J+A">Jason A. Dittmann</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</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="1511.00957v2-abstract-short" style="display: inline;"> Rotation is a directly-observable stellar property, and drives magnetic field generation and activity through a magnetic dynamo. Main sequence stars with masses below approximately 0.35Msun (mid-to-late M dwarfs) are fully-convective, and are expected to have a different type of dynamo mechanism than solar-type stars. Measurements of their rotation rates provide insights into these mechanisms, but… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.00957v2-abstract-full').style.display = 'inline'; document.getElementById('1511.00957v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1511.00957v2-abstract-full" style="display: none;"> Rotation is a directly-observable stellar property, and drives magnetic field generation and activity through a magnetic dynamo. Main sequence stars with masses below approximately 0.35Msun (mid-to-late M dwarfs) are fully-convective, and are expected to have a different type of dynamo mechanism than solar-type stars. Measurements of their rotation rates provide insights into these mechanisms, but few rotation periods are available for these stars at field ages. Using photometry from the MEarth transit survey, we measure rotation periods for 387 nearby, mid-to-late M dwarfs in the Northern hemisphere, finding periods from 0.1 to 140 days. The typical detected rotator has stable, sinusoidal photometric modulations at a semi-amplitude of 0.5 to 1%. We find no period-amplitude relation for stars below 0.25Msun and an anti-correlation between period and amplitude for higher-mass M dwarfs. We highlight the existence of older, slowly-rotating stars without H伪 emission that nevertheless have strong photometric variability. The Galactic kinematics of our sample is consistent with the local population of G and K dwarfs, and rotators have metallicities characteristic of the Solar Neighborhood. We use the W space velocities and established age-velocity relations to estimate that stars with P<10 days are on average <2 Gyrs, and that those with P>70 days are about 5 Gyrs. The period distribution is mass dependent: as the mass decreases, the slowest rotators at a given mass have longer periods, and the fastest rotators have shorter periods. We find a lack of stars with intermediate rotation periods. [Abridged] <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.00957v2-abstract-full').style.display = 'none'; document.getElementById('1511.00957v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 November, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted to ApJ. Machine readable tables and additional figures are available in the published article or on request</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1510.08394">arXiv:1510.08394</a> <span> [<a href="https://arxiv.org/pdf/1510.08394">pdf</a>, <a href="https://arxiv.org/format/1510.08394">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1538-3873/128/959/018007">10.1088/1538-3873/128/959/018007 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Titan Science with the James Webb Space Telescope (JWST) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nixon%2C+C+A">Conor A. Nixon</a>, <a href="/search/astro-ph?searchtype=author&query=Achterberg%2C+R+K">Richard K. Achterberg</a>, <a href="/search/astro-ph?searchtype=author&query=Adamkovics%2C+M">Mate Adamkovics</a>, <a href="/search/astro-ph?searchtype=author&query=Bezard%2C+B">Bruno Bezard</a>, <a href="/search/astro-ph?searchtype=author&query=Bjoraker%2C+G+L">Gordon L. Bjoraker</a>, <a href="/search/astro-ph?searchtype=author&query=Cornet%2C+T">Thomas Cornet</a>, <a href="/search/astro-ph?searchtype=author&query=Hayes%2C+A+G">Alexander G. Hayes</a>, <a href="/search/astro-ph?searchtype=author&query=Lellouch%2C+E">Emmanuel Lellouch</a>, <a href="/search/astro-ph?searchtype=author&query=Lemmon%2C+M+T">Mark T. Lemmon</a>, <a href="/search/astro-ph?searchtype=author&query=Lopez-Puertas%2C+M">Manuel Lopez-Puertas</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+S">Sebastien Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Sotin%2C+C">Christophe Sotin</a>, <a href="/search/astro-ph?searchtype=author&query=Teanby%2C+N+A">Nicholas A. Teanby</a>, <a href="/search/astro-ph?searchtype=author&query=Turtle%2C+E+P">Elizabeth P. Turtle</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</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="1510.08394v1-abstract-short" style="display: inline;"> The James Webb Space Telescope (JWST), scheduled for launch in 2018, is the successor to the Hubble Space Telescope (HST) but with a significantly larger aperture (6.5 m) and advanced instrumentation focusing on infrared science (0.6-28.0 $渭$m ). In this paper we examine the potential for scientific investigation of Titan using JWST, primarily with three of the four instruments: NIRSpec, NIRCam an… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.08394v1-abstract-full').style.display = 'inline'; document.getElementById('1510.08394v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1510.08394v1-abstract-full" style="display: none;"> The James Webb Space Telescope (JWST), scheduled for launch in 2018, is the successor to the Hubble Space Telescope (HST) but with a significantly larger aperture (6.5 m) and advanced instrumentation focusing on infrared science (0.6-28.0 $渭$m ). In this paper we examine the potential for scientific investigation of Titan using JWST, primarily with three of the four instruments: NIRSpec, NIRCam and MIRI, noting that science with NIRISS will be complementary. Five core scientific themes are identified: (i) surface (ii) tropospheric clouds (iii) tropospheric gases (iv) stratospheric composition and (v) stratospheric hazes. We discuss each theme in depth, including the scientific purpose, capabilities and limitations of the instrument suite, and suggested observing schemes. We pay particular attention to saturation, which is a problem for all three instruments, but may be alleviated for NIRCam through use of selecting small sub-arrays of the detectors - sufficient to encompass Titan, but with significantly faster read-out times. We find that JWST has very significant potential for advancing Titan science, with a spectral resolution exceeding the Cassini instrument suite at near-infrared wavelengths, and a spatial resolution exceeding HST at the same wavelengths. In particular, JWST will be valuable for time-domain monitoring of Titan, given a five to ten year expected lifetime for the observatory, for example monitoring the seasonal appearance of clouds. JWST observations in the post-Cassini period will complement those of other large facilities such as HST, ALMA, SOFIA and next-generation ground-based telescopes (TMT, GMT, EELT). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.08394v1-abstract-full').style.display = 'none'; document.getElementById('1510.08394v1-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 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">50 pages, including 22 figures and 2 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1510.05690">arXiv:1510.05690</a> <span> [<a href="https://arxiv.org/pdf/1510.05690">pdf</a>, <a href="https://arxiv.org/format/1510.05690">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> </div> <p class="title is-5 mathjax"> Saturn's Seasonally Changing Atmosphere: Thermal Structure, Composition and Aerosols </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fletcher%2C+L+N">Leigh N. Fletcher</a>, <a href="/search/astro-ph?searchtype=author&query=Greathouse%2C+T+K">Thomas K. Greathouse</a>, <a href="/search/astro-ph?searchtype=author&query=Moses%2C+J+I">Julianne I. Moses</a>, <a href="/search/astro-ph?searchtype=author&query=Guerlet%2C+S">Sandrine Guerlet</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+R+A">Robert A. West</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="1510.05690v1-abstract-short" style="display: inline;"> The longevity of Cassini's exploration of Saturn's atmosphere (a third of a Saturnian year) means that we have been able to track the seasonal evolution of atmospheric temperatures, chemistry and cloud opacity over almost every season, from solstice to solstice and from perihelion to aphelion. Cassini has built upon the decades-long ground-based record to observe seasonal shifts in atmospheric tem… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.05690v1-abstract-full').style.display = 'inline'; document.getElementById('1510.05690v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1510.05690v1-abstract-full" style="display: none;"> The longevity of Cassini's exploration of Saturn's atmosphere (a third of a Saturnian year) means that we have been able to track the seasonal evolution of atmospheric temperatures, chemistry and cloud opacity over almost every season, from solstice to solstice and from perihelion to aphelion. Cassini has built upon the decades-long ground-based record to observe seasonal shifts in atmospheric temperature, finding a thermal response that lags behind the seasonal insolation with a lag time that increases with depth into the atmosphere, in agreement with radiative climate models. Seasonal hemispheric contrasts are perturbed at smaller scales by atmospheric circulation, such as belt/zone dynamics, the equatorial oscillations and the polar vortices. Temperature asymmetries are largest in the middle stratosphere and become insignificant near the radiative-convective boundary. Cassini has also measured southern-summertime asymmetries in atmospheric composition, including ammonia (the key species for the topmost clouds), phosphine and para-hydrogen (both disequilibrium species) in the upper troposphere; and hydrocarbons deriving from the UV photolysis of methane in the stratosphere (principally ethane and acetylene). These chemical asymmetries are now altering in subtle ways due to (i) the changing chemical efficiencies with temperature and insolation; and (ii) vertical motions associated with large-scale overturning in response to the seasonal temperature contrasts. Similarly, hemispheric contrasts in tropospheric aerosol opacity and coloration that were identified during the earliest phases of Cassini's exploration have now reversed, suggesting an intricate link between the clouds and the temperatures. [Abridged] <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.05690v1-abstract-full').style.display = 'none'; document.getElementById('1510.05690v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">34 pages, 20 figures, accepted for publication by Cambridge University Press as part of a multi-volume work edited by Kevin Baines, Michael Flasar, Norbert Krupp, and Thomas Stallard, entitled "Saturn in the 21st Century." The copy of the Chapter, as displayed on this website, is a draft, pre-publication copy only</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.03645">arXiv:1509.03645</a> <span> [<a href="https://arxiv.org/pdf/1509.03645">pdf</a>, <a href="https://arxiv.org/format/1509.03645">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> </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/10.3847/0004-637X/817/1/1">10.3847/0004-637X/817/1/1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Catalog of GALEX Ultraviolet Emission from Spectroscopically Confirmed M Dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Jones%2C+D+O">David O. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</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="1509.03645v1-abstract-short" style="display: inline;"> We present a catalog of GALEX Near-UV (NUV) and Far-UV (FUV) photometry for the Palomar/MSU and SDSS DR7 spectroscopic M dwarf catalogs. The catalog contains NUV measurements matched to 577 spectroscopically confirmed M dwarfs and FUV measurements matched to 150 spectroscopically confirmed M dwarfs. Using these data, we find that NUV and FUV luminosities strongly correlate with H伪 emission, a typi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.03645v1-abstract-full').style.display = 'inline'; document.getElementById('1509.03645v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.03645v1-abstract-full" style="display: none;"> We present a catalog of GALEX Near-UV (NUV) and Far-UV (FUV) photometry for the Palomar/MSU and SDSS DR7 spectroscopic M dwarf catalogs. The catalog contains NUV measurements matched to 577 spectroscopically confirmed M dwarfs and FUV measurements matched to 150 spectroscopically confirmed M dwarfs. Using these data, we find that NUV and FUV luminosities strongly correlate with H伪 emission, a typical indicator of magnetic activity in M dwarfs. We also examine the fraction of M dwarfs with varying degrees of strong line emission at NUV wavelengths. Our results indicate that the frequency of M dwarf NUV emission peaks at intermediate spectral types, with at least ~30% of young M4-M5 dwarfs having some level of activity. For mid-type M dwarfs, we show that NUV emission decreases with distance from the Galactic plane, a proxy for stellar age. Our complete matched source catalog is available online. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.03645v1-abstract-full').style.display = 'none'; document.getElementById('1509.03645v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 9 figures, accepted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.01907">arXiv:1509.01907</a> <span> [<a href="https://arxiv.org/pdf/1509.01907">pdf</a>, <a href="https://arxiv.org/format/1509.01907">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> </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/10.3847/0004-6256/151/2/41">10.3847/0004-6256/151/2/41 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Motion Verified Red Stars (MoVeRS): A Catalog of Proper Motion Selected Low-mass Stars from WISE, SDSS, and 2MASS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Theissen%2C+C+A">Christopher A. Theissen</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Dhital%2C+S">Saurav Dhital</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="1509.01907v2-abstract-short" style="display: inline;"> We present a photometric catalog of 8,735,004 proper motion selected low-mass stars (KML-spectral types) within the Sloan Digital Sky Survey (SDSS) footprint, from the combined SDSS Data Release 10 (DR10), Two-Micron All-Sky Survey (2MASS) Point Source Catalog (PSC), and Wide-field Infrared Survey Explorer (WISE) AllWISE catalog. Stars were selected using $r-i$, $i-z$, $r-z$, $z-J$, and $z-W1$ col… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.01907v2-abstract-full').style.display = 'inline'; document.getElementById('1509.01907v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.01907v2-abstract-full" style="display: none;"> We present a photometric catalog of 8,735,004 proper motion selected low-mass stars (KML-spectral types) within the Sloan Digital Sky Survey (SDSS) footprint, from the combined SDSS Data Release 10 (DR10), Two-Micron All-Sky Survey (2MASS) Point Source Catalog (PSC), and Wide-field Infrared Survey Explorer (WISE) AllWISE catalog. Stars were selected using $r-i$, $i-z$, $r-z$, $z-J$, and $z-W1$ colors, and SDSS, WISE, and 2MASS astrometry was combined to compute proper motions. The resulting 3,518,150 stars were augmented with proper motions for 5,216,854 earlier type stars from the combined SDSS and United States Naval Observatory B1.0 catalog (USNO-B). We used SDSS+USNO-B proper motions to determine the best criteria for selecting a clean sample of stars. Only stars whose proper motions were greater than their $2$$蟽$ uncertainty were included. Our Motion Verified Red Stars (MoVeRS) catalog is available through SDSS CasJobs and VizieR. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.01907v2-abstract-full').style.display = 'none'; document.getElementById('1509.01907v2-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, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 18 figures, 8 tables, accepted for publication in AJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.01591">arXiv:1509.01591</a> <span> [<a href="https://arxiv.org/pdf/1509.01591">pdf</a>, <a href="https://arxiv.org/format/1509.01591">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"> Runaway M Dwarf Candidates from the Sloan Digital Sky Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Favia%2C+A">Andrej Favia</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Theissen%2C+C+A">Christopher A. Theissen</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="1509.01591v1-abstract-short" style="display: inline;"> We present a sample of 20 runaway M dwarf candidates (RdMs) within 1 kpc of the Sun whose Galactocentric velocities exceed 400 km s$^{-1}$. The candidates were selected from the SDSS DR7 M Dwarf Catalog of West et al. (2011). Our RdMs have SDSS+USNO-B proper motions that are consistent with those recorded in the PPMXL, LSPM, and combined WISE+SDSS+2MASS catalogs. Sixteen RdMs are classified as dwa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.01591v1-abstract-full').style.display = 'inline'; document.getElementById('1509.01591v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.01591v1-abstract-full" style="display: none;"> We present a sample of 20 runaway M dwarf candidates (RdMs) within 1 kpc of the Sun whose Galactocentric velocities exceed 400 km s$^{-1}$. The candidates were selected from the SDSS DR7 M Dwarf Catalog of West et al. (2011). Our RdMs have SDSS+USNO-B proper motions that are consistent with those recorded in the PPMXL, LSPM, and combined WISE+SDSS+2MASS catalogs. Sixteen RdMs are classified as dwarfs, while the remaining four RdMs are subdwarfs. We model the Galactic potential using a bulge-disk-halo profile (Kenyon et al. 2008; Brown et al. 2014). Our fastest RdM, with Galactocentric velocity 658.5 $\pm$ 236.9 km s$^{-1}$, is a possible hypervelocity candidate, as it is unbound in 77% of our simulations. About half of our RdMs have kinematics that are consistent with ejection from the Galactic center. Seven of our RdMs have kinematics consistent with an ejection scenario from M31 or M32 to within 2蟽, although our distance-limited survey makes such a realization unlikely. No more than four of our RdMs may have originated from the Leo stream. We propose that to within measurement errors, most of our bound RdMs are likely disk runaways or halo objects, and may have been accelerated through a series of multi-body interactions within the Galactic disk or possibly supernovae explosions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.01591v1-abstract-full').style.display = 'none'; document.getElementById('1509.01591v1-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, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 5 figures, paper has been 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/1509.01590">arXiv:1509.01590</a> <span> [<a href="https://arxiv.org/pdf/1509.01590">pdf</a>, <a href="https://arxiv.org/ps/1509.01590">ps</a>, <a href="https://arxiv.org/format/1509.01590">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/10.1088/0004-637X/812/1/3">10.1088/0004-637X/812/1/3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An Activity-Rotation Relationship and Kinematic Analysis of Nearby Mid-to-Late-type M Dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Weisenburger%2C+K+L">Kolby L. Weisenburger</a>, <a href="/search/astro-ph?searchtype=author&query=Irwin%2C+J">Jonathan Irwin</a>, <a href="/search/astro-ph?searchtype=author&query=Berta-Thompson%2C+Z+K">Zachory K. Berta-Thompson</a>, <a href="/search/astro-ph?searchtype=author&query=Charbonneau%2C+D">David Charbonneau</a>, <a href="/search/astro-ph?searchtype=author&query=Dittmann%2C+J">Jason Dittmann</a>, <a href="/search/astro-ph?searchtype=author&query=Pineda%2C+J+S">J. Sebastian Pineda</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="1509.01590v1-abstract-short" style="display: inline;"> Using spectroscopic observations and photometric light curves of 238 nearby M dwarfs from the MEarth exoplanet transit survey, we examine the relationships between magnetic activity (quantified by H-alpha emission), rotation period, and stellar age. Previous attempts to investigate the relationship between magnetic activity and rotation in these stars were hampered by the limited number of M dwarf… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.01590v1-abstract-full').style.display = 'inline'; document.getElementById('1509.01590v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.01590v1-abstract-full" style="display: none;"> Using spectroscopic observations and photometric light curves of 238 nearby M dwarfs from the MEarth exoplanet transit survey, we examine the relationships between magnetic activity (quantified by H-alpha emission), rotation period, and stellar age. Previous attempts to investigate the relationship between magnetic activity and rotation in these stars were hampered by the limited number of M dwarfs with measured rotation periods (and the fact that vsini measurements probe only rapid rotation). However, the photometric data from MEarth allows us to probe a wide range of rotation periods for hundreds of M dwarf stars (from shorter than than one to longer than 100 days). Over all M spectral types that we probe, we find that the presence of magnetic activity is tied to rotation, including for late-type, fully convective M dwarfs. We also find evidence that the fraction of late-type M dwarfs that are active may be higher at longer rotation periods compared to their early-type counterparts, with several active, late-type, slowly rotating stars present in our sample. Additionally, we find that all M dwarfs with rotation periods shorter than 26 days (early-type; M1-M4) and 86 days (late-type; M5-M8) are magnetically active. This potential mismatch suggests that the physical mechanisms that connect stellar rotation to chromospheric heating may be different in fully convective stars. A kinematic analysis suggests that the magnetically active, rapidly rotating stars are consistent with a kinematically young population, while slow-rotators are less active or inactive and appear to belong to an older, dynamically heated stellar population. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.01590v1-abstract-full').style.display = 'none'; document.getElementById('1509.01590v1-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, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 9 figures, 2 tables, accepted for publication in the Astrophysical Journal (full tables are available in online journal or by request)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1507.02333">arXiv:1507.02333</a> <span> [<a href="https://arxiv.org/pdf/1507.02333">pdf</a>, <a href="https://arxiv.org/format/1507.02333">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/10.1088/0004-637X/809/2/161">10.1088/0004-637X/809/2/161 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Linking Stellar Coronal Activity and Rotation at 500 Myr: A Deep Chandra Observation of M37 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=N%C3%BA%C3%B1ez%2C+A">Alejandro N煤帽ez</a>, <a href="/search/astro-ph?searchtype=author&query=Ag%C3%BCeros%2C+M+A">Marcel A. Ag眉eros</a>, <a href="/search/astro-ph?searchtype=author&query=Covey%2C+K+R">Kevin R. Covey</a>, <a href="/search/astro-ph?searchtype=author&query=Hartman%2C+J+D">Joel D. Hartman</a>, <a href="/search/astro-ph?searchtype=author&query=Kraus%2C+A+L">Adam L. Kraus</a>, <a href="/search/astro-ph?searchtype=author&query=Bowsher%2C+E+C">Emily C. Bowsher</a>, <a href="/search/astro-ph?searchtype=author&query=Douglas%2C+S+T">Stephanie T. Douglas</a>, <a href="/search/astro-ph?searchtype=author&query=L%C3%B3pez-Morales%2C+M">Mercedes L贸pez-Morales</a>, <a href="/search/astro-ph?searchtype=author&query=Pooley%2C+D+A">David A. Pooley</a>, <a href="/search/astro-ph?searchtype=author&query=Posselt%2C+B">Bettina Posselt</a>, <a href="/search/astro-ph?searchtype=author&query=Saar%2C+S+H">Steven H. Saar</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</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="1507.02333v2-abstract-short" style="display: inline;"> Empirical calibrations of the stellar age-rotation-activity relation (ARAR) rely on observations of the co-eval populations of stars in open clusters. We used the Chandra X-ray Observatory to study M37, a 500-Myr-old open cluster that has been extensively surveyed for rotation periods ($P_{\rm rot}$). M37 was observed almost continuously for five days, for a total of 440.5 ksec, to measure stellar… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.02333v2-abstract-full').style.display = 'inline'; document.getElementById('1507.02333v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1507.02333v2-abstract-full" style="display: none;"> Empirical calibrations of the stellar age-rotation-activity relation (ARAR) rely on observations of the co-eval populations of stars in open clusters. We used the Chandra X-ray Observatory to study M37, a 500-Myr-old open cluster that has been extensively surveyed for rotation periods ($P_{\rm rot}$). M37 was observed almost continuously for five days, for a total of 440.5 ksec, to measure stellar X-ray luminosities ($L_{\mathrm{X}}$), a proxy for coronal activity, across a wide range of masses. The cluster's membership catalog was revisited to calculate updated membership probabilities from photometric data and each star's distance to the cluster center. The result is a comprehensive sample of 1699 M37 members: 426 with $P_{\rm rot}$, 278 with X-ray detections, and 76 with both. We calculate Rossby numbers, $R_o = P_{\rm rot}/蟿$, where $蟿$ is the convective turnover time, and ratios of the X-ray-to-bolometric luminosity, $L_{\rm X}/L_{\rm bol}$, to minimize mass dependencies in our characterization of the rotation-coronal activity relation at 500 Myr. We find that fast rotators, for which $R_o<0.09\pm0.01$, show saturated levels of activity, with log($L_{\rm X}/L_{\rm bol}$)$=-3.06\pm0.04$. For $R_o\geq0.09\pm0.01$, activity is unsaturated and follows a power law of the form $R_o^尾$, where $尾$=$-2.03_{-0.14}^{+0.17}$. This is the largest sample available for analyzing the dependence of coronal emission on rotation for a single-aged population, covering stellar masses in the range 0.4$-$1.3 $M_{\odot}$, $P_{\rm rot}$ in the range 0.4$-$12.8 d, and $L_{\rm X}$ in the range 10$^{28.4-30.5}$ erg s$^{-1}$. Our results make M37 a new benchmark open cluster for calibrating the ARAR at ages of $\approx$500 Myr. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.02333v2-abstract-full').style.display = 'none'; document.getElementById('1507.02333v2-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, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 July, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 22 figures, 8 tables, 2 machine-readable tables (MRT)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, 809, Issue 2, 161N (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1507.00057">arXiv:1507.00057</a> <span> [<a href="https://arxiv.org/pdf/1507.00057">pdf</a>, <a href="https://arxiv.org/ps/1507.00057">ps</a>, <a href="https://arxiv.org/format/1507.00057">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/10.1088/0067-0049/220/1/18">10.1088/0067-0049/220/1/18 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Brown Dwarf Kinematics Project (BDKP). IV. Radial Velocities of 85 Late-M and L dwarfs with MagE </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Burgasser%2C+A+J">Adam J. Burgasser</a>, <a href="/search/astro-ph?searchtype=author&query=Logsdon%2C+S+E">Sarah E. Logsdon</a>, <a href="/search/astro-ph?searchtype=author&query=Gagne%2C+J">Jonathan Gagne</a>, <a href="/search/astro-ph?searchtype=author&query=Bochanski%2C+J+J">John J. Bochanski</a>, <a href="/search/astro-ph?searchtype=author&query=Faherty%2C+J+K">Jaqueline K. Faherty</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Mamajek%2C+E+E">Eric E. Mamajek</a>, <a href="/search/astro-ph?searchtype=author&query=Schmidt%2C+S+J">Sarah J. Schmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Cruz%2C+K+L">Kelle L. Cruz</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="1507.00057v1-abstract-short" style="display: inline;"> Radial velocity measurements are presented for 85 late M- and L-type very low mass stars and brown dwarfs obtained with the Magellan Echellette (MagE) spectrograph. Targets primarily have distances within 20 pc of the Sun, with more distant sources selected for their unusual spectral energy distributions. We achieved precisions of 2--3 km/s, and combined these with astrometric and spectrophotometr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.00057v1-abstract-full').style.display = 'inline'; document.getElementById('1507.00057v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1507.00057v1-abstract-full" style="display: none;"> Radial velocity measurements are presented for 85 late M- and L-type very low mass stars and brown dwarfs obtained with the Magellan Echellette (MagE) spectrograph. Targets primarily have distances within 20 pc of the Sun, with more distant sources selected for their unusual spectral energy distributions. We achieved precisions of 2--3 km/s, and combined these with astrometric and spectrophotometric data to calculate $UVW$ velocities. Most are members of the thin disk of the Galaxy, and velocity dispersions indicate a mean age of 5.2$\pm$0.2 Gyr for sources within 20 pc. We find significantly different kinematic ages between late-M dwarfs (4.0$\pm$0.2 Gyr) and L dwarfs (6.5$\pm$0.4 Gyr) in our sample that are contrary to predictions from prior simulations. This difference appears to be driven by a dispersed population of unusually blue L dwarfs which may be more prevalent in our local volume-limited sample than in deeper magnitude-limited surveys. The L dwarfs exhibit an asymmetric $U$ velocity distribution with a net inward flow, similar to gradients recently detected in local stellar samples. Simulations incorporating brown dwarf evolution and Galactic orbital dynamics are unable to reproduce the velocity asymmetry, suggesting non-axisymmetric perturbations or two distinct L dwarf populations. We also find the L dwarfs to have a kinematic age-activity correlation similar to more massive stars. We identify several sources with low surface gravities, and two new substellar candidate members of nearby young moving groups: the astrometric binary DENIS J08230313$-$4912012AB, a low-probability member of the $尾$ Pictoris Moving Group; and 2MASS J15104786-2818174, a moderate-probability member of the 30-50 Myr Argus Association. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.00057v1-abstract-full').style.display = 'none'; document.getElementById('1507.00057v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 June, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">81 pages, 77 figures, accepted for publication to ApJS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1504.05249">arXiv:1504.05249</a> <span> [<a href="https://arxiv.org/pdf/1504.05249">pdf</a>, <a href="https://arxiv.org/format/1504.05249">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/10.1088/0004-6256/150/2/57">10.1088/0004-6256/150/2/57 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> SLoWPoKES-II: 100,000 Wide Binaries Identified in SDSS without Proper Motions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dhital%2C+S">Saurav Dhital</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Stassun%2C+K+G">Keivan G. Stassun</a>, <a href="/search/astro-ph?searchtype=author&query=Schluns%2C+K+J">Kyle J. Schluns</a>, <a href="/search/astro-ph?searchtype=author&query=Massey%2C+A+P">Angela P. Massey</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="1504.05249v2-abstract-short" style="display: inline;"> We present the SLoWPoKES-II catalog of low-mass visual binaries identified from the Sloan Digital Sky Survey by matching photometric distances. The candidate pairs are vetted by comparing the stellar density at their respective Galactic positions to Monte Carlo realizations of a simulated Milky Way. In this way, we are able to identify large numbers of bona fide wide binaries without the need of p… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1504.05249v2-abstract-full').style.display = 'inline'; document.getElementById('1504.05249v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1504.05249v2-abstract-full" style="display: none;"> We present the SLoWPoKES-II catalog of low-mass visual binaries identified from the Sloan Digital Sky Survey by matching photometric distances. The candidate pairs are vetted by comparing the stellar density at their respective Galactic positions to Monte Carlo realizations of a simulated Milky Way. In this way, we are able to identify large numbers of bona fide wide binaries without the need of proper motions. 105,537 visual binaries with angular separations of $\sim$1-20", are identified, each with a probability of chance alignment of $\lesssim$5%. This is the largest catalog of bona fide wide binaries to date, and it contains a diversity of systems---in mass, mass ratios, binary separations, metallicity, and evolutionary states---that should facilitate follow-up studies to characterize the properties of M dwarfs and white dwarfs. There is a subtle but definitive suggestion of multiple populations in the physical separation distribution, supporting earlier findings. We suggest that wide binaries are comprised of multiple populations, most likely representing different formation modes. There are 141 M7 or later wide binary candidates, representing a 7-fold increase in the number currently known. These binaries are too wide to have been formed via the ejection mechanism. Finally, we find that ~6% of spectroscopically confirmed M dwarfs are not included in the SDSS STAR catalog; they are misclassified as extended sources due to the presence of a nearby or partially resolved companion. The SLoWPoKES-II catalog is publicly available to the entire community on the world wide web via the Filtergraph data visualization portal. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1504.05249v2-abstract-full').style.display = 'none'; document.getElementById('1504.05249v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 April, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 April, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by AJ. 14 pages, 10 figures. Long tables omitted; see http://slowpokes.vanderbilt.edu/visualization.html instead</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1410.1514">arXiv:1410.1514</a> <span> [<a href="https://arxiv.org/pdf/1410.1514">pdf</a>, <a href="https://arxiv.org/ps/1410.1514">ps</a>, <a href="https://arxiv.org/format/1410.1514">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/10.1086/679329">10.1086/679329 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> H$伪$ Emission From Active Equal-mass, Wide M Dwarf Binaries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gunning%2C+H+C">Heather C. Gunning</a>, <a href="/search/astro-ph?searchtype=author&query=Schmidt%2C+S+J">Sarah J. Schmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Davenport%2C+J+R+A">James R. A. Davenport</a>, <a href="/search/astro-ph?searchtype=author&query=Dhital%2C+S">Saurav Dhital</a>, <a href="/search/astro-ph?searchtype=author&query=Hawley%2C+S+L">Suzanne L. Hawley</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</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="1410.1514v1-abstract-short" style="display: inline;"> We identify a sample of near-equal mass wide binary M dwarf systems from the SLoWPoKES catalog of common proper-motion binaries and obtain follow-up observations of their chromospheric activity as measured by the H$伪$ emission line. We present optical spectra for both components of 48 candidate M dwarf binaries, confirming their mid-M spectral types. Of those 48 coeval pairs, we find eight with H… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.1514v1-abstract-full').style.display = 'inline'; document.getElementById('1410.1514v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1410.1514v1-abstract-full" style="display: none;"> We identify a sample of near-equal mass wide binary M dwarf systems from the SLoWPoKES catalog of common proper-motion binaries and obtain follow-up observations of their chromospheric activity as measured by the H$伪$ emission line. We present optical spectra for both components of 48 candidate M dwarf binaries, confirming their mid-M spectral types. Of those 48 coeval pairs, we find eight with H$伪$ emission from both components, three with weak emission in one component and no emission in the other, and 37 with two inactive components. We find that of the eleven pairs with at least one active component, only three follow the net trend of decreasing activity strength $L_{\rm H伪}/L_{\rm bol}$ with later spectral type. The difference in quiescent activity strength between the A and B components is larger than what would be expected based on the small differences in color (mass). For five binaries with two active components, we present 47 hours of time-resolved spectroscopy, observed on the ARC 3.5-m over twelve different nights. For four of the five pairs, the slightly redder (B) component exhibits a higher level of H$伪$ emission during the majority of the observations and the redder objects are the only components to flare. The full range of H$伪$ emission observed on these variable mid-M dwarfs is comparable to the scatter in H$伪$ emission found in single-epoch surveys of mid-M dwarfs, indicating that variability could be a major factor in the spread of observed activity strengths. We also find that variability is independent of both activity strength and spectral type. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.1514v1-abstract-full').style.display = 'none'; document.getElementById('1410.1514v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 October, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 6 figures, accepted for publication in PASP</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1410.0014">arXiv:1410.0014</a> <span> [<a href="https://arxiv.org/pdf/1410.0014">pdf</a>, <a href="https://arxiv.org/ps/1410.0014">ps</a>, <a href="https://arxiv.org/format/1410.0014">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/10.1088/0004-6256/149/5/158">10.1088/0004-6256/149/5/158 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> BOSS Ultracool Dwarfs I: Colors and Magnetic Activity of M and L dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schmidt%2C+S+J">Sarah J. Schmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Hawley%2C+S+L">Suzanne L. Hawley</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Bochanski%2C+J+J">John J. Bochanski</a>, <a href="/search/astro-ph?searchtype=author&query=Davenport%2C+J+R+A">James R. A. Davenport</a>, <a href="/search/astro-ph?searchtype=author&query=Ge%2C+J">Jian Ge</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+D+P">Donald P. Schneider</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="1410.0014v1-abstract-short" style="display: inline;"> We present the colors and activity of ultracool (M7-L8) dwarfs from the Tenth Data Release of the Sloan Digital Sky Survey (SDSS). We combine previous samples of SDSS M and L dwarfs with new data obtained from the Baryon Oscillation Sky Survey (BOSS) to produce the BOSS Ultracool Dwarf (BUD) sample of 11820 M7-L8 dwarfs. By combining SDSS data with photometry from the Two Micron All Sky Survey and… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.0014v1-abstract-full').style.display = 'inline'; document.getElementById('1410.0014v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1410.0014v1-abstract-full" style="display: none;"> We present the colors and activity of ultracool (M7-L8) dwarfs from the Tenth Data Release of the Sloan Digital Sky Survey (SDSS). We combine previous samples of SDSS M and L dwarfs with new data obtained from the Baryon Oscillation Sky Survey (BOSS) to produce the BOSS Ultracool Dwarf (BUD) sample of 11820 M7-L8 dwarfs. By combining SDSS data with photometry from the Two Micron All Sky Survey and the Wide-Field Infrared Sky Explorer mission, we present ultracool dwarf colors from $i-z$ to $W2-W3$ as a function of spectral type, and extend the SDSS-2MASS-WISE color locus to include ultracool dwarfs. The $i-z$, $i-J$, and $z-J$ colors provide the best indication of spectral type for M7-L3 dwarfs. We also examine ultracool dwarf chromospheric activity through the presence and strength of H$伪$ emission. The fraction of active dwarfs rises through the M spectral sequence until it reaches $\sim$90% at spectral type L0. The fraction of active dwarfs then declines to 50% at spectral type L5; no H$伪$ emission is observed in the late-L dwarfs in the BUD sample. The fraction of active L0-L5 dwarfs is much higher than previously observed. The strength of activity declines with spectral type from M7 through L3, after which the data do not show a clear trend. Using one-dimensional chromosphere models, we explore the range of filling factors and chromospheric temperature structures that are consistent with H$伪$ observations of M0-L7 dwarfs. M dwarf chromospheres have a similar, smoothly varying range of temperature and surface coverage while L dwarf chromospheres are cooler and have smaller filling factors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.0014v1-abstract-full').style.display = 'none'; document.getElementById('1410.0014v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 September, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages and 13 figures, submitted to AJ. A short video describing these results can be found at https://www.youtube.com/watch?v=wwX5WkuJCU4</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1409.1229">arXiv:1409.1229</a> <span> [<a href="https://arxiv.org/pdf/1409.1229">pdf</a>, <a href="https://arxiv.org/format/1409.1229">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/10.1088/0004-637X/794/2/145">10.1088/0004-637X/794/2/145 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A New Sample of Cool Subdwarfs from SDSS: Properties and Kinematics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Savcheva%2C+A">Antonia Savcheva</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Bochanski%2C+J+J">John J. Bochanski</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="1409.1229v1-abstract-short" style="display: inline;"> We present a new sample of M subdwarfs compiled from the 7th data release of the Sloan Digital Sky Survey. With 3517 new subdwarfs, this new sample significantly increases the number of spectroscopically confirmed low-mass subdwarfs. This catalog also includes 905 extreme and 534 ultra sudwarfs. We present the entire catalog including observed and derived quantities, and template spectra created f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.1229v1-abstract-full').style.display = 'inline'; document.getElementById('1409.1229v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1409.1229v1-abstract-full" style="display: none;"> We present a new sample of M subdwarfs compiled from the 7th data release of the Sloan Digital Sky Survey. With 3517 new subdwarfs, this new sample significantly increases the number of spectroscopically confirmed low-mass subdwarfs. This catalog also includes 905 extreme and 534 ultra sudwarfs. We present the entire catalog including observed and derived quantities, and template spectra created from co-added subdwarf spectra. We show color-color and reduced proper motion diagrams of the three metallicity classes, which are shown to separate from the disk dwarf population. The extreme and ultra subdwarfs are seen at larger values of reduced proper motion as expected for more dynamically heated populations. We determine 3D kinematics for all of the stars with proper motions. The color-magnitude diagrams show a clear separation of the three metallicity classes with the ultra and extreme subdwarfs being significantly closer to the main sequence than the ordinary subdwarfs. All subdwarfs lie below (fainter) and to the left (bluer) of the main sequence. Based on the average $(U,V,W)$ velocities and their dispersions, the extreme and ultra subdwarfs likely belong to the Galactic halo, while the ordinary subdwarfs are likely part of the old Galactic (or thick) disk. An extensive activity analysis of subdwarfs is performed using H$伪$ emission and 208 active subdwarfs are found. We show that while the activity fraction of subdwarfs rises with spectral class and levels off at the latest spectral classes, consistent with the behavior of M dwarfs, the extreme and ultra subdwarfs are basically flat. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.1229v1-abstract-full').style.display = 'none'; document.getElementById('1409.1229v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 September, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">66 pages, 23 figures, 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/1409.0016">arXiv:1409.0016</a> <span> [<a href="https://arxiv.org/pdf/1409.0016">pdf</a>, <a href="https://arxiv.org/ps/1409.0016">ps</a>, <a href="https://arxiv.org/format/1409.0016">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/10.1088/0004-637X/794/2/146">10.1088/0004-637X/794/2/146 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Warm Dust around Cool Stars: Field M Dwarfs with WISE 12 or 22 Micron Excess Emission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Theissen%2C+C+A">Christopher A. Theissen</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</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="1409.0016v2-abstract-short" style="display: inline;"> Using the SDSS DR7 spectroscopic catalog, we searched the WISE AllWISE catalog to investigate the occurrence of warm dust, as inferred from IR excesses, around field M dwarfs (dMs). We developed SDSS/WISE color selection criteria to identify 175 dMs (from 70,841) that show IR flux greater than typical dM photosphere levels at 12 and/or 22 $渭$m, including seven new stars within the Orion OB1 footpr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.0016v2-abstract-full').style.display = 'inline'; document.getElementById('1409.0016v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1409.0016v2-abstract-full" style="display: none;"> Using the SDSS DR7 spectroscopic catalog, we searched the WISE AllWISE catalog to investigate the occurrence of warm dust, as inferred from IR excesses, around field M dwarfs (dMs). We developed SDSS/WISE color selection criteria to identify 175 dMs (from 70,841) that show IR flux greater than typical dM photosphere levels at 12 and/or 22 $渭$m, including seven new stars within the Orion OB1 footprint. We characterize the dust populations inferred from each IR excess, and investigate the possibility that these excesses could arise from ultracool binary companions by modeling combined SEDs. Our observed IR fluxes are greater than levels expected from ultracool companions ($>3蟽$). We also estimate that the probability the observed IR excesses are due to chance alignments with extragalactic sources is $<$ 0.1%. Using SDSS spectra we measure surface gravity dependent features (K, Na, and CaH 3), and find $<$ 15% of our sample indicate low surface gravities. Examining tracers of youth (H$伪$, UV fluxes, and Li absorption), we find $<$ 3% of our sample appear young, indicating we are observing a population of field stars $\gtrsim$ 1 Gyr, likely harboring circumstellar material. We investigate age-dependent properties probed by this sample, studying the disk fraction as a function of Galactic height. The fraction remains small and constant to $|Z| \sim 700$ pc, and then drops, indicating little to no trend with age. Possible explanations for disks around field dMs include: 1) collisions of planetary bodies, 2) tidal disruption of planetary bodies, or 3) failed planet formation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.0016v2-abstract-full').style.display = 'none'; document.getElementById('1409.0016v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 April, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 August, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">27 pages, 21 figures, 12 tables, Accepted for publication in ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Christopher A. Theissen and Andrew A. West 2014 ApJ 794 146 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1408.3089">arXiv:1408.3089</a> <span> [<a href="https://arxiv.org/pdf/1408.3089">pdf</a>, <a href="https://arxiv.org/ps/1408.3089">ps</a>, <a href="https://arxiv.org/format/1408.3089">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/10.1088/0004-637X/794/2/143">10.1088/0004-637X/794/2/143 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> SpeX Spectroscopy of Unresolved Very Low Mass Binaries. II. Identification of Fourteen Candidate Binaries with Late-M/Early-L and T Dwarf Components </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gagliuffi%2C+D+C+B">Daniella C. Bardalez Gagliuffi</a>, <a href="/search/astro-ph?searchtype=author&query=Burgasser%2C+A+J">Adam J. Burgasser</a>, <a href="/search/astro-ph?searchtype=author&query=Gelino%2C+C+R">Christopher R. Gelino</a>, <a href="/search/astro-ph?searchtype=author&query=Looper%2C+D+L">Dagny L. Looper</a>, <a href="/search/astro-ph?searchtype=author&query=Nicholls%2C+C+P">Christine P. Nicholls</a>, <a href="/search/astro-ph?searchtype=author&query=Schmidt%2C+S+J">Sarah J. Schmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Cruz%2C+K">Kelle Cruz</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Gizis%2C+J+E">John E. Gizis</a>, <a href="/search/astro-ph?searchtype=author&query=Metchev%2C+S">Stanimir Metchev</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="1408.3089v3-abstract-short" style="display: inline;"> Multiplicity is a key statistic for understanding the formation of very low mass (VLM) stars and brown dwarfs. Currently, the separation distribution of VLM binaries remains poorly constrained at small separations ($\leq$ 1 AU), leading to uncertainty in the overall binary fraction. We approach this problem by searching for late-M/early-L plus T dwarf spectral binaries whose combined light spectra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1408.3089v3-abstract-full').style.display = 'inline'; document.getElementById('1408.3089v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1408.3089v3-abstract-full" style="display: none;"> Multiplicity is a key statistic for understanding the formation of very low mass (VLM) stars and brown dwarfs. Currently, the separation distribution of VLM binaries remains poorly constrained at small separations ($\leq$ 1 AU), leading to uncertainty in the overall binary fraction. We approach this problem by searching for late-M/early-L plus T dwarf spectral binaries whose combined light spectra exhibit distinct peculiarities, allowing for separation-independent identification. We define a set of spectral indices designed to identify these systems, and use a spectral template fitting method to confirm and characterize spectral binary (SB) candidates from a library of 815 spectra from the SpeX Prism Spectral Libraries. We present eleven new binary candidates, confirm three previously reported candidates and rule out two previously identified candidates, all with primary and secondary spectral types between M7-L7 and T1-T8, respectively. We find that subdwarfs and blue L dwarfs are the primary contaminants in our sample and propose a method for segregating these sources. If confirmed by follow-up observations, these systems may add to the growing list of tight separation binaries, whose orbital properties may yield further insight into brown dwarf formation scenarios. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1408.3089v3-abstract-full').style.display = 'none'; document.getElementById('1408.3089v3-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, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 August, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">49 pages, 9 figures. v3 includes sigma values for table 4, and corrected table 3 and figure 2</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1407.2610">arXiv:1407.2610</a> <span> [<a href="https://arxiv.org/pdf/1407.2610">pdf</a>, <a href="https://arxiv.org/ps/1407.2610">ps</a>, <a href="https://arxiv.org/format/1407.2610">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> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/2041-8205/790/1/L5">10.1088/2041-8205/790/1/L5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Most Distant Stars in the Milky Way </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bochanski%2C+J+J">John J. Bochanski</a>, <a href="/search/astro-ph?searchtype=author&query=Willman%2C+B">Beth Willman</a>, <a href="/search/astro-ph?searchtype=author&query=Caldwell%2C+N">Nelson Caldwell</a>, <a href="/search/astro-ph?searchtype=author&query=Sanderson%2C+R">Robyn Sanderson</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">Jay Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Brown%2C+W">Warren Brown</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1407.2610v1-abstract-short" style="display: inline;"> We report on the discovery of the most distant Milky Way (MW) stars known to date: ULAS J001535.72$+$015549.6 and ULAS J074417.48$+$253233.0. These stars were selected as M giant candidates based on their infrared and optical colors and lack of proper motions. We spectroscopically confirmed them as outer halo giants using the MMT/Red Channel spectrograph. Both stars have large estimated distances,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.2610v1-abstract-full').style.display = 'inline'; document.getElementById('1407.2610v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1407.2610v1-abstract-full" style="display: none;"> We report on the discovery of the most distant Milky Way (MW) stars known to date: ULAS J001535.72$+$015549.6 and ULAS J074417.48$+$253233.0. These stars were selected as M giant candidates based on their infrared and optical colors and lack of proper motions. We spectroscopically confirmed them as outer halo giants using the MMT/Red Channel spectrograph. Both stars have large estimated distances, with ULAS J001535.72$+$015549.6 at $274 \pm 74$ kpc and ULAS J074417.48$+$253233.0 at 238 $\pm$ 64 kpc, making them the first MW stars discovered beyond 200 kpc. ULAS J001535.72$+$015549.6 and ULAS J074417.48$+$253233.0 are both moving away from the Galactic center at $52 \pm 10$ km s$^{-1}$ and $24 \pm 10$ km s$^{-1}$, respectively. Using their distances and kinematics, we considered possible origins such as: tidal stripping from a dwarf galaxy, ejection from the MW's disk, or membership in an undetected dwarf galaxy. These M giants, along with two inner halo giants that were also confirmed during this campaign, are the first to map largely unexplored regions of our Galaxy's outer halo. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.2610v1-abstract-full').style.display = 'none'; document.getElementById('1407.2610v1-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, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted and in print by ApJL. Seven pages, 2 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal Letters, 2014, Volume 790, Issue 1, article id. L5 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1406.1228">arXiv:1406.1228</a> <span> [<a href="https://arxiv.org/pdf/1406.1228">pdf</a>, <a href="https://arxiv.org/ps/1406.1228">ps</a>, <a href="https://arxiv.org/format/1406.1228">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/10.1086/677403">10.1086/677403 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Calibrating Ultracool Dwarfs: Optical Template Spectra, Bolometric Corrections, and $蠂$ Values </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schmidt%2C+S+J">Sarah J. Schmidt</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Bochanski%2C+J+J">John J. Bochanski</a>, <a href="/search/astro-ph?searchtype=author&query=Hawley%2C+S+L">Suzanne L. Hawley</a>, <a href="/search/astro-ph?searchtype=author&query=Kielty%2C+C">Collin Kielty</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1406.1228v1-abstract-short" style="display: inline;"> We present optical template spectra, bolometric corrections, and $蠂$ values for ultracool dwarfs. The templates are based on spectra from the Sloan Digital Sky Survey (SDSS) and the Astrophysical Research Consortium 3.5-m telescope. The spectral features and overall shape of the L dwarf templates are consistent with previous spectroscopic standards and the templates have a radial velocity precisio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.1228v1-abstract-full').style.display = 'inline'; document.getElementById('1406.1228v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1406.1228v1-abstract-full" style="display: none;"> We present optical template spectra, bolometric corrections, and $蠂$ values for ultracool dwarfs. The templates are based on spectra from the Sloan Digital Sky Survey (SDSS) and the Astrophysical Research Consortium 3.5-m telescope. The spectral features and overall shape of the L dwarf templates are consistent with previous spectroscopic standards and the templates have a radial velocity precision of $\sim$10--20 km s$^{-1}$. We calculate bolometric fluxes (accurate to 10--20\%) for 101 late-M and L dwarfs from SDSS, 2MASS, and WISE photometry, SDSS spectra, and BT-Settl model spectra. We find that the $z$- and $J$-band bolometric corrections for late-M and L dwarfs have a strong correlation with $z-J$ and $J-K_S$ colors respectively. The new $蠂$ values, which can be used to convert H$伪$ equivalent widths to activity strength, are based on spectrophotometrically calibrated SDSS spectra and the new bolometric fluxes. While the measured $蠂$ values have typical uncertainties of $\sim$20\%, ultracool dwarf models show the continuum surrounding H$伪$ can vary by up to an order of magnitude with changing surface gravity. Our semi-empirical $蠂$ values are one to two orders of magnitude larger than previous $蠂$ values for mid- to late-L dwarfs, indicating that the upper limits for H$伪$ activity strength on the coolest L dwarfs have been underestimated. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.1228v1-abstract-full').style.display = 'none'; document.getElementById('1406.1228v1-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 June, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 10 figures, PASP in press. L dwarf templates available at: http://www.astro.washington.edu/users/slh/templates/ltemplates/index.html</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1310.7565">arXiv:1310.7565</a> <span> [<a href="https://arxiv.org/pdf/1310.7565">pdf</a>, <a href="https://arxiv.org/ps/1310.7565">ps</a>, <a href="https://arxiv.org/format/1310.7565">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-6256/147/4/76">10.1088/0004-6256/147/4/76 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Hunting The Most Distant Stars in the Milky Way: Methods and Initial Results </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bochanski%2C+J+J">John J. Bochanski</a>, <a href="/search/astro-ph?searchtype=author&query=Willman%2C+B">Beth Willman</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+A+A">Andrew A. West</a>, <a href="/search/astro-ph?searchtype=author&query=Strader%2C+J">Jay Strader</a>, <a href="/search/astro-ph?searchtype=author&query=Chomiuk%2C+L">Laura Chomiuk</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="1310.7565v2-abstract-short" style="display: inline;"> We present a new catalog of 404 M giant candidates found in the UKIRT Infrared Deep Sky Survey (UKIDSS). The 2,400 deg$^2$ available in the UKIDSS Large Area Survey Data Release 8 resolve M giants through a volume four times larger than that of the entire Two Micron All Sky Survey. Combining near-infrared photometry with optical photometry and proper motions from the Sloan Digital Sky Survey yield… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1310.7565v2-abstract-full').style.display = 'inline'; document.getElementById('1310.7565v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1310.7565v2-abstract-full" style="display: none;"> We present a new catalog of 404 M giant candidates found in the UKIRT Infrared Deep Sky Survey (UKIDSS). The 2,400 deg$^2$ available in the UKIDSS Large Area Survey Data Release 8 resolve M giants through a volume four times larger than that of the entire Two Micron All Sky Survey. Combining near-infrared photometry with optical photometry and proper motions from the Sloan Digital Sky Survey yields an M giant candidate catalog with less M dwarf and quasar contamination than previous searches for similarly distant M giants. Extensive follow-up spectroscopy of this sample will yield the first map of our Galaxy's outermost reaches over a large area of sky. Our initial spectroscopic follow-up of $\sim$ 30 bright candidates yielded the positive identification of five M giants at distances $\sim 20-90$ kpc. Each of these confirmed M giants have positions and velocities consistent with the Sagittarius stream. The fainter M giant candidates in our sample have estimated photometric distances $\sim 200$ kpc (assuming $[Fe/H]$ = 0.0), but require further spectroscopic verification. The photometric distance estimates extend beyond the Milky Way's virial radius, and increase by $\sim 50\%$ for each 0.5 dex decrease in assumed $[Fe/H]$. Given the number of M giant candidates, initial selection efficiency, and volume surveyed, we loosely estimate that at least one additional Sagittarius-like accretion event could have contributed to the hierarchical build-up of the Milky Way's outer halo. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1310.7565v2-abstract-full').style.display = 'none'; document.getElementById('1310.7565v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 January, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 October, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 11 figures, emulateapj format. Accepted by AJ</span> </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=West%2C+A&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=West%2C+A&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=West%2C+A&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=West%2C+A&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=West%2C+A&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> </ul> </nav> <div class="is-hidden-tablet">  <span class="help" style="display: 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