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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Besla%2C+G&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Besla%2C+G&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Besla%2C+G&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Besla%2C+G&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.13152">arXiv:2501.13152</a> <span> [<a href="https://arxiv.org/pdf/2501.13152">pdf</a>, <a href="https://arxiv.org/format/2501.13152">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/0.3847/1538-4357/ada24f">0.3847/1538-4357/ada24f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Hubble Space Telescope Survey of M31 Satellite Galaxies IV. Survey Overview and Lifetime Star Formation Histories </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Savino%2C+A">A. Savino</a>, <a href="/search/astro-ph?searchtype=author&query=Weisz%2C+D+R">D. R. Weisz</a>, <a href="/search/astro-ph?searchtype=author&query=Dolphin%2C+A+E">A. E. Dolphin</a>, <a href="/search/astro-ph?searchtype=author&query=Durbin%2C+M+J">M. J. Durbin</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">N. Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Wetzel%2C+A">A. Wetzel</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+J">J. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">G. Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Boylan-Kolchin%2C+M">M. Boylan-Kolchin</a>, <a href="/search/astro-ph?searchtype=author&query=Brown%2C+T+M">T. M. Brown</a>, <a href="/search/astro-ph?searchtype=author&query=Bullock%2C+J+S">J. S. Bullock</a>, <a href="/search/astro-ph?searchtype=author&query=Cole%2C+A+A">A. A. Cole</a>, <a href="/search/astro-ph?searchtype=author&query=Collins%2C+M+L+M">M. L. M. Collins</a>, <a href="/search/astro-ph?searchtype=author&query=Cooper%2C+M+C">M. C. Cooper</a>, <a href="/search/astro-ph?searchtype=author&query=Deason%2C+A+J">A. J. Deason</a>, <a href="/search/astro-ph?searchtype=author&query=Dotter%2C+A+L">A. L. Dotter</a>, <a href="/search/astro-ph?searchtype=author&query=Fardal%2C+M">M. Fardal</a>, <a href="/search/astro-ph?searchtype=author&query=Ferguson%2C+A+M+N">A. M. N. Ferguson</a>, <a href="/search/astro-ph?searchtype=author&query=Fritz%2C+T+K">T. K. Fritz</a>, <a href="/search/astro-ph?searchtype=author&query=Geha%2C+M+C">M. C. Geha</a>, <a href="/search/astro-ph?searchtype=author&query=Gilbert%2C+K+M">K. M. Gilbert</a>, <a href="/search/astro-ph?searchtype=author&query=Guhathakurta%2C+P">P. Guhathakurta</a>, <a href="/search/astro-ph?searchtype=author&query=Ibata%2C+R">R. Ibata</a>, <a href="/search/astro-ph?searchtype=author&query=Irwin%2C+M+J">M. J. Irwin</a>, <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">M. Jeon</a> , et al. (13 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="2501.13152v1-abstract-short" style="display: inline;"> From $>1000$ orbits of HST imaging, we present deep homogeneous resolved star color-magnitude diagrams that reach the oldest main sequence turnoff and uniformly measured star formation histories (SFHs) of 36 dwarf galaxies ($-6 \ge M_V \ge -17$) associated with the M31 halo, and for 10 additional fields in M31, M33, and the Giant Stellar Stream. From our SFHs we find: i) the median stellar age and… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.13152v1-abstract-full').style.display = 'inline'; document.getElementById('2501.13152v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.13152v1-abstract-full" style="display: none;"> From $>1000$ orbits of HST imaging, we present deep homogeneous resolved star color-magnitude diagrams that reach the oldest main sequence turnoff and uniformly measured star formation histories (SFHs) of 36 dwarf galaxies ($-6 \ge M_V \ge -17$) associated with the M31 halo, and for 10 additional fields in M31, M33, and the Giant Stellar Stream. From our SFHs we find: i) the median stellar age and quenching epoch of M31 satellites correlate with galaxy luminosity and galactocentric distance. Satellite luminosity and present-day distance from M31 predict the satellite quenching epoch to within $1.8$ Gyr at all epochs. This tight relationship highlights the fundamental connection between satellite halo mass, environmental history, and star formation duration. ii) There is no difference between the median SFH of galaxies on and off the great plane of Andromeda satellites. iii) $\sim50$\% of our M31 satellites show prominent ancient star formation ($>12$ Gyr ago) followed by delayed quenching ($8-10$ Gyr ago), which is not commonly observed among the MW satellites. iv) A comparison with TNG50 and FIRE-2 simulated satellite dwarfs around M31-like hosts show that some of these trends (dependence of SFH on satellite luminosity) are reproduced in the simulations while others (dependence of SFH on galactocentric distance, presence of the delayed-quenching population) are weaker or absent. We provide all photometric catalogs and SFHs as High-Level Science Products on MAST. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.13152v1-abstract-full').style.display = 'none'; document.getElementById('2501.13152v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication on ApJ. 47 pages, 24 figures, 12 tables. Corresponding HLSP data can be retrieved at: https://archive.stsci.edu/hlsp/m31-satellites</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.14683">arXiv:2411.14683</a> <span> [<a href="https://arxiv.org/pdf/2411.14683">pdf</a>, <a href="https://arxiv.org/format/2411.14683">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Understanding Stellar Mass-Metallicity and Size Relations in Simulated Ultra-Faint Dwarf Galaxies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ko%2C+M">Minsung Ko</a>, <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">Myoungwon Jeon</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Sohn%2C+S+T">Sangmo Tony Sohn</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Richstein%2C+H">Hannah Richstein</a>, <a href="/search/astro-ph?searchtype=author&query=Fu%2C+S+W">Sal Wanying Fu</a>, <a href="/search/astro-ph?searchtype=author&query=Jeong%2C+T+B">Tae Bong Jeong</a>, <a href="/search/astro-ph?searchtype=author&query=Shin%2C+J">Jihye Shin</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="2411.14683v1-abstract-short" style="display: inline;"> Reproducing the physical characteristics of ultra-faint dwarf galaxies (UFDs) in cosmological simulations is challenging, particularly with respect to stellar metallicity and galaxy size. To investigate these difficulties in detail, we conduct high-resolution simulations ($M_{\rm gas} \sim 60 \, M_{\odot}$, $M_{\rm DM} \sim 370 \, M_{\odot}$ ) on six UFD analogs (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.14683v1-abstract-full').style.display = 'inline'; document.getElementById('2411.14683v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.14683v1-abstract-full" style="display: none;"> Reproducing the physical characteristics of ultra-faint dwarf galaxies (UFDs) in cosmological simulations is challenging, particularly with respect to stellar metallicity and galaxy size. To investigate these difficulties in detail, we conduct high-resolution simulations ($M_{\rm gas} \sim 60 \, M_{\odot}$, $M_{\rm DM} \sim 370 \, M_{\odot}$ ) on six UFD analogs ($M_{\rm vir} \sim 10^8 - 10^9 \, M_{\odot}$, $M_{\rm \star} \sim 10^3 - 2.1 \times 10^4 \, M_{\odot}$). Our findings reveal that the stellar properties of UFD analogs are shaped by diverse star-forming environments from multiple progenitor halos in the early Universe. Notably, our UFD analogs exhibit a better match to the observed mass-metallicity relation (MZR), showing higher average metallicity compared to other theoretical models. The metallicity distribution functions (MDFs) of our simulated UFDs lack high-metallicity stars ($[\rm Fe/H] > -2.0$) while containing low-metallicity stars ($[\rm Fe/H] < -4.0$). Excluding these low-metallicity stars, our results align well with the MDFs of observed UFDs. However, forming stars with higher metallicity ($-2.0 \leq [\rm Fe/H]_{\rm max} \leq -1.5$) remains a challenge due to the difficulty of sustaining metal enrichment during their brief star formation period before cosmic reionization. Additionally, our simulations show extended outer structures in UFDs, resulting from dry mergers between progenitor halos. To ensure consistency, we adopt the same fitting method commonly used in observations to derive the half-light radius. We find that this method tends to produce lower values compared to direct calculations and struggles to accurately describe the extended outer structures. To address this, we employ a two-component density profile to obtain structural parameters, finding that it better describes the galaxy shape, including both inner and outer structures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.14683v1-abstract-full').style.display = 'none'; document.getElementById('2411.14683v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">28 pages, 21 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/2410.18182">arXiv:2410.18182</a> <span> [<a href="https://arxiv.org/pdf/2410.18182">pdf</a>, <a href="https://arxiv.org/format/2410.18182">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> </div> <p class="title is-5 mathjax"> Precise Measurements of the LMC Bar's Geometry With Gaia DR3 and a Novel Solution to Crowding Induced Incompleteness in Star Counting </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Rathore%2C+H">Himansh Rathore</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Olsen%2C+K+A+G">Knut A. G. Olsen</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.18182v2-abstract-short" style="display: inline;"> We present new measurements of the two-dimensional (2-D) geometry of the LMC's stellar bar with precise astrometric observations of red clump stars in Gaia DR3. We develop a novel solution to tackle crowding induced incompleteness in Gaia datasets with the Gaia BP-RP color excess. Utilizing the color excess information, we derive a 2-D completeness map of the LMC's disk. We find that incompletenes… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.18182v2-abstract-full').style.display = 'inline'; document.getElementById('2410.18182v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.18182v2-abstract-full" style="display: none;"> We present new measurements of the two-dimensional (2-D) geometry of the LMC's stellar bar with precise astrometric observations of red clump stars in Gaia DR3. We develop a novel solution to tackle crowding induced incompleteness in Gaia datasets with the Gaia BP-RP color excess. Utilizing the color excess information, we derive a 2-D completeness map of the LMC's disk. We find that incompleteness biases the bar measurements and induces large uncertainties. With the completeness-corrected 2-D red clump map, we precisely measure the LMC bar's properties for the first time using Fourier decomposition. The bar radius is $R_{bar} = 2.13^{+0.03}_{-0.04}$ kpc, and its position angle is $121.26^{\circ} \pm 0.21^{\circ}$. The bar's strength as quantified by the Fourier bi-symmetric amplitude is $S_{bar} = 0.27$, indicating that the LMC has a significant bar perturbation. We find the bar has an axis ratio of $0.54 \pm 0.03$, and is offset with respect to the center of the outer disk isophote at R $\approx$ 5 kpc by $0.76 \pm 0.01$ kpc. These LMC bar properties agree with a hydrodynamic model where the SMC has undergone a recent direct collision with the LMC. We compare the LMC's bar properties with other barred galaxies in the local universe, and discover that the LMC is similar to other barred galaxies in terms of bar-galaxy scaling relations. We discuss how our completeness correction framework can be applied to other systems in the Local Group. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.18182v2-abstract-full').style.display = 'none'; document.getElementById('2410.18182v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, accepted to ApJ, updated to the accepted version</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.00114">arXiv:2410.00114</a> <span> [<a href="https://arxiv.org/pdf/2410.00114">pdf</a>, <a href="https://arxiv.org/format/2410.00114">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> The distant Milky Way halo from the Southern hemisphere: Characterization of the LMC-induced dynamical-friction wake </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cavieres%2C+M">Manuel Cavieres</a>, <a href="/search/astro-ph?searchtype=author&query=Chanam%C3%A9%2C+J">Julio Chanam茅</a>, <a href="/search/astro-ph?searchtype=author&query=Navarrete%2C+C">Camila Navarrete</a>, <a href="/search/astro-ph?searchtype=author&query=Ordenes-Brice%C3%B1o%2C+Y">Yasna Ordenes-Brice帽o</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicol谩s Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Hempel%2C+M">Maren Hempel</a>, <a href="/search/astro-ph?searchtype=author&query=Vivas%2C+K">Katherina Vivas</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3mez%2C+F">Facundo G贸mez</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.00114v1-abstract-short" style="display: inline;"> The infall of the LMC into the Milky Way's halo impacts the distribution of stars and dark matter in our Galaxy. Mapping the observational consequences of this encounter can inform us about the properties of both galaxies, details of their interaction, and possibly even distinguish between different dark matter models. N-body simulations predict large-scale density asymmetries in the Galactic halo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.00114v1-abstract-full').style.display = 'inline'; document.getElementById('2410.00114v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.00114v1-abstract-full" style="display: none;"> The infall of the LMC into the Milky Way's halo impacts the distribution of stars and dark matter in our Galaxy. Mapping the observational consequences of this encounter can inform us about the properties of both galaxies, details of their interaction, and possibly even distinguish between different dark matter models. N-body simulations predict large-scale density asymmetries in the Galactic halo both in baryonic and dark matter due to the passage of the LMC, with the overdensity directly trailing its current orbit through the Southern hemisphere known as the wake. Using the VIRCAM and DECam instruments, we collected wide-field deep near-infrared and optical photometry in four fields chosen to cover the region of the sky expected to span most of the predicted density contrast of the wake. We identify more than 400 stars comprising two different tracers, near main sequence turn-off stars and red giants, that map the distant halo between $\sim 60$ - $100$ kpc, and use them to derive stellar halo densities as a function of position in the sky and Galactocentric radius. We detect (1) a break in the radial density profile of halo stars at 70 kpc that has not been seen in halo studies done from the North, and (2) a clear halo overdensity that starts also at 70 kpc and exhibits a density contrast that increases steadily when moving across the sky into the predicted current location of the LMC wake. If identifying this overdensity with the LMC wake, the peak density contrast we measure is more pronounced than in all available models of the LMC infall, which would indicate the need for a more massive LMC and/or with a different orbit than presently favored. Alternatively, contamination from unidentified substructure may be biasing our detections, so wider-area surveys with similar depth would be needed for confirmation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.00114v1-abstract-full').style.display = 'none'; document.getElementById('2410.00114v1-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 10 figures, submitted to ApJ, comments are welcome!</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.02233">arXiv:2409.02233</a> <span> [<a href="https://arxiv.org/pdf/2409.02233">pdf</a>, <a href="https://arxiv.org/format/2409.02233">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> A Physically Motivated Framework to Compare Merger Timescales of Isolated Low- and High-Mass Galaxy Pairs Across Cosmic Time </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chamberlain%2C+K">Katie Chamberlain</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Torrey%2C+P">Paul Torrey</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez-Gomez%2C+V">Vicente Rodriguez-Gomez</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.02233v1-abstract-short" style="display: inline;"> The merger timescales of isolated low-mass pairs ($\rm 10^8<M_*<5\times10^9\,M_{\odot}$) on cosmologically motivated orbits have not yet been studied in detail, though isolated high-mass pairs ($\rm 5\times10^9<M_*<10^{11}\,M_{\odot}$) have been studied extensively. It is common to apply the same separation criteria and expected merger timescales of high-mass pairs to low-mass systems, however, it… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.02233v1-abstract-full').style.display = 'inline'; document.getElementById('2409.02233v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.02233v1-abstract-full" style="display: none;"> The merger timescales of isolated low-mass pairs ($\rm 10^8<M_*<5\times10^9\,M_{\odot}$) on cosmologically motivated orbits have not yet been studied in detail, though isolated high-mass pairs ($\rm 5\times10^9<M_*<10^{11}\,M_{\odot}$) have been studied extensively. It is common to apply the same separation criteria and expected merger timescales of high-mass pairs to low-mass systems, however, it is unclear if their merger timescales are similar, or if they evolve similarly with redshift. We use the Illustris TNG100 simulation to quantify the merger timescales of isolated low-mass and high-mass major pairs as a function of cosmic time, and explore how different selection criteria impact the mass and redshift dependence of merger timescales. In particular, we present a physically-motivated framework for selecting pairs via a scaled separation criteria, wherein pair separations are scaled by the virial radius of the primary's FoF group halo ($r_{\mathrm{sep}}< 1 R_{vir}$). Applying these scaled separation criteria yields equivalent merger timescales for both mass scales at all redshifts. Alternatively, static physical separation selections applied equivalently to all galaxy pairs at all redshifts leads to a difference in merger rates of up to $\rm \sim 1\, Gyr$ between low- and high-mass pairs, particularly for $\rm r_{sep}<150\, kpc$. As a result, applying the same merger timescales to physical separation-selected pairs will lead to a bias that systematically over-predicts low-mass galaxy merger rates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.02233v1-abstract-full').style.display = 'none'; document.getElementById('2409.02233v1-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 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/2408.10358">arXiv:2408.10358</a> <span> [<a href="https://arxiv.org/pdf/2408.10358">pdf</a>, <a href="https://arxiv.org/format/2408.10358">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> The All-Sky Impact of the LMC on the Milky Way Circumgalactic Medium </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Carr%2C+C">Christopher Carr</a>, <a href="/search/astro-ph?searchtype=author&query=Bryan%2C+G+L">Greg L. Bryan</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicol谩s Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Setton%2C+D+J">David J. Setton</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+K+V">Kathryn V. Johnston</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.10358v1-abstract-short" style="display: inline;"> The first infall of the LMC into the Milky Way (MW) represents a large and recent disruption to the MW circumgalactic medium (CGM). In this work, we use idealized, hydrodynamical simulations of a MW-like CGM embedded in a live dark matter halo with an infalling LMC-like satellite initialized with its own CGM to understand how the encounter is shaping the global physical and kinematic properties of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10358v1-abstract-full').style.display = 'inline'; document.getElementById('2408.10358v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.10358v1-abstract-full" style="display: none;"> The first infall of the LMC into the Milky Way (MW) represents a large and recent disruption to the MW circumgalactic medium (CGM). In this work, we use idealized, hydrodynamical simulations of a MW-like CGM embedded in a live dark matter halo with an infalling LMC-like satellite initialized with its own CGM to understand how the encounter is shaping the global physical and kinematic properties of the MW CGM. First, we find that the LMC sources order-unity enhancements in MW CGM density, temperature, and pressure from a $\mathcal{M} \approx 2$ shock from the supersonic CGM-CGM collision, extending from the LMC to beyond $\sim R_{\rm 200, MW}$, enhancing column densities, X-ray brightness, the thermal Sunyaev-Zeldovich (tSZ) distortion, and potentially synchrotron emission from cosmic rays over large angular scales across the Southern Hemisphere. Second, the MW's reflex motion relative to its outer halo produces a dipole in CGM radial velocities, with $v_{\rm R} \pm 30-50$ km/s at $R > 50$ kpc in the Northern/Southern hemispheres respectively, consistent with measurements in the stellar halo. Finally, ram pressure strips most of the LMC CGM gas by the present day, leaving $\sim 10^{8-9} M_{\odot}$ of warm, ionized gas along the past orbit of the LMC moving at high radial and/or tangential velocities $\sim 50-100$ kpc from the MW. Massive satellites like the LMC leave their mark on the CGM structure of their host galaxies, and signatures from this interaction may manifest in key all-sky observables of the CGM of the MW and other massive galaxies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10358v1-abstract-full').style.display = 'none'; document.getElementById('2408.10358v1-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to ApJ. 22 pages, 15 Figures. Comments welcomed</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.06415">arXiv:2408.06415</a> <span> [<a href="https://arxiv.org/pdf/2408.06415">pdf</a>, <a href="https://arxiv.org/format/2408.06415">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ad9b89">10.3847/1538-4357/ad9b89 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Segue 2 Recently Collided with the Cetus-Palca Stream: New Opportunities to Constrain Dark Matter in an Ultra-Faint Dwarf </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Foote%2C+H+R">Hayden R. Foote</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicol谩s Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Thomas%2C+G+F">Guillaume F. Thomas</a>, <a href="/search/astro-ph?searchtype=author&query=Bonaca%2C+A">Ana Bonaca</a>, <a href="/search/astro-ph?searchtype=author&query=Price-Whelan%2C+A+M">Adrian M. Price-Whelan</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+A+H+G">Annika H. G. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Zaritsky%2C+D">Dennis Zaritsky</a>, <a href="/search/astro-ph?searchtype=author&query=Conroy%2C+C">Charlie Conroy</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.06415v2-abstract-short" style="display: inline;"> Stellar streams in the Milky Way are promising detectors of low-mass dark matter (DM) subhalos predicted by $螞$CDM. Passing subhalos induce perturbations in streams that indicate the presence of the subhalos. Understanding how known DM-dominated satellites impact streams is a crucial step towards using stream perturbations to constrain the properties of dark perturbers. Here, we cross-match a \tex… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.06415v2-abstract-full').style.display = 'inline'; document.getElementById('2408.06415v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.06415v2-abstract-full" style="display: none;"> Stellar streams in the Milky Way are promising detectors of low-mass dark matter (DM) subhalos predicted by $螞$CDM. Passing subhalos induce perturbations in streams that indicate the presence of the subhalos. Understanding how known DM-dominated satellites impact streams is a crucial step towards using stream perturbations to constrain the properties of dark perturbers. Here, we cross-match a \textit{Gaia} EDR3 and SEGUE member catalog of the Cetus-Palca stream (CPS) with H3 for additional radial velocity measurements and fit the orbit of the CPS using this 6-D data. We demonstrate for the first time that the ultra-faint dwarf Segue 2 had a recent (77$\pm$5 Myr ago) close flyby (within the stream's 2$蟽$ width) with the CPS. This interaction enables constraints on Segue 2's mass and density profile at larger radii ($\mathcal{O}(1)$ kpc) than are probed by its stars ($\mathcal{O}(10)$ pc). While Segue 2 is not expected to strongly affect the portion of the stream covered by our 6-D data, we predict that if Segue 2's mass within $\sim 6$ kpc is $5\times 10^9\,M_\odot$, the CPS's velocity dispersion will be $\sim 40$ km s$^{-1}$ larger at $蠁_1>20^\circ$ than at $蠁_1<0^\circ$. If no such heating is detected, Segue 2's mass cannot exceed $10^9\,M_\odot$ within $\sim 6$ kpc. The proper motion distribution of the CPS near the impact site is mildly sensitive to the shape of Segue 2's density profile. This study presents a critical test for frameworks designed to constrain properties of dark subhalos from stream perturbations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.06415v2-abstract-full').style.display = 'none'; document.getElementById('2408.06415v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">33 pages, 14 figures, 6 tables. Updated for consistency with published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ, 979, 171 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.13876">arXiv:2407.13876</a> <span> [<a href="https://arxiv.org/pdf/2407.13876">pdf</a>, <a href="https://arxiv.org/format/2407.13876">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Unveiling the purely young star formation history of the SMC's northeastern shell from colour-magnitude diagram fitting </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sakowska%2C+J+D">Joanna D. Sakowska</a>, <a href="/search/astro-ph?searchtype=author&query=No%C3%ABl%2C+N+E+D">Noelia E. D. No毛l</a>, <a href="/search/astro-ph?searchtype=author&query=Ruiz-Lara%2C+T">Tom谩s Ruiz-Lara</a>, <a href="/search/astro-ph?searchtype=author&query=Gallart%2C+C">Carme Gallart</a>, <a href="/search/astro-ph?searchtype=author&query=Massana%2C+P">Pol Massana</a>, <a href="/search/astro-ph?searchtype=author&query=Nidever%2C+D+L">David L. Nidever</a>, <a href="/search/astro-ph?searchtype=author&query=Cassisi%2C+S">Santi Cassisi</a>, <a href="/search/astro-ph?searchtype=author&query=Correa-Amaro%2C+P">Patricio Correa-Amaro</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Erkal%2C+D">Denis Erkal</a>, <a href="/search/astro-ph?searchtype=author&query=Mart%C3%ADnez-Delgado%2C+D">David Mart铆nez-Delgado</a>, <a href="/search/astro-ph?searchtype=author&query=Monelli%2C+M">Matteo Monelli</a>, <a href="/search/astro-ph?searchtype=author&query=Olsen%2C+K+A+G">Knut A. G. Olsen</a>, <a href="/search/astro-ph?searchtype=author&query=Stringfellow%2C+G+S">Guy S. Stringfellow</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.13876v1-abstract-short" style="display: inline;"> We obtain a quantitative star formation history (SFH) of a shell-like structure ('shell') located in the northeastern part of the Small Magellanic Cloud (SMC). We use the Survey of the MAgellanic Stellar History (SMASH) to derive colour-magnitude diagrams (CMDs), reaching below the oldest main-sequence turnoff, from which we compute the SFHs with CMD fitting techniques. We present, for the first t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.13876v1-abstract-full').style.display = 'inline'; document.getElementById('2407.13876v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.13876v1-abstract-full" style="display: none;"> We obtain a quantitative star formation history (SFH) of a shell-like structure ('shell') located in the northeastern part of the Small Magellanic Cloud (SMC). We use the Survey of the MAgellanic Stellar History (SMASH) to derive colour-magnitude diagrams (CMDs), reaching below the oldest main-sequence turnoff, from which we compute the SFHs with CMD fitting techniques. We present, for the first time, a novel technique that uses red clump (RC) stars from the CMDs to assess and account for the SMC's line-of-sight depth effect present during the SFH derivation. We find that accounting for this effect recovers a more accurate SFH. We quantify a 7 kpc line-of-sight depth present in the CMDs, in good agreement with depth estimates from RC stars in the northeastern SMC. By isolating the stellar content of the northeastern shell and incorporating the line-of-sight depth into our calculations, we obtain an unprecedentedly detailed SFH. We find that the northeastern shell is primarily composed of stars younger than 500 Myrs, with significant star formation enhancements around 250 Myr and 450 Myr. These young stars are the main contributors to the shell's structure. We show synchronicity between the northeastern shell's SFH with the Large Magellanic Cloud's (LMC) northern arm, which we attribute to the interaction history of the SMC with the LMC and the Milky Way (MW) over the past 500 Myr. Our results highlight the complex interplay of ram pressure stripping and the influence of the MW's circumgalactic medium in shaping the SMC's northeastern shell. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.13876v1-abstract-full').style.display = 'none'; document.getElementById('2407.13876v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 13 figures. Accepted to MNRAS for publication</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.07769">arXiv:2407.07769</a> <span> [<a href="https://arxiv.org/pdf/2407.07769">pdf</a>, <a href="https://arxiv.org/format/2407.07769">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ad571c">10.3847/1538-4357/ad571c <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> HSTPROMO Internal Proper Motion Kinematics of Dwarf Spheroidal Galaxies: I. Velocity Anisotropy and Dark Matter Cusp Slope of Draco </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Vitral%2C+E">Eduardo Vitral</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Sohn%2C+S+T">Sangmo Tony Sohn</a>, <a href="/search/astro-ph?searchtype=author&query=Libralato%2C+M">Mattia Libralato</a>, <a href="/search/astro-ph?searchtype=author&query=del+Pino%2C+A">Andr茅s del Pino</a>, <a href="/search/astro-ph?searchtype=author&query=Watkins%2C+L+L">Laura L. Watkins</a>, <a href="/search/astro-ph?searchtype=author&query=Bellini%2C+A">Andrea Bellini</a>, <a href="/search/astro-ph?searchtype=author&query=Walker%2C+M+G">Matthew G. Walker</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Pawlowski%2C+M+S">Marcel S. Pawlowski</a>, <a href="/search/astro-ph?searchtype=author&query=Mamon%2C+G+A">Gary A. Mamon</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.07769v1-abstract-short" style="display: inline;"> We analyze four epochs of HST imaging over 18 years for the Draco dwarf spheroidal galaxy. We measure precise proper motions (PMs) for hundreds of stars and combine these with existing line-of-sight (LOS) velocities. This provides the first radially-resolved 3D velocity dispersion profiles for any dwarf galaxy. These constrain the intrinsic velocity anisotropy and resolve the mass-anisotropy degen… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.07769v1-abstract-full').style.display = 'inline'; document.getElementById('2407.07769v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.07769v1-abstract-full" style="display: none;"> We analyze four epochs of HST imaging over 18 years for the Draco dwarf spheroidal galaxy. We measure precise proper motions (PMs) for hundreds of stars and combine these with existing line-of-sight (LOS) velocities. This provides the first radially-resolved 3D velocity dispersion profiles for any dwarf galaxy. These constrain the intrinsic velocity anisotropy and resolve the mass-anisotropy degeneracy. We solve the Jeans equations in oblate axisymmetric geometry to infer the mass profile. We find the velocity dispersion to be radially anisotropic along the symmetry axis and tangentially anisotropic in the equatorial plane, with a globally-averaged value $\overline{尾_{\mathrm B}}=-0.20^{+ 0.28}_{- 0.53}$, (where $1 - 尾_{\mathrm B} \equiv \langle v_{\mathrm{ tan}}^2 \rangle / \langle v_{\mathrm{ rad}}^2 \rangle$ in 3D). The logarithmic dark matter (DM) density slope over the observed radial range, $螕_{\mathrm{ dark}}$, is $-0.83^{+ 0.32}_{- 0.37}$, consistent with the inner cusp predicted in $螞$CDM cosmology. As expected given Draco's low mass and ancient star formation history, it does not appear to have been dissolved by baryonic processes. We rule out cores larger than 487, 717, 942 pc at respective 1-, 2-, 3-$蟽$ confidence, thus imposing important constraints on the self-interacting DM cross-section. Spherical models yield biased estimates for both the velocity anisotropy and the inferred slope. The circular velocity at our outermost data point (900 pc) is $24.19^{+ 6.31}_{- 2.97} \ \mathrm{km~s^{-1}}s$. We infer a dynamical distance of $75.37^{+ 4.73}_{- 4.00}$ kpc, and show that Draco has a modest LOS rotation, with $\left<v / 蟽\right> = 0.22 \pm 0.09$. Our results provide a new stringent test of the so-called `cusp-core' problem that can be readily extended to other dwarfs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.07769v1-abstract-full').style.display = 'none'; document.getElementById('2407.07769v1-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">35 pages, 18 figures, 3 Tables. Accepted for publication in ApJ. Journal version has better readability. Data is available at Zenodo: https://zenodo.org/records/11111113</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, 970:1 (26pp), 2024 July 20 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.08731">arXiv:2402.08731</a> <span> [<a href="https://arxiv.org/pdf/2402.08731">pdf</a>, <a href="https://arxiv.org/format/2402.08731">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Deep Hubble Space Telescope Photometry of LMC and Milky Way Ultra-Faint Dwarfs: A careful look into the magnitude-size relation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Richstein%2C+H">Hannah Richstein</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Simon%2C+J+D">Joshua D. Simon</a>, <a href="/search/astro-ph?searchtype=author&query=Garling%2C+C+T">Christopher T. Garling</a>, <a href="/search/astro-ph?searchtype=author&query=Wetzel%2C+A">Andrew Wetzel</a>, <a href="/search/astro-ph?searchtype=author&query=Warfield%2C+J+T">Jack T. Warfield</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">Myoungwon Jeon</a>, <a href="/search/astro-ph?searchtype=author&query=Rose%2C+J+C">Jonah C. Rose</a>, <a href="/search/astro-ph?searchtype=author&query=Torrey%2C+P">Paul Torrey</a>, <a href="/search/astro-ph?searchtype=author&query=Engelhardt%2C+A+C">Anna Claire Engelhardt</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Geha%2C+M">Marla Geha</a>, <a href="/search/astro-ph?searchtype=author&query=Guhathakurta%2C+P">Puragra Guhathakurta</a>, <a href="/search/astro-ph?searchtype=author&query=Kirby%2C+E+N">Evan N. Kirby</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Sacchi%2C+E">Elena Sacchi</a>, <a href="/search/astro-ph?searchtype=author&query=Sohn%2C+S+T">Sangmo Tony Sohn</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="2402.08731v1-abstract-short" style="display: inline;"> We present deep Hubble Space Telescope (HST) photometry of ten targets from Treasury Program GO-14734, including six confirmed ultra-faint dwarf galaxies (UFDs), three UFD candidates, and one likely globular cluster. Six of these targets are satellites of, or have interacted with, the Large Magellanic Cloud (LMC). We determine their structural parameters using a maximum-likelihood technique. Using… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.08731v1-abstract-full').style.display = 'inline'; document.getElementById('2402.08731v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.08731v1-abstract-full" style="display: none;"> We present deep Hubble Space Telescope (HST) photometry of ten targets from Treasury Program GO-14734, including six confirmed ultra-faint dwarf galaxies (UFDs), three UFD candidates, and one likely globular cluster. Six of these targets are satellites of, or have interacted with, the Large Magellanic Cloud (LMC). We determine their structural parameters using a maximum-likelihood technique. Using our newly derived half-light radius ($r_h$) and $V$-band magnitude ($M_V$) values in addition to literature values for other UFDs, we find that UFDs associated with the LMC do not show any systematic differences from Milky Way UFDs in the magnitude-size plane. Additionally, we convert simulated UFD properties from the literature into the $M_V-r_h$ observational space to examine the abilities of current dark matter (DM) and baryonic simulations to reproduce observed UFDs. Some of these simulations adopt alternative DM models, thus allowing us to also explore whether the $M_V-r_h$ plane could be used to constrain the nature of DM. We find no differences in the magnitude-size plane between UFDs simulated with cold, warm, and self-interacting dark matter, but note that the sample of UFDs simulated with alternative DM models is quite limited at present. As more deep, wide-field survey data become available, we will have further opportunities to discover and characterize these ultra-faint stellar systems and the greater low surface-brightness universe. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.08731v1-abstract-full').style.display = 'none'; document.getElementById('2402.08731v1-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 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">42 pages, 13 figures, 13 tables, 2 appendices; Submitted to AAS Journals</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.09276">arXiv:2312.09276</a> <span> [<a href="https://arxiv.org/pdf/2312.09276">pdf</a>, <a href="https://arxiv.org/format/2312.09276">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Proper Motions and Orbits of Distant Local Group Dwarf Galaxies from a combination of Gaia and Hubble Data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bennet%2C+P">Paul Bennet</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Sohn%2C+S+T">Sangmo Tony Sohn</a>, <a href="/search/astro-ph?searchtype=author&query=del+Pino%2C+A">Andres del Pino</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Libralato%2C+M">Mattia Libralato</a>, <a href="/search/astro-ph?searchtype=author&query=Watkins%2C+L+L">Laura L. Watkins</a>, <a href="/search/astro-ph?searchtype=author&query=Aparicio%2C+A">Antonio Aparicio</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Gallart%2C+C">Carme Gallart</a>, <a href="/search/astro-ph?searchtype=author&query=Fardal%2C+M+A">Mark A. Fardal</a>, <a href="/search/astro-ph?searchtype=author&query=Monelli%2C+M">Matteo Monelli</a>, <a href="/search/astro-ph?searchtype=author&query=Sacchi%2C+E">Elena Sacchi</a>, <a href="/search/astro-ph?searchtype=author&query=Tollerud%2C+E">Erik Tollerud</a>, <a href="/search/astro-ph?searchtype=author&query=Weisz%2C+D+R">Daniel R. Weisz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.09276v1-abstract-short" style="display: inline;"> We have determined the proper motions (PMs) of 12 dwarf galaxies in the Local Group (LG), ranging from the outer Milky Way (MW) halo to the edge of the LG. We used HST as the first and Gaia as the second epoch using the GaiaHub software. For Leo A and Sag DIG we also used multi-epoch HST measurements relative to background galaxies. Orbital histories derived using these PMs show that two-thirds of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.09276v1-abstract-full').style.display = 'inline'; document.getElementById('2312.09276v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.09276v1-abstract-full" style="display: none;"> We have determined the proper motions (PMs) of 12 dwarf galaxies in the Local Group (LG), ranging from the outer Milky Way (MW) halo to the edge of the LG. We used HST as the first and Gaia as the second epoch using the GaiaHub software. For Leo A and Sag DIG we also used multi-epoch HST measurements relative to background galaxies. Orbital histories derived using these PMs show that two-thirds of the galaxies in our sample are on first infall with $>$90\% certainty. The observed star formation histories (SFHs) of these first-infall dwarfs are generally consistent with infalling dwarfs in simulations. The remaining four galaxies have crossed the virial radius of either the MW or M31. When we compare their star formation (SF) and orbital histories we find tentative agreement between the inferred pattern of SF with the timing of dynamical events in the orbital histories. For Leo~I, SF activity rises as the dwarf crosses the MW's virial radius, culminating in a burst of SF shortly before pericenter ($\approx1.7$~Gyr ago). The SF then declines after pericenter, but with some smaller bursts before its recent quenching ($\approx0.3$~Gyr ago). This shows that even small dwarfs like Leo~I can hold on to gas reservoirs and avoid quenching for several Gyrs after falling into their host, which is longer than generally found in simulations. Leo~II, NGC~6822, and IC~10 are also qualitatively consistent with this SF pattern in relation to their orbit, but more tentatively due to larger uncertainties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.09276v1-abstract-full').style.display = 'none'; document.getElementById('2312.09276v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">27 pages, 9 Figures, 8 Tables, Submitted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.02152">arXiv:2311.02152</a> <span> [<a href="https://arxiv.org/pdf/2311.02152">pdf</a>, <a href="https://arxiv.org/format/2311.02152">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Gas and star formation in satellites of Milky Way analogs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Jones%2C+M+G">Michael G. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Sand%2C+D+J">David J. Sand</a>, <a href="/search/astro-ph?searchtype=author&query=Karunakaran%2C+A">Ananthan Karunakaran</a>, <a href="/search/astro-ph?searchtype=author&query=Spekkens%2C+K">Kristine Spekkens</a>, <a href="/search/astro-ph?searchtype=author&query=Oman%2C+K+A">Kyle A. Oman</a>, <a href="/search/astro-ph?searchtype=author&query=Bennet%2C+P">Paul Bennet</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Crnojevic%2C+D">Denija Crnojevic</a>, <a href="/search/astro-ph?searchtype=author&query=Cuillandre%2C+J">Jean-Charles Cuillandre</a>, <a href="/search/astro-ph?searchtype=author&query=Fielder%2C+C+E">Catherine E. Fielder</a>, <a href="/search/astro-ph?searchtype=author&query=Gwyn%2C+S">Stephen Gwyn</a>, <a href="/search/astro-ph?searchtype=author&query=Mutlu-Pakdil%2C+B">Burcin Mutlu-Pakdil</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="2311.02152v2-abstract-short" style="display: inline;"> We have imaged the entirety of eight (plus one partial) Milky Way-like satellite systems, a total of 42 (45) satellites, from the Satellites Around Galactic Analogs (SAGA) II catalog in both H$伪$ and HI with the Canada-France-Hawaii Telescope and the Jansky Very Large Array. In these eight systems we have identified four cases where a satellite appears to be currently undergoing ram pressure strip… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.02152v2-abstract-full').style.display = 'inline'; document.getElementById('2311.02152v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.02152v2-abstract-full" style="display: none;"> We have imaged the entirety of eight (plus one partial) Milky Way-like satellite systems, a total of 42 (45) satellites, from the Satellites Around Galactic Analogs (SAGA) II catalog in both H$伪$ and HI with the Canada-France-Hawaii Telescope and the Jansky Very Large Array. In these eight systems we have identified four cases where a satellite appears to be currently undergoing ram pressure stripping (RPS) as its HI gas collides with the circumgalactic medium (CGM) of its host. We also see a clear suppression of gas fraction ($M_\mathrm{HI}/M_\ast$) with decreasing (projected) satellite--host separation; to our knowledge, the first time this has been observed in a sample of Milky Way-like systems. Comparisons to the Auriga, APOSTLE, and TNG50 cosmological zoom-in simulations show consistent global behavior, but they systematically under-predict gas fractions across all satellites by roughly 0.5 dex. Using a simplistic RPS model we estimate the average peak CGM density that satellites in these systems have encountered to be $\log 蟻_\mathrm{cgm}/\mathrm{g\,cm^{-3}} \approx -27.3$. Furthermore, we see tentative evidence that these satellites are following a specific star formation rate-to-gas fraction relation that is distinct from field galaxies. Finally, we detect one new gas-rich satellite in the UGC903 system with an optical size and surface brightness meeting the standard criteria to be considered an ultra-diffuse galaxy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.02152v2-abstract-full').style.display = 'none'; document.getElementById('2311.02152v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted 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/2309.13228">arXiv:2309.13228</a> <span> [<a href="https://arxiv.org/pdf/2309.13228">pdf</a>, <a href="https://arxiv.org/format/2309.13228">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> A physically motivated framework to compare pair fractions of isolated low and high mass galaxies across cosmic time </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chamberlain%2C+K">Katie Chamberlain</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez-Gomez%2C+V">Vicente Rodriguez-Gomez</a>, <a href="/search/astro-ph?searchtype=author&query=Torrey%2C+P">Paul Torrey</a>, <a href="/search/astro-ph?searchtype=author&query=Martin%2C+G">Garreth Martin</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+K">Kelsey Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Patton%2C+D">David Patton</a>, <a href="/search/astro-ph?searchtype=author&query=Pearson%2C+S">Sarah Pearson</a>, <a href="/search/astro-ph?searchtype=author&query=Privon%2C+G">George Privon</a>, <a href="/search/astro-ph?searchtype=author&query=Stierwalt%2C+S">Sabrina Stierwalt</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2309.13228v2-abstract-short" style="display: inline;"> Low mass galaxy pair fractions are understudied, and it is unclear whether low mass pair fractions evolve in the same way as more massive systems over cosmic time. In the era of JWST, Roman, and Rubin, selecting galaxy pairs in a self-consistent way will be critical to connect observed pair fractions to cosmological merger rates across all mass scales and redshifts. Utilizing the Illustris TNG100… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.13228v2-abstract-full').style.display = 'inline'; document.getElementById('2309.13228v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.13228v2-abstract-full" style="display: none;"> Low mass galaxy pair fractions are understudied, and it is unclear whether low mass pair fractions evolve in the same way as more massive systems over cosmic time. In the era of JWST, Roman, and Rubin, selecting galaxy pairs in a self-consistent way will be critical to connect observed pair fractions to cosmological merger rates across all mass scales and redshifts. Utilizing the Illustris TNG100 simulation, we create a sample of physically associated low mass ($\rm 10^8<M_*<5\times10^9\,M_\odot$) and high mass ($\rm 5\times10^9<M_*<10^{11}\,M_\odot$) pairs between $z=0$ and $4.2$. The low mass pair fraction increases from $z=0$ to $2.5$, while the high mass pair fraction peaks at $z=0$ and is constant or slightly decreasing at $z>1$. At $z=0$, the low mass major (1:4 mass ratio) pair fraction is 4$\times$ lower than high mass pairs, consistent with findings for cosmological merger rates. We show that separation limits that vary with the mass and redshift of the system, such as scaling by the virial radius of the host halo ($r_{\mathrm{sep}}< 1 R_{\rm vir}$), are critical for recovering pair fraction differences between low mass and high mass systems. Alternatively, static physical separation limits applied equivalently to all galaxy pairs do not recover the differences between low and high mass pair fractions, even up to separations of $300$ kpc. Finally, we place isolated mass-analogs of Local Group galaxy pairs, i.e., Milky Way (MW)--M31, MW--LMC, LMC--SMC, in a cosmological context, showing that isolated analogs of LMC--SMC-mass pairs and low-separation ($<50$ kpc) MW--LMC-mass pairs are $2-3\times$ more common at $z\gtrsim2-3$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.13228v2-abstract-full').style.display = 'none'; document.getElementById('2309.13228v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 5 figures, accepted for publication in ApJ, updated Feb 2024 to reflect accepted version</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.10963">arXiv:2308.10963</a> <span> [<a href="https://arxiv.org/pdf/2308.10963">pdf</a>, <a href="https://arxiv.org/format/2308.10963">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> The Large Magellanic Cloud's $\sim30$ Kiloparsec Bow Shock and its Impact on the Circumgalactic Medium </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Setton%2C+D+J">David J. Setton</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Hummels%2C+C">Cameron Hummels</a>, <a href="/search/astro-ph?searchtype=author&query=Zheng%2C+Y">Yong Zheng</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+E">Evan 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="2308.10963v2-abstract-short" style="display: inline;"> The interaction between the supersonic motion of the Large Magellanic Cloud (LMC) and the Circumgalactic Medium (CGM) is expected to result in a bow shock that leads the LMC's gaseous disk. In this letter, we use hydrodynamic simulations of the LMC's recent infall to predict the extent of this shock and its effect on the Milky Way's (MW) CGM. The simulations clearly predict the existence of an asy… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10963v2-abstract-full').style.display = 'inline'; document.getElementById('2308.10963v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.10963v2-abstract-full" style="display: none;"> The interaction between the supersonic motion of the Large Magellanic Cloud (LMC) and the Circumgalactic Medium (CGM) is expected to result in a bow shock that leads the LMC's gaseous disk. In this letter, we use hydrodynamic simulations of the LMC's recent infall to predict the extent of this shock and its effect on the Milky Way's (MW) CGM. The simulations clearly predict the existence of an asymmetric shock with a present day stand-off radius of $\sim6.7$ kpc and a transverse diameter of $\sim30$ kpc. Over the past 500 Myr, $\sim8\%$ of the MW's CGM in the southern hemisphere should have interacted with the shock front. This interaction may have had the effect of smoothing over inhomogeneities and increasing mixing in the MW CGM. We find observational evidence of the existence of the bow shock in recent $H伪$ maps of the LMC, providing a potential explanation for the envelope of ionized gas surrounding the LMC. Furthermore, the interaction of the bow shock with the MW CGM may also explain observations of ionized gas surrounding the Magellanic Stream. Using recent orbital histories of MW satellites, we find that many satellites have likely interacted with the LMC shock. Additionally, the dwarf galaxy Ret2 is currently sitting inside the shock, which may impact the interpretation of reported gamma ray excess in Ret2. This work highlights bow shocks associated with infalling satellites are an under-explored, yet potentially very important dynamical mixing process in the circumgalactic and intracluster media. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10963v2-abstract-full').style.display = 'none'; document.getElementById('2308.10963v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Re-uploaded after acceptance to ApJ Letters. 5 figures and 1 table. Comments welcome!</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.00053">arXiv:2307.00053</a> <span> [<a href="https://arxiv.org/pdf/2307.00053">pdf</a>, <a href="https://arxiv.org/format/2307.00053">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ace533">10.3847/1538-4357/ace533 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Structure, Kinematics, and Observability of the Large Magellanic Cloud's Dynamical Friction Wake in Cold vs. Fuzzy Dark Matter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Foote%2C+H+R">Hayden R. Foote</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Mocz%2C+P">Philip Mocz</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicol谩s Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Lancaster%2C+L">Lachlan Lancaster</a>, <a href="/search/astro-ph?searchtype=author&query=Sparre%2C+M">Martin Sparre</a>, <a href="/search/astro-ph?searchtype=author&query=Cunningham%2C+E+C">Emily C. Cunningham</a>, <a href="/search/astro-ph?searchtype=author&query=Vogelsberger%2C+M">Mark Vogelsberger</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3mez%2C+F+A">Facundo A. G贸mez</a>, <a href="/search/astro-ph?searchtype=author&query=Laporte%2C+C+F+P">Chervin F. P. Laporte</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="2307.00053v2-abstract-short" style="display: inline;"> The Large Magellanic Cloud (LMC) will induce a dynamical friction (DF) wake on infall to the Milky Way (MW). The MW's stellar halo will respond to the gravity of the LMC and the dark matter (DM) wake, forming a stellar counterpart to the DM wake. This provides a novel opportunity to constrain the properties of the DM particle. We present a suite of high-resolution, windtunnel-style simulations of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.00053v2-abstract-full').style.display = 'inline'; document.getElementById('2307.00053v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.00053v2-abstract-full" style="display: none;"> The Large Magellanic Cloud (LMC) will induce a dynamical friction (DF) wake on infall to the Milky Way (MW). The MW's stellar halo will respond to the gravity of the LMC and the dark matter (DM) wake, forming a stellar counterpart to the DM wake. This provides a novel opportunity to constrain the properties of the DM particle. We present a suite of high-resolution, windtunnel-style simulations of the LMC's DF wake that compare the structure, kinematics, and stellar tracer response of the DM wake in cold DM (CDM), with and without self-gravity, vs. fuzzy DM (FDM) with $m_a = 10^{-23}$ eV. We conclude that the self-gravity of the DM wake cannot be ignored. Its inclusion raises the wake's density by $\sim 10\%$, and holds the wake together over larger distances ($\sim$ 50 kpc) than if self-gravity is ignored. The DM wake's mass is comparable to the LMC's infall mass, meaning the DM wake is a significant perturber to the dynamics of MW halo tracers. An FDM wake is more granular in structure and is $\sim 20\%$ dynamically colder than a CDM wake, but with comparable density. The granularity of an FDM wake increases the stars' kinematic response at the percent level compared to CDM, providing a possible avenue of distinguishing a CDM vs. FDM wake. This underscores the need for kinematic measurements of stars in the stellar halo at distances of 70-100 kpc. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.00053v2-abstract-full').style.display = 'none'; document.getElementById('2307.00053v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">38 pages, 31 figures. Updated to published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 954 163 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.12302">arXiv:2306.12302</a> <span> [<a href="https://arxiv.org/pdf/2306.12302">pdf</a>, <a href="https://arxiv.org/format/2306.12302">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> RomAndromeda: The Roman Survey of the Andromeda Halo </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dey%2C+A">Arjun Dey</a>, <a href="/search/astro-ph?searchtype=author&query=Najita%2C+J">Joan Najita</a>, <a href="/search/astro-ph?searchtype=author&query=Filion%2C+C">Carrie Filion</a>, <a href="/search/astro-ph?searchtype=author&query=Han%2C+J+J">Jiwon Jesse Han</a>, <a href="/search/astro-ph?searchtype=author&query=Pearson%2C+S">Sarah Pearson</a>, <a href="/search/astro-ph?searchtype=author&query=Wyse%2C+R">Rosemary Wyse</a>, <a href="/search/astro-ph?searchtype=author&query=Thob%2C+A+C+R">Adrien C. R. Thob</a>, <a href="/search/astro-ph?searchtype=author&query=Anguiano%2C+B">Borja Anguiano</a>, <a href="/search/astro-ph?searchtype=author&query=Apfel%2C+M">Miranda Apfel</a>, <a href="/search/astro-ph?searchtype=author&query=Arnaboldi%2C+M">Magda Arnaboldi</a>, <a href="/search/astro-ph?searchtype=author&query=Bell%2C+E+F">Eric F. Bell</a>, <a href="/search/astro-ph?searchtype=author&query=Silva%2C+L+B+e">Leandro Beraldo e Silva</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharya%2C+A">Aparajito Bhattacharya</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharya%2C+S">Souradeep Bhattacharya</a>, <a href="/search/astro-ph?searchtype=author&query=Chandra%2C+V">Vedant Chandra</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Collins%2C+M+L+M">Michelle L. M. Collins</a>, <a href="/search/astro-ph?searchtype=author&query=Cunningham%2C+E+C">Emily C. Cunningham</a>, <a href="/search/astro-ph?searchtype=author&query=Dalcanton%2C+J+J">Julianne J. Dalcanton</a>, <a href="/search/astro-ph?searchtype=author&query=Escala%2C+I">Ivanna Escala</a>, <a href="/search/astro-ph?searchtype=author&query=Foote%2C+H+R">Hayden R. Foote</a>, <a href="/search/astro-ph?searchtype=author&query=Ferguson%2C+A+M+N">Annette M. N. Ferguson</a>, <a href="/search/astro-ph?searchtype=author&query=Gibson%2C+B+J">Benjamin J. Gibson</a>, <a href="/search/astro-ph?searchtype=author&query=Gnedin%2C+O+Y">Oleg Y. Gnedin</a> , et al. (28 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.12302v1-abstract-short" style="display: inline;"> As our nearest large neighbor, the Andromeda Galaxy provides a unique laboratory for investigating galaxy formation and the distribution and substructure properties of dark matter in a Milky Way-like galaxy. Here, we propose an initial 2-epoch ($螖t\approx 5$yr), 2-band Roman survey of the entire halo of Andromeda, covering 500 square degrees, which will detect nearly every red giant star in the ha… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.12302v1-abstract-full').style.display = 'inline'; document.getElementById('2306.12302v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.12302v1-abstract-full" style="display: none;"> As our nearest large neighbor, the Andromeda Galaxy provides a unique laboratory for investigating galaxy formation and the distribution and substructure properties of dark matter in a Milky Way-like galaxy. Here, we propose an initial 2-epoch ($螖t\approx 5$yr), 2-band Roman survey of the entire halo of Andromeda, covering 500 square degrees, which will detect nearly every red giant star in the halo (10$蟽$ detection in F146, F062 of 26.5, 26.1AB mag respectively) and yield proper motions to $\sim$25 microarcsec/year (i.e., $\sim$90 km/s) for all stars brighter than F146 $\approx 23.6$ AB mag (i.e., reaching the red clump stars in the Andromeda halo). This survey will yield (through averaging) high-fidelity proper motions for all satellites and compact substructures in the Andromeda halo and will enable statistical searches for clusters in chemo-dynamical space. Adding a third epoch during the extended mission will improve these proper motions by $\sim t^{-1.5}$, to $\approx 11$ km/s, but this requires obtaining the first epoch in Year 1 of Roman operations. In combination with ongoing and imminent spectroscopic campaigns with ground-based telescopes, this Roman survey has the potential to yield full 3-d space motions of $>$100,000 stars in the Andromeda halo, including (by combining individual measurements) robust space motions of its entire globular cluster and most of its dwarf galaxy satellite populations. It will also identify high-velocity stars in Andromeda, providing unique information on the processes that create this population. These data offer a unique opportunity to study the immigration history, halo formation, and underlying dark matter scaffolding of a galaxy other than our own. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.12302v1-abstract-full').style.display = 'none'; document.getElementById('2306.12302v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted in response to the call for Roman Space Telescope Core Community Survey white papers</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.11784">arXiv:2306.11784</a> <span> [<a href="https://arxiv.org/pdf/2306.11784">pdf</a>, <a href="https://arxiv.org/format/2306.11784">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> </div> <p class="title is-5 mathjax"> NANCY: Next-generation All-sky Near-infrared Community surveY </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Han%2C+J+J">Jiwon Jesse Han</a>, <a href="/search/astro-ph?searchtype=author&query=Dey%2C+A">Arjun Dey</a>, <a href="/search/astro-ph?searchtype=author&query=Price-Whelan%2C+A+M">Adrian M. Price-Whelan</a>, <a href="/search/astro-ph?searchtype=author&query=Najita%2C+J">Joan Najita</a>, <a href="/search/astro-ph?searchtype=author&query=Schlafly%2C+E+F">Edward F. Schlafly</a>, <a href="/search/astro-ph?searchtype=author&query=Saydjari%2C+A">Andrew Saydjari</a>, <a href="/search/astro-ph?searchtype=author&query=Wechsler%2C+R+H">Risa H. Wechsler</a>, <a href="/search/astro-ph?searchtype=author&query=Bonaca%2C+A">Ana Bonaca</a>, <a href="/search/astro-ph?searchtype=author&query=Schlegel%2C+D+J">David J Schlegel</a>, <a href="/search/astro-ph?searchtype=author&query=Conroy%2C+C">Charlie Conroy</a>, <a href="/search/astro-ph?searchtype=author&query=Raichoor%2C+A">Anand Raichoor</a>, <a href="/search/astro-ph?searchtype=author&query=Drlica-Wagner%2C+A">Alex Drlica-Wagner</a>, <a href="/search/astro-ph?searchtype=author&query=Kollmeier%2C+J+A">Juna A. Kollmeier</a>, <a href="/search/astro-ph?searchtype=author&query=Koposov%2C+S+E">Sergey E. Koposov</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Rix%2C+H">Hans-Walter Rix</a>, <a href="/search/astro-ph?searchtype=author&query=Goodman%2C+A">Alyssa Goodman</a>, <a href="/search/astro-ph?searchtype=author&query=Finkbeiner%2C+D">Douglas Finkbeiner</a>, <a href="/search/astro-ph?searchtype=author&query=Anand%2C+A">Abhijeet Anand</a>, <a href="/search/astro-ph?searchtype=author&query=Ashby%2C+M">Matthew Ashby</a>, <a href="/search/astro-ph?searchtype=author&query=Bahr-Kalus%2C+B">Benedict Bahr-Kalus</a>, <a href="/search/astro-ph?searchtype=author&query=Beaton%2C+R">Rachel Beaton</a>, <a href="/search/astro-ph?searchtype=author&query=Behera%2C+J">Jayashree Behera</a>, <a href="/search/astro-ph?searchtype=author&query=Bell%2C+E+F">Eric F. Bell</a>, <a href="/search/astro-ph?searchtype=author&query=Bellm%2C+E+C">Eric C Bellm</a> , et al. (184 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.11784v1-abstract-short" style="display: inline;"> The Nancy Grace Roman Space Telescope is capable of delivering an unprecedented all-sky, high-spatial resolution, multi-epoch infrared map to the astronomical community. This opportunity arises in the midst of numerous ground- and space-based surveys that will provide extensive spectroscopy and imaging together covering the entire sky (such as Rubin/LSST, Euclid, UNIONS, SPHEREx, DESI, SDSS-V, GAL… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.11784v1-abstract-full').style.display = 'inline'; document.getElementById('2306.11784v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.11784v1-abstract-full" style="display: none;"> The Nancy Grace Roman Space Telescope is capable of delivering an unprecedented all-sky, high-spatial resolution, multi-epoch infrared map to the astronomical community. This opportunity arises in the midst of numerous ground- and space-based surveys that will provide extensive spectroscopy and imaging together covering the entire sky (such as Rubin/LSST, Euclid, UNIONS, SPHEREx, DESI, SDSS-V, GALAH, 4MOST, WEAVE, MOONS, PFS, UVEX, NEO Surveyor, etc.). Roman can uniquely provide uniform high-spatial-resolution (~0.1 arcsec) imaging over the entire sky, vastly expanding the science reach and precision of all of these near-term and future surveys. This imaging will not only enhance other surveys, but also facilitate completely new science. By imaging the full sky over two epochs, Roman can measure the proper motions for stars across the entire Milky Way, probing 100 times fainter than Gaia out to the very edge of the Galaxy. Here, we propose NANCY: a completely public, all-sky survey that will create a high-value legacy dataset benefiting innumerable ongoing and forthcoming studies of the universe. NANCY is a pure expression of Roman's potential: it images the entire sky, at high spatial resolution, in a broad infrared bandpass that collects as many photons as possible. The majority of all ongoing astronomical surveys would benefit from incorporating observations of NANCY into their analyses, whether these surveys focus on nearby stars, the Milky Way, near-field cosmology, or the broader universe. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.11784v1-abstract-full').style.display = 'none'; document.getElementById('2306.11784v1-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 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to the call for white papers for the Roman Core Community Survey (June 16th, 2023), and to the Bulletin of the AAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.13360">arXiv:2305.13360</a> <span> [<a href="https://arxiv.org/pdf/2305.13360">pdf</a>, <a href="https://arxiv.org/format/2305.13360">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> The Hubble Space Telescope Survey of M31 Satellite Galaxies II. The Star Formation Histories of Ultra-Faint Dwarf Galaxies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Savino%2C+A">A. Savino</a>, <a href="/search/astro-ph?searchtype=author&query=Weisz%2C+D+R">D. R. Weisz</a>, <a href="/search/astro-ph?searchtype=author&query=Skillman%2C+E+D">E. D. Skillman</a>, <a href="/search/astro-ph?searchtype=author&query=Dolphin%2C+A">A. Dolphin</a>, <a href="/search/astro-ph?searchtype=author&query=Cole%2C+A+A">A. A. Cole</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">N. Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Wetzel%2C+A">A. Wetzel</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+J">J. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">G. Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Boylan-Kolchin%2C+M">M. Boylan-Kolchin</a>, <a href="/search/astro-ph?searchtype=author&query=Brown%2C+T+M">T. M. Brown</a>, <a href="/search/astro-ph?searchtype=author&query=Bullock%2C+J+S">J. S. Bullock</a>, <a href="/search/astro-ph?searchtype=author&query=Collins%2C+M+L+M">M. L. M. Collins</a>, <a href="/search/astro-ph?searchtype=author&query=Cooper%2C+M+C">M. C. Cooper</a>, <a href="/search/astro-ph?searchtype=author&query=Deason%2C+A+J">A. J. Deason</a>, <a href="/search/astro-ph?searchtype=author&query=Dotter%2C+A+L">A. L. Dotter</a>, <a href="/search/astro-ph?searchtype=author&query=Fardal%2C+M">M. Fardal</a>, <a href="/search/astro-ph?searchtype=author&query=Ferguson%2C+A+M+N">A. M. N. Ferguson</a>, <a href="/search/astro-ph?searchtype=author&query=Fritz%2C+T+K">T. K. Fritz</a>, <a href="/search/astro-ph?searchtype=author&query=Geha%2C+M+C">M. C. Geha</a>, <a href="/search/astro-ph?searchtype=author&query=Gilbert%2C+K+M">K. M. Gilbert</a>, <a href="/search/astro-ph?searchtype=author&query=Guhathakurta%2C+P">P. Guhathakurta</a>, <a href="/search/astro-ph?searchtype=author&query=Ibata%2C+R">R. Ibata</a>, <a href="/search/astro-ph?searchtype=author&query=Irwin%2C+M+J">M. J. Irwin</a>, <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">M. Jeon</a> , et al. (12 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="2305.13360v2-abstract-short" style="display: inline;"> We present the lifetime star formation histories (SFHs) for six ultra-faint dwarf (UFD; $M_V>-7.0$, $ 4.9<\log_{10}({M_*(z=0)}/{M_{\odot}})<5.5$) satellite galaxies of M31 based on deep color-magnitude diagrams constructed from \textit{Hubble Space Telescope} imaging. These are the first SFHs obtained from the oldest main sequence turn-off of UFDs outside the halo of the Milky Way (MW). We find th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.13360v2-abstract-full').style.display = 'inline'; document.getElementById('2305.13360v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.13360v2-abstract-full" style="display: none;"> We present the lifetime star formation histories (SFHs) for six ultra-faint dwarf (UFD; $M_V>-7.0$, $ 4.9<\log_{10}({M_*(z=0)}/{M_{\odot}})<5.5$) satellite galaxies of M31 based on deep color-magnitude diagrams constructed from \textit{Hubble Space Telescope} imaging. These are the first SFHs obtained from the oldest main sequence turn-off of UFDs outside the halo of the Milky Way (MW). We find that five UFDs formed at least 50\% of their stellar mass by $z=5$ (12.6~Gyr ago), similar to known UFDs around the MW, but that 10-40\% of their stellar mass formed at later times. We uncover one remarkable UFD, \A{XIII}, which formed only 10\% of its stellar mass by $z=5$, and 75\% in a rapid burst at $z\sim2-3$, a result that is robust to choices of underlying stellar model and is consistent with its predominantly red horizontal branch. This "young" UFD is the first of its kind and indicates that not all UFDs are necessarily quenched by reionization, which is consistent with predictions from several cosmological simulations of faint dwarf galaxies. SFHs of the combined MW and M31 samples suggest reionization did not homogeneously quench UFDs. We find that the least massive MW UFDs ($M_*(z=5) \lesssim 5\times10^4 M_{\odot}$) are likely quenched by reionization, whereas more massive M31 UFDs ($M_*(z=5) \gtrsim 10^5 M_{\odot}$) may only have their star formation suppressed by reionization and quench at a later time. We discuss these findings in the context of the evolution and quenching of UFDs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.13360v2-abstract-full').style.display = 'none'; document.getElementById('2305.13360v2-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 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">18 pages, 14 figures, 5 appendices, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.04281">arXiv:2302.04281</a> <span> [<a href="https://arxiv.org/pdf/2302.04281">pdf</a>, <a href="https://arxiv.org/format/2302.04281">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1475-7516/2023/10/070">10.1088/1475-7516/2023/10/070 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The impact of the Large Magellanic Cloud on dark matter direct detection signals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smith-Orlik%2C+A">Adam Smith-Orlik</a>, <a href="/search/astro-ph?searchtype=author&query=Ronaghi%2C+N">Nima Ronaghi</a>, <a href="/search/astro-ph?searchtype=author&query=Bozorgnia%2C+N">Nassim Bozorgnia</a>, <a href="/search/astro-ph?searchtype=author&query=Cautun%2C+M">Marius Cautun</a>, <a href="/search/astro-ph?searchtype=author&query=Fattahi%2C+A">Azadeh Fattahi</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Frenk%2C+C+S">Carlos S. Frenk</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicol谩s Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3mez%2C+F+A">Facundo A. G贸mez</a>, <a href="/search/astro-ph?searchtype=author&query=Grand%2C+R+J+J">Robert J. J. Grand</a>, <a href="/search/astro-ph?searchtype=author&query=Marinacci%2C+F">Federico Marinacci</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+A+H+G">Annika H. G. Peter</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2302.04281v2-abstract-short" style="display: inline;"> We study the effect of the Large Magellanic Cloud (LMC) on the dark matter (DM) distribution in the Solar neighborhood, utilizing the Auriga magneto-hydrodynamical simulations of Milky Way (MW) analogues that have an LMC-like system. We extract the local DM velocity distribution at different times during the orbit of the LMC around the MW in the simulations. As found in previous idealized simulati… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.04281v2-abstract-full').style.display = 'inline'; document.getElementById('2302.04281v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.04281v2-abstract-full" style="display: none;"> We study the effect of the Large Magellanic Cloud (LMC) on the dark matter (DM) distribution in the Solar neighborhood, utilizing the Auriga magneto-hydrodynamical simulations of Milky Way (MW) analogues that have an LMC-like system. We extract the local DM velocity distribution at different times during the orbit of the LMC around the MW in the simulations. As found in previous idealized simulations of the MW-LMC system, we find that the DM particles in the Solar neighborhood originating from the LMC analogue dominate the high speed tail of the local DM speed distribution. Furthermore, the native DM particles of the MW in the Solar region are boosted to higher speeds as a result of a response to the LMC's motion. We simulate the signals expected in near future xenon, germanium, and silicon direct detection experiments, considering DM interactions with target nuclei or electrons. We find that the presence of the LMC causes a considerable shift in the expected direct detection exclusion limits towards smaller cross sections and DM masses, with the effect being more prominent for low mass DM. Hence, our study shows, for the first time, that the LMC's influence on the local DM distribution is significant even in fully cosmological MW analogues. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.04281v2-abstract-full').style.display = 'none'; document.getElementById('2302.04281v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">35 pages, 14 figures, 3 tables, JCAP accepted version</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.16577">arXiv:2211.16577</a> <span> [<a href="https://arxiv.org/pdf/2211.16577">pdf</a>, <a href="https://arxiv.org/format/2211.16577">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stad1724">10.1093/mnras/stad1724 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Lopsided Galaxies in a cosmological context: a new galaxy-halo connection </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Varela-Lavin%2C+S">Silvio Varela-Lavin</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3mez%2C+F+A">Facundo A. G贸mez</a>, <a href="/search/astro-ph?searchtype=author&query=Tissera%2C+P+B">Patricia B. Tissera</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicol谩s Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Marinacci%2C+F">Federico Marinacci</a>, <a href="/search/astro-ph?searchtype=author&query=Laporte%2C+C+F+P">Chervin F. P. Laporte</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="2211.16577v2-abstract-short" style="display: inline;"> Disc galaxies commonly show asymmetric features in their morphology, such as warps and lopsidedness. These features can provide key information regarding the recent evolution of a given disc galaxy. In the nearby Universe, up to $\sim30$ percent of late-type galaxies display a global non-axisymmetric lopsided mass distribution. However, the origin of this perturbation is not well understood. In th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.16577v2-abstract-full').style.display = 'inline'; document.getElementById('2211.16577v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.16577v2-abstract-full" style="display: none;"> Disc galaxies commonly show asymmetric features in their morphology, such as warps and lopsidedness. These features can provide key information regarding the recent evolution of a given disc galaxy. In the nearby Universe, up to $\sim30$ percent of late-type galaxies display a global non-axisymmetric lopsided mass distribution. However, the origin of this perturbation is not well understood. In this work, we study the origin of lopsided perturbations in simulated disc galaxies extracted from the TNG50 simulation of the IllustrisTNG project. We statistically explore different excitation mechanisms for this perturbation, such as direct satellite tidal interactions and distortions of the underlying dark matter distributions. We also characterize the main physical conditions that lead to lopsided perturbations. 50 percent of our sample galaxy have lopsided modes $m=1$ greater than $\sim 0.12$. We find a strong correlation between internal galaxy properties, such as central stellar surface density and disc radial extension with the strength of lopsided modes. The majority of lopsided galaxies have lower central surface densities and more extended discs than symmetric galaxies. As a result, such lopsided galaxies are less self-gravitationally cohesive, and their outer disc region is more susceptible to different types of external perturbations. However, we do not find strong evidence that tidal interactions with satellite galaxies are the main driving agent of lopsided modes. Lopsided galaxies tend to live in asymmetric dark matter halos with high spin, indicating strong galaxy-halo connections in late-type lopsided galaxies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.16577v2-abstract-full').style.display = 'none'; document.getElementById('2211.16577v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 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">16 pages, 16 figures, accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.02801">arXiv:2206.02801</a> <span> [<a href="https://arxiv.org/pdf/2206.02801">pdf</a>, <a href="https://arxiv.org/format/2206.02801">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac91cb">10.3847/1538-4357/ac91cb <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Hubble Space Telescope Survey of M31 Satellite Galaxies I. RR Lyrae-based Distances and Refined 3D Geometric Structure </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Savino%2C+A">Alessandro Savino</a>, <a href="/search/astro-ph?searchtype=author&query=Weisz%2C+D+R">Daniel R. Weisz</a>, <a href="/search/astro-ph?searchtype=author&query=Skillman%2C+E+D">Evan D. Skillman</a>, <a href="/search/astro-ph?searchtype=author&query=Dolphin%2C+A">Andrew Dolphin</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Wetzel%2C+A">Andrew Wetzel</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+J">Jay Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Boylan-Kolchin%2C+M">Michael Boylan-Kolchin</a>, <a href="/search/astro-ph?searchtype=author&query=Bullock%2C+J+S">James S. Bullock</a>, <a href="/search/astro-ph?searchtype=author&query=Cole%2C+A+A">Andrew A. Cole</a>, <a href="/search/astro-ph?searchtype=author&query=Collins%2C+M+L+M">Michelle L. M. Collins</a>, <a href="/search/astro-ph?searchtype=author&query=Cooper%2C+M+C">M. C. Cooper</a>, <a href="/search/astro-ph?searchtype=author&query=Deason%2C+A+J">Alis J. Deason</a>, <a href="/search/astro-ph?searchtype=author&query=Dotter%2C+A+L">Aaron L. Dotter</a>, <a href="/search/astro-ph?searchtype=author&query=Fardal%2C+M">Mark Fardal</a>, <a href="/search/astro-ph?searchtype=author&query=Ferguson%2C+A+M+N">Annette M. N. Ferguson</a>, <a href="/search/astro-ph?searchtype=author&query=Fritz%2C+T+K">Tobias K. Fritz</a>, <a href="/search/astro-ph?searchtype=author&query=Geha%2C+M+C">Marla C. Geha</a>, <a href="/search/astro-ph?searchtype=author&query=Gilbert%2C+K+M">Karoline M. Gilbert</a>, <a href="/search/astro-ph?searchtype=author&query=Guhathakurta%2C+P">Puragra Guhathakurta</a>, <a href="/search/astro-ph?searchtype=author&query=Ibata%2C+R">Rodrigo Ibata</a>, <a href="/search/astro-ph?searchtype=author&query=Irwin%2C+M+J">Michael J. Irwin</a>, <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">Myoungwon Jeon</a>, <a href="/search/astro-ph?searchtype=author&query=Kirby%2C+E">Evan Kirby</a> , et al. (11 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="2206.02801v2-abstract-short" style="display: inline;"> We measure homogeneous distances to M31 and 38 associated stellar systems ($-$16.8$\le M_V \le$ $-$6.0), using time-series observations of RR Lyrae stars taken as part of the Hubble Space Telescope Treasury Survey of M31 Satellites. From $>700$ orbits of new/archival ACS imaging, we identify $>4700$ RR Lyrae stars and determine their periods and mean magnitudes to a typical precision of 0.01 days… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.02801v2-abstract-full').style.display = 'inline'; document.getElementById('2206.02801v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.02801v2-abstract-full" style="display: none;"> We measure homogeneous distances to M31 and 38 associated stellar systems ($-$16.8$\le M_V \le$ $-$6.0), using time-series observations of RR Lyrae stars taken as part of the Hubble Space Telescope Treasury Survey of M31 Satellites. From $>700$ orbits of new/archival ACS imaging, we identify $>4700$ RR Lyrae stars and determine their periods and mean magnitudes to a typical precision of 0.01 days and 0.04 mag. Based on Period-Wesenheit-Metallicity relationships consistent with the Gaia eDR3 distance scale, we uniformly measure heliocentric and M31-centric distances to a typical precision of $\sim20$ kpc (3%) and $\sim10$ kpc (8%), respectively. We revise the 3D structure of the M31 galactic ecosystem and: (i) confirm a highly anisotropic spatial distribution such that $\sim80$% of M31's satellites reside on the near side of M31; this feature is not easily explained by observational effects; (ii) affirm the thin (rms $7-23$ kpc) planar "arc" of satellites that comprises roughly half (15) of the galaxies within 300 kpc from M31; (iii) reassess physical proximity of notable associations such as the NGC 147/185 pair and M33/AND XXII; and (iv) illustrate challenges in tip-of-the-red-giant branch distances for galaxies with $M_V > -9.5$, which can be biased by up to 35%. We emphasize the importance of RR Lyrae for accurate distances to faint galaxies that should be discovered by upcoming facilities (e.g., Rubin Observatory). We provide updated luminosities and sizes for our sample. Our distances will serve as the basis for future investigation of the star formation and orbital histories of the entire known M31 satellite system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.02801v2-abstract-full').style.display = 'none'; document.getElementById('2206.02801v2-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 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">32 pages, 15 figures, accepted for publication on 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/2204.07173">arXiv:2204.07173</a> <span> [<a href="https://arxiv.org/pdf/2204.07173">pdf</a>, <a href="https://arxiv.org/format/2204.07173">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aca01f">10.3847/1538-4357/aca01f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Implications of the Milky Way travel velocity for dynamical mass estimates of the Local Group </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chamberlain%2C+K">Katie Chamberlain</a>, <a href="/search/astro-ph?searchtype=author&query=Price-Whelan%2C+A+M">Adrian M. Price-Whelan</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Cunningham%2C+E+C">Emily C. Cunningham</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicol谩s Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Pe%C3%B1arrubia%2C+J">Jorge Pe帽arrubia</a>, <a href="/search/astro-ph?searchtype=author&query=Petersen%2C+M+S">Michael S. Petersen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2204.07173v2-abstract-short" style="display: inline;"> The total mass of the Local Group (LG) is a fundamental quantity that enables interpreting the orbits of its constituent galaxies and placing the LG in a cosmological context. One of the few methods that allows inferring the total mass directly is the "Timing Argument," which models the relative orbit of the Milky Way (MW) and M31 in equilibrium. The MW itself is not in equilibrium, a byproduct of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.07173v2-abstract-full').style.display = 'inline'; document.getElementById('2204.07173v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.07173v2-abstract-full" style="display: none;"> The total mass of the Local Group (LG) is a fundamental quantity that enables interpreting the orbits of its constituent galaxies and placing the LG in a cosmological context. One of the few methods that allows inferring the total mass directly is the "Timing Argument," which models the relative orbit of the Milky Way (MW) and M31 in equilibrium. The MW itself is not in equilibrium, a byproduct of its merger history including the recent pericentric passage of the LMC, and recent work has found that the MW disk is moving with a lower bound "travel velocity" of $\sim 32~{\rm km}~{\rm s}^{-1}$ with respect to the outer stellar halo. Previous Timing Argument measurements attempt to account for this non-equilibrium state, but have been restricted to theoretical predictions for the impact of the LMC specifically. In this paper, we quantify the impact of a travel velocity on recovered LG mass estimates using several different compilations of recent kinematic measurements of M31. We find that incorporating the measured value of the travel velocity lowers the inferred LG mass by 10--12\% compared to a static MW halo. Measurements of the travel velocity with more distant tracers could yield even larger values, which would further decrease the inferred LG mass. Therefore, the newly measured travel velocity directly implies a lower LG mass than from a model with a static MW halo and must be considered in future dynamical studies of the Local Volume. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.07173v2-abstract-full').style.display = 'none'; document.getElementById('2204.07173v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 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">14 pages, 3 figures; Published in ApJ; updated to match published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 942 18 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.01917">arXiv:2204.01917</a> <span> [<a href="https://arxiv.org/pdf/2204.01917">pdf</a>, <a href="https://arxiv.org/format/2204.01917">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac7226">10.3847/1538-4357/ac7226 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Structural parameters and possible association of the Ultra-Faint Dwarfs Pegasus III and Pisces II from deep Hubble Space Telescope photometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Richstein%2C+H">Hannah Richstein</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Simon%2C+J+D">Joshua D. Simon</a>, <a href="/search/astro-ph?searchtype=author&query=Zivick%2C+P">Paul Zivick</a>, <a href="/search/astro-ph?searchtype=author&query=Tollerud%2C+E">Erik Tollerud</a>, <a href="/search/astro-ph?searchtype=author&query=Fritz%2C+T">Tobias Fritz</a>, <a href="/search/astro-ph?searchtype=author&query=Warfield%2C+J+T">Jack T. Warfield</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Wetzel%2C+A">Andrew Wetzel</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Deason%2C+A">Alis Deason</a>, <a href="/search/astro-ph?searchtype=author&query=Geha%2C+M">Marla Geha</a>, <a href="/search/astro-ph?searchtype=author&query=Guhathakurta%2C+P">Puragra Guhathakurta</a>, <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">Myoungwon Jeon</a>, <a href="/search/astro-ph?searchtype=author&query=Kirby%2C+E+N">Evan N. Kirby</a>, <a href="/search/astro-ph?searchtype=author&query=Libralato%2C+M">Mattia Libralato</a>, <a href="/search/astro-ph?searchtype=author&query=Sacchi%2C+E">Elena Sacchi</a>, <a href="/search/astro-ph?searchtype=author&query=Sohn%2C+S+T">Sangmo Tony Sohn</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2204.01917v2-abstract-short" style="display: inline;"> We present deep Hubble Space Telescope (HST) photometry of the ultra-faint dwarf (UFD) galaxies Pegasus III (Peg III) and Pisces II (Psc II), two of the most distant satellites in the halo of the Milky Way (MW). We measure the structure of both galaxies, derive mass-to-light ratios with newly determined absolute magnitudes, and compare our findings to expectations from UFD-mass simulations. For Pe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.01917v2-abstract-full').style.display = 'inline'; document.getElementById('2204.01917v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.01917v2-abstract-full" style="display: none;"> We present deep Hubble Space Telescope (HST) photometry of the ultra-faint dwarf (UFD) galaxies Pegasus III (Peg III) and Pisces II (Psc II), two of the most distant satellites in the halo of the Milky Way (MW). We measure the structure of both galaxies, derive mass-to-light ratios with newly determined absolute magnitudes, and compare our findings to expectations from UFD-mass simulations. For Peg III, we find an elliptical half-light radius of $a_h=1.88^{+0.42}_{-0.33}$ arcminutes ($118^{+31}_{-30}$ pc) and $M_V{=}{-4.17}^{+0.19}_{-0.22}$; for Psc II, we measure $a_h{=}1.31^{+0.10}_{-0.09}$ arcminutes ($69\pm8$ pc) and $M_V{=}{-4.28}^{+0.19}_{-0.16}$. We do not find any morphological features that indicate a significant interaction between the two has occurred, despite their close separation of only $\sim$40 kpc. Using proper motions (PMs) from Gaia early Data Release 3, we investigate the possibility of any past association by integrating orbits for the two UFDs in a MW-only and a combined MW and Large Magellanic Cloud (LMC) potential. We find that including the gravitational influence of the LMC is crucial, even for these outer-halo satellites, and that a possible orbital history exists where Peg III and Psc II experienced a close ($\sim$10-20 kpc) passage about each other just over $\sim$1 Gyr ago, followed by a collective passage around the LMC ($\sim$30-60 kpc) just under $\sim$1 Gyr ago. Considering the large uncertainties on the PMs and the restrictive priors imposed to derive them, improved PM measurements for Peg III and Psc II will be necessary to clarify their relationship. This would add to the rare findings of confirmed pairs of satellites within the Local Group. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.01917v2-abstract-full').style.display = 'none'; document.getElementById('2204.01917v2-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 13 figures; 1 appendix; published in ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, Volume 933, Issue 2, id.217, July 2022 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2203.09523">arXiv:2203.09523</a> <span> [<a href="https://arxiv.org/pdf/2203.09523">pdf</a>, <a href="https://arxiv.org/format/2203.09523">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnrasl/slac030">10.1093/mnrasl/slac030 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The synchronised dance of the Magellanic Clouds' star formation history </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Massana%2C+P">P. Massana</a>, <a href="/search/astro-ph?searchtype=author&query=Ruiz-Lara%2C+T">T. Ruiz-Lara</a>, <a href="/search/astro-ph?searchtype=author&query=No%C3%ABl%2C+N+E+D">N. E. D. No毛l</a>, <a href="/search/astro-ph?searchtype=author&query=Gallart%2C+C">C. Gallart</a>, <a href="/search/astro-ph?searchtype=author&query=Nidever%2C+D+L">D. L. Nidever</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Y. Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Sakowska%2C+J+D">J. D. Sakowska</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">G. Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Olsen%2C+K+A+G">K. A. G. Olsen</a>, <a href="/search/astro-ph?searchtype=author&query=Monelli%2C+M">M. Monelli</a>, <a href="/search/astro-ph?searchtype=author&query=Dorta%2C+A">A. Dorta</a>, <a href="/search/astro-ph?searchtype=author&query=Stringfellow%2C+G+S">G. S. Stringfellow</a>, <a href="/search/astro-ph?searchtype=author&query=Cassisi%2C+S">S. Cassisi</a>, <a href="/search/astro-ph?searchtype=author&query=Bernard%2C+E+J">E. J. Bernard</a>, <a href="/search/astro-ph?searchtype=author&query=Zaritsky%2C+D">D. Zaritsky</a>, <a href="/search/astro-ph?searchtype=author&query=Cioni%2C+M+-+L">M. -R. L. Cioni</a>, <a href="/search/astro-ph?searchtype=author&query=Monachesi%2C+A">A. Monachesi</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">R. P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=de+Boer%2C+T+J+L">T. J. L. de Boer</a>, <a href="/search/astro-ph?searchtype=author&query=Walker%2C+A+R">A. R. Walker</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2203.09523v1-abstract-short" style="display: inline;"> We use the SMASH survey to obtain unprecedented deep photometry reaching down to the oldest main sequence turn-offs in the colour-magnitude diagrams (CMDs) of the Small Magellanic Cloud (SMC) and quantitatively derive its star formation history (SFH) using CMD fitting techniques. We identify five distinctive peaks of star formation in the last 3.5 Gyr, at $\sim $3, $\sim$2, $\sim$1.1, $\sim $0.45… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.09523v1-abstract-full').style.display = 'inline'; document.getElementById('2203.09523v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.09523v1-abstract-full" style="display: none;"> We use the SMASH survey to obtain unprecedented deep photometry reaching down to the oldest main sequence turn-offs in the colour-magnitude diagrams (CMDs) of the Small Magellanic Cloud (SMC) and quantitatively derive its star formation history (SFH) using CMD fitting techniques. We identify five distinctive peaks of star formation in the last 3.5 Gyr, at $\sim $3, $\sim$2, $\sim$1.1, $\sim $0.45 Gyr ago, and one presently. We compare these to the SFH of the Large Magellanic Cloud (LMC) finding unequivocal synchronicity, with both galaxies displaying similar periods of enhanced star formation over the past $\sim$3.5 Gyr. The parallelism between their SFHs indicates that tidal interactions between the MCs have recurrently played an important role in their evolution for at least the last $\sim$3.5 Gyr, tidally truncating the SMC and shaping the LMC's spiral arm. We show, for the first time, an SMC-LMC correlated SFH at recent times in which enhancements of star formation are localised in the northern spiral arm of the LMC, and globally across the SMC. These novel findings should be used to constrain not only the orbital history of the MCs but also how star formation should be treated in simulations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.09523v1-abstract-full').style.display = 'none'; document.getElementById('2203.09523v1-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 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 4 figures. Accepted for publication to MNRAS 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/2202.12789">arXiv:2202.12789</a> <span> [<a href="https://arxiv.org/pdf/2202.12789">pdf</a>, <a href="https://arxiv.org/format/2202.12789">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac5621">10.3847/1538-4357/ac5621 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Kinematical Analysis of Substructure in the Southern Periphery of the Large Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cheng%2C+X">Xinlun Cheng</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Olsen%2C+K">Knut Olsen</a>, <a href="/search/astro-ph?searchtype=author&query=Nidever%2C+D+L">David L. Nidever</a>, <a href="/search/astro-ph?searchtype=author&query=Majewski%2C+S+R">Steven R. Majewski</a>, <a href="/search/astro-ph?searchtype=author&query=Monachesi%2C+A">Antonela Monachesi</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Mu%C3%B1oz%2C+C">C茅sar Mu帽oz</a>, <a href="/search/astro-ph?searchtype=author&query=Anguiano%2C+B">Borja Anguiano</a>, <a href="/search/astro-ph?searchtype=author&query=Almeida%2C+A">Andres Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=Mu%C3%B1oz%2C+R+R">Ricardo R. Mu帽oz</a>, <a href="/search/astro-ph?searchtype=author&query=Lane%2C+R+R">Richard R. Lane</a>, <a href="/search/astro-ph?searchtype=author&query=Nitschelm%2C+C">Christian Nitschelm</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="2202.12789v1-abstract-short" style="display: inline;"> We report the first 3-D kinematical measurements of 88 stars in the direction of several recently discovered substructures in the southern periphery of the Large Magellanic Cloud (LMC) using a combination of Gaia proper motions and radial velocities from the APOGEE-2 survey. More specifically, we explore stars lie in assorted APOGEE-2 pointings in a region of the LMC periphery where various overde… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.12789v1-abstract-full').style.display = 'inline'; document.getElementById('2202.12789v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.12789v1-abstract-full" style="display: none;"> We report the first 3-D kinematical measurements of 88 stars in the direction of several recently discovered substructures in the southern periphery of the Large Magellanic Cloud (LMC) using a combination of Gaia proper motions and radial velocities from the APOGEE-2 survey. More specifically, we explore stars lie in assorted APOGEE-2 pointings in a region of the LMC periphery where various overdensities of stars have previously been identified in maps of stars from Gaia and DECam. By using a model of the LMC disk rotation, we find that a sizeable fraction of the APOGEE-2 stars have extreme space velocities that are distinct from, and not a simple extension of, the LMC disk. Using N-body hydrodynamical simulations of the past dynamical evolution and interaction of the LMC and Small Magellanic Cloud (SMC), we explore whether the extreme velocity stars may be accounted for as tidal debris created in the course of that interaction. We conclude that the combination of LMC and SMC debris produced from their interaction is a promising explanation, although we cannot rule out other possible origins, and that these new data should be used to constrain future simulations of the LMC-SMC interaction. We also conclude that many of the stars in the southern periphery of the LMC lie out of the LMC plane by several kpc. Given that the metallicity of these stars suggest they are likely of Magellanic origin, our results suggest that a wider exploration of the past interaction history of the Magellanic Clouds is needed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.12789v1-abstract-full').style.display = 'none'; document.getElementById('2202.12789v1-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 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.06887">arXiv:2202.06887</a> <span> [<a href="https://arxiv.org/pdf/2202.06887">pdf</a>, <a href="https://arxiv.org/format/2202.06887">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/10.1093/mnras/stac2265">10.1093/mnras/stac2265 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Kinematics of Luminous Blue Variables in the Large Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aghakhanloo%2C+M">Mojgan Aghakhanloo</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+N">Nathan Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Andrews%2C+J">Jennifer Andrews</a>, <a href="/search/astro-ph?searchtype=author&query=Olsen%2C+K">Knut Olsen</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</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="2202.06887v2-abstract-short" style="display: inline;"> We study the kinematics of luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC). Using high-resolution spectra, we measure the systemic radial velocities for a sample of 16 LBVs and LBV candidates. In order to measure the net motion of LBVs compared to their local environments, we subtract the projected line-of-sight velocity at the same location derived from the rotation curve model… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.06887v2-abstract-full').style.display = 'inline'; document.getElementById('2202.06887v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.06887v2-abstract-full" style="display: none;"> We study the kinematics of luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC). Using high-resolution spectra, we measure the systemic radial velocities for a sample of 16 LBVs and LBV candidates. In order to measure the net motion of LBVs compared to their local environments, we subtract the projected line-of-sight velocity at the same location derived from the rotation curve model of the LMC. Using nebular and wind emission lines, we infer a velocity dispersion for LBVs of $40.0^{+9.9}_{-6.6}$ km s$^{-1}$. To put LBVs in context with other evolved massive stars, we compare this to red supergiants (RSGs) in the LMC, which have a significantly smaller velocity dispersion of $16.5^{+0.4}_{-0.6}$ km s$^{-1}$. Moreover, 33% of LBVs have radial velocities of more than 25 km s$^{-1}$, while only 9% of RSG have such high velocities. This suggests that LBVs include more runaways than the population of stars that evolves to become RSGs, indicating that LBVs are preferentially kicked by a companion's supernova explosion as compared to other evolved massive stars. Our investigation reveals other interesting clues about LBVs in the LMC as well. We find that radial velocities and widths of emission lines for each target remain constant over several epochs, whereas measured absorption lines exhibit highly variable radial velocities for R110, R81, S Dor, Sk-69$^\circ$142a, and Sk-69$^\circ$279. These five LBVs probably have a binary companion. Additionally, we find that Sk-69$^\circ$142a experienced its second outburst in 2019 September, shifting its status from candidate to confirmed LBV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.06887v2-abstract-full').style.display = 'none'; document.getElementById('2202.06887v2-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 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 27 figures, 6 tables, MNRAS accepted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.04648">arXiv:2201.04648</a> <span> [<a href="https://arxiv.org/pdf/2201.04648">pdf</a>, <a href="https://arxiv.org/format/2201.04648">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac4e90">10.3847/1538-4357/ac4e90 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The recent LMC-SMC collision: Timing and impact parameter constraints from comparison of Gaia LMC disk kinematics and N-body simulations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Olsen%2C+K+A+G">Knut A. G. Olsen</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Zivick%2C+P">Paul Zivick</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Nidever%2C+D+L">David L. Nidever</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2201.04648v1-abstract-short" style="display: inline;"> We present analysis of the proper-motion (PM) field of the red clump stars in the Large Magellanic Cloud (LMC) disk using the Gaia Early Data Release 3 catalog. Using a kinematic model based on old stars with 3D velocity measurements, we construct the residual PM field by subtracting the center-of-mass motion and internal rotation motion components. The residual PM field reveals asymmetric pattern… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.04648v1-abstract-full').style.display = 'inline'; document.getElementById('2201.04648v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.04648v1-abstract-full" style="display: none;"> We present analysis of the proper-motion (PM) field of the red clump stars in the Large Magellanic Cloud (LMC) disk using the Gaia Early Data Release 3 catalog. Using a kinematic model based on old stars with 3D velocity measurements, we construct the residual PM field by subtracting the center-of-mass motion and internal rotation motion components. The residual PM field reveals asymmetric patterns, including larger residual PMs in the southern disk. Comparisons between the observed residual PM field with those of five numerical simulations of an LMC analog that is subject to the tidal fields of the Milky Way and the Small Magellanic Cloud (SMC) show that the present-day LMC is not in dynamical equilibrium. We find that both the observed level of disk heating (PM residual root-mean-square of 0.057$\pm$0.002 mas yr$^{-1}$) and kinematic asymmetry are not reproduced by Milky Way tides or if the SMC impact parameter is larger than the size of the LMC disk. This measured level of disk heating provides a novel and important method to validate numerical simulations of the LMC-SMC interaction history. Our results alone put constraints on an impact parameter $\lesssim$10 kpc and impact timing $<$250 Myr. When adopting the impact timing constraint of $\sim$140--160 Myr ago from previous studies, our results suggest that the most recent SMC encounter must have occurred with an impact parameter of $\sim$5 kpc. We also find consistent radial trends in the kinematically- and geometrically-derived disk inclination and line-of-node position angles, indicating a common origin. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.04648v1-abstract-full').style.display = 'none'; document.getElementById('2201.04648v1-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 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 10 figures, resubmitted to AAS 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/2111.04795">arXiv:2111.04795</a> <span> [<a href="https://arxiv.org/pdf/2111.04795">pdf</a>, <a href="https://arxiv.org/format/2111.04795">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-3881/ac3750">10.3847/1538-3881/ac3750 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigating the Baryon Cycle in Interacting Dwarfs with the Very Large Array and Pan-STARRS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Luber%2C+N">Nicholas Luber</a>, <a href="/search/astro-ph?searchtype=author&query=Pearson%2C+S">Sarah Pearson</a>, <a href="/search/astro-ph?searchtype=author&query=Putman%2C+M">Mary Putman</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Stierwalt%2C+S">Sabrina Stierwalt</a>, <a href="/search/astro-ph?searchtype=author&query=Meyers%2C+J+P">Joel P. Meyers</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2111.04795v1-abstract-short" style="display: inline;"> We present resolved HI synthesis maps from the Very Large Array (VLA) of three interacting dwarf systems: the NGC 3664 dwarf pair, the NGC 3264 dwarf pair, and the UGC 4638 dwarf triplet. All three dwarf systems are captured at various stages of interaction and span a range of environments. We detect clear hallmarks of tidal interactions through the presence of HI bridges, and diffuse HI extension… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.04795v1-abstract-full').style.display = 'inline'; document.getElementById('2111.04795v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.04795v1-abstract-full" style="display: none;"> We present resolved HI synthesis maps from the Very Large Array (VLA) of three interacting dwarf systems: the NGC 3664 dwarf pair, the NGC 3264 dwarf pair, and the UGC 4638 dwarf triplet. All three dwarf systems are captured at various stages of interaction and span a range of environments. We detect clear hallmarks of tidal interactions through the presence of HI bridges, and diffuse HI extensions that surround the dwarfs. We overlay the HI data on Pan-STARRS r-band images and find further evidence of tidal interactions through coincident distorted HI and tidal stellar features in NGC 3264 and UGC 4638, and an unwound spiral arm pointing towards its smaller companion in NGC 3264. In UGC 4638, both the gas and diffuse stars are extended to similar radii east of the primary, which could indicate that the smaller dwarf in the system has already completed one pass through the primary. We additionally find that our three systems, and those from the Local Volume TiNy Titans survey, are not HI deficient and thus the interaction has not resulted in a loss of gas from the systems. A comparison with non-interacting dwarf galaxies shows that the interactions have a significant impact on the kinematics of the systems. Our new resolved HI kinematics, combined with detailed stellar and HI morphologies, provide crucial constraints for future dynamical modelling of hierarchical mergers and the baryon cycle at the low-mass scale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.04795v1-abstract-full').style.display = 'none'; document.getElementById('2111.04795v1-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, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 6 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/2108.07321">arXiv:2108.07321</a> <span> [<a href="https://arxiv.org/pdf/2108.07321">pdf</a>, <a href="https://arxiv.org/format/2108.07321">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac2c05">10.3847/1538-4357/ac2c05 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Clustering of Orbital Poles Induced by the LMC: Hints for the Origin of Planes of Satellites </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicolas Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Price-Whelan%2C+A+M">Adrian M. Price-Whelan</a>, <a href="/search/astro-ph?searchtype=author&query=Gomez%2C+F+A">Facundo A. Gomez</a>, <a href="/search/astro-ph?searchtype=author&query=Laporte%2C+C+F+P">Chervin F. P Laporte</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+K+V">Kathryn V. Johnston</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2108.07321v1-abstract-short" style="display: inline;"> A significant fraction of Milky Way (MW) satellites exhibit phase-space properties consistent with a coherent orbital plane. Using tailored N--body simulations of a spherical MW halo that recently captured a massive (1.8$\times 10^{11}$M$\odot$) LMC-like satellite, we identify the physical mechanisms that may enhance the clustering of orbital poles of objects orbiting the MW. The LMC deviates the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.07321v1-abstract-full').style.display = 'inline'; document.getElementById('2108.07321v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.07321v1-abstract-full" style="display: none;"> A significant fraction of Milky Way (MW) satellites exhibit phase-space properties consistent with a coherent orbital plane. Using tailored N--body simulations of a spherical MW halo that recently captured a massive (1.8$\times 10^{11}$M$\odot$) LMC-like satellite, we identify the physical mechanisms that may enhance the clustering of orbital poles of objects orbiting the MW. The LMC deviates the orbital poles of MW dark matter (DM) particles from the present-day random distribution. Instead, the orbital poles of particles beyond $R\approx 50$kpc cluster near the present-day orbital pole of the LMC along a sinusoidal pattern across the sky. The density of orbital poles is enhanced near the LMC by a factor $未蟻_{max}$=30\%(50\%) with respect to underdense regions, and $未蟻_{iso}$=15\%(30\%) relative to the isolated MW simulation (no LMC) between 50-150 kpc (150-300 kpc). The clustering appears after the LMC's pericenter ($\approx$ 50 Myr ago, 49 kpc) and lasts for at least 1 Gyr. Clustering occurs because of three effects: 1) the LMC shifts the velocity and position of the central density of the MW's halo and disk; 2) the DM dynamical friction wake and collective response induced by the LMC changes the kinematics of particles; 3) observations of particles selected within spatial planes suffer from a bias, such that measuring orbital poles in a great circle in the sky enhances the probability of their orbital poles being clustered. This scenario should be ubiquitous in hosts that recently captured a massive satellite (at least $\approx$ 1:10 mass ratio), causing the clustering of orbital poles of halo tracers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.07321v1-abstract-full').style.display = 'none'; document.getElementById('2108.07321v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to ApJ. 23 pages and 16 figures. Comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.04271">arXiv:2108.04271</a> <span> [<a href="https://arxiv.org/pdf/2108.04271">pdf</a>, <a href="https://arxiv.org/format/2108.04271">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/ac2aa3">10.3847/2041-8213/ac2aa3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Star Formation Histories of Ultra-Faint Dwarf Galaxies: environmental differences between Magellanic and non-Magellanic satellites? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sacchi%2C+E">Elena Sacchi</a>, <a href="/search/astro-ph?searchtype=author&query=Richstein%2C+H">Hannah Richstein</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R">Roeland van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Libralato%2C+M">Mattia Libralato</a>, <a href="/search/astro-ph?searchtype=author&query=Zivick%2C+P">Paul Zivick</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Brown%2C+T+M">Thomas M. Brown</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Deason%2C+A">Alis Deason</a>, <a href="/search/astro-ph?searchtype=author&query=Fritz%2C+T">Tobias Fritz</a>, <a href="/search/astro-ph?searchtype=author&query=Geha%2C+M">Marla Geha</a>, <a href="/search/astro-ph?searchtype=author&query=Guhathakurta%2C+P">Puragra Guhathakurta</a>, <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">Myoungwon Jeon</a>, <a href="/search/astro-ph?searchtype=author&query=Kirby%2C+E">Evan Kirby</a>, <a href="/search/astro-ph?searchtype=author&query=Majewski%2C+S+R">Steven R. Majewski</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Simon%2C+J+D">Joshua D. Simon</a>, <a href="/search/astro-ph?searchtype=author&query=Sohn%2C+S+T">Sangmo Tony Sohn</a>, <a href="/search/astro-ph?searchtype=author&query=Tollerud%2C+E">Erik Tollerud</a>, <a href="/search/astro-ph?searchtype=author&query=Wetzel%2C+A">Andrew Wetzel</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2108.04271v2-abstract-short" style="display: inline;"> We present the color-magnitude diagrams and star formation histories (SFHs) of seven ultra-faint dwarf galaxies: Horologium 1, Hydra 2, Phoenix 2, Reticulum 2, Sagittarius 2, Triangulum 2, and Tucana 2, derived from high-precision Hubble Space Telescope photometry. We find that the SFH of each galaxy is consistent with them having created at least 80% of the stellar mass by $z\sim6$. For all galax… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.04271v2-abstract-full').style.display = 'inline'; document.getElementById('2108.04271v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.04271v2-abstract-full" style="display: none;"> We present the color-magnitude diagrams and star formation histories (SFHs) of seven ultra-faint dwarf galaxies: Horologium 1, Hydra 2, Phoenix 2, Reticulum 2, Sagittarius 2, Triangulum 2, and Tucana 2, derived from high-precision Hubble Space Telescope photometry. We find that the SFH of each galaxy is consistent with them having created at least 80% of the stellar mass by $z\sim6$. For all galaxies, we find quenching times older than 11.5 Gyr ago, compatible with the scenario in which reionization suppresses the star formation of small dark matter halos. However, our analysis also reveals some differences in the SFHs of candidate Magellanic Cloud satellites, i.e., galaxies that are likely satellites of the Large Magellanic Cloud and that entered the Milky Way potential only recently. Indeed, Magellanic satellites show quenching times about 600 Myr more recent with respect to those of other Milky Way satellites, on average, even though the respective timings are still compatible within the errors. This finding is consistent with theoretical models that suggest that satellites' SFHs may depend on their host environment at early times, although we caution that within the error bars all galaxies in our sample are consistent with being quenched at a single epoch. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.04271v2-abstract-full').style.display = 'none'; document.getElementById('2108.04271v2-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 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 3 figures, 2 tables. Accepted for publication in ApJL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.13383">arXiv:2106.13383</a> <span> [<a href="https://arxiv.org/pdf/2106.13383">pdf</a>, <a href="https://arxiv.org/format/2106.13383">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stab1771">10.1093/mnras/stab1771 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Highly r-process enhanced stars in ultra-faint dwarf galaxies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">Myoungwon Jeon</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Bromm%2C+V">Volker Bromm</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2106.13383v1-abstract-short" style="display: inline;"> Highly r-process enhanced metal-poor stars (MP r-II, $\rm [Eu/Fe]>1$ and $\rm [Fe/H]\lesssim-1.5$) have been observed in ultra-faint dwarf (UFD) galaxy, specifically in Reticulum~II (Ret~II). The fact that only a few UFDs contain such stars implies that the r-process site may reflect very rare, but individually prolific events, such as neutron star mergers (NSMs). Considering the relatively short… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.13383v1-abstract-full').style.display = 'inline'; document.getElementById('2106.13383v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.13383v1-abstract-full" style="display: none;"> Highly r-process enhanced metal-poor stars (MP r-II, $\rm [Eu/Fe]>1$ and $\rm [Fe/H]\lesssim-1.5$) have been observed in ultra-faint dwarf (UFD) galaxy, specifically in Reticulum~II (Ret~II). The fact that only a few UFDs contain such stars implies that the r-process site may reflect very rare, but individually prolific events, such as neutron star mergers (NSMs). Considering the relatively short star formation history (SFH) of UFDs, it is puzzling how they could experience such a rare phenomenon. In this work, we show the results of cosmological hydrodynamic zoom-in simulations of isolated UFDs ($M_{vir}\approx10^7-10^8$ solar mass and $M_{\ast}\approx10^3-10^4$ solar mass at $z=0$) to explain the formation of MP r-II stars in UFDs. We employ a simple toy model for NSM events, adopting parameters consistent with observations, such as the NSM rate (1 per $M_{\ast}\approx10^5$ solar mass) and europium (Eu) mass ($M_{Eu}\approx10^{-5}$ solar mass). We identify only one simulated galaxy ($ M_{vir}\approx4.6\times10^7$, $M_{\ast}\approx 3.4\times 10^3$ solar mass at $z=0$) with abundances similar to Ret~II in a simulation volume that hosts $\sim30$ UFD analogs, indicating that such abundances are possible but rare. By exploring a range of key parameters, we demonstrate that the most important factor in determining the formation of MP r-II stars in UFDs is how quickly subsequent stars can be formed out of r-process enriched gas. We find that it takes between 10 to 100~Myr to form the first and second burst of MP r-II stars. Over this period, Eu-polluted gas maintains the required high abundance ratios of $\rm [Eu/Fe]>1$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.13383v1-abstract-full').style.display = 'none'; document.getElementById('2106.13383v1-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 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 8 figures, Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.09515">arXiv:2104.09515</a> <span> [<a href="https://arxiv.org/pdf/2104.09515">pdf</a>, <a href="https://arxiv.org/format/2104.09515">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/10.1038/s41586-021-03385-7">10.1038/s41586-021-03385-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Conroy%2C+C">Charlie Conroy</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+R+P">Rohan P. Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicolas Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Zaritsky%2C+D">Dennis Zaritsky</a>, <a href="/search/astro-ph?searchtype=author&query=Bonaca%2C+A">Ana Bonaca</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+B+D">Benjamin D. Johnson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2104.09515v1-abstract-short" style="display: inline;"> Gravitational interactions between the Large Magellanic Cloud (LMC) and the stellar and dark matter halo of the Milky Way are expected to give rise to disequilibrium phenomena in the outer Milky Way. A local wake is predicted to trail the orbit of the LMC, while a large-scale over-density is predicted to exist across a large area of the northern Galactic hemisphere. Here we present the detection o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.09515v1-abstract-full').style.display = 'inline'; document.getElementById('2104.09515v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.09515v1-abstract-full" style="display: none;"> Gravitational interactions between the Large Magellanic Cloud (LMC) and the stellar and dark matter halo of the Milky Way are expected to give rise to disequilibrium phenomena in the outer Milky Way. A local wake is predicted to trail the orbit of the LMC, while a large-scale over-density is predicted to exist across a large area of the northern Galactic hemisphere. Here we present the detection of both the local wake and Northern over-density (hereafter the "collective response") in an all-sky star map of the Galaxy based on 1301 stars at 60<R_gal<100 kpc. The location of the wake is in good agreement with an N-body simulation that includes the dynamical effect of the LMC on the Milky Way halo. The density contrast of the wake and collective response are both stronger in the data than in the simulation. The detection of a strong local wake is independent evidence that the Magellanic Clouds are on their first orbit around the Milky Way. The wake traces the path of the LMC, which will provide insight into the orbit of the LMC, which in turn is a sensitive probe of the mass of the LMC and the Milky Way. These data demonstrate that the outer halo is not in dynamical equilibrium, as is often assumed. The morphology and strength of the wake could be used to test the nature of dark matter and gravity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.09515v1-abstract-full').style.display = 'none'; document.getElementById('2104.09515v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To appear in the 22 April 2021 issue of Nature</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.10012">arXiv:2012.10012</a> <span> [<a href="https://arxiv.org/pdf/2012.10012">pdf</a>, <a href="https://arxiv.org/format/2012.10012">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/staa4017">10.1093/mnras/staa4017 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The role of faint population III supernovae in forming CEMP stars in ultra-faint dwarf galaxies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">Myoungwon Jeon</a>, <a href="/search/astro-ph?searchtype=author&query=Bromm%2C+V">Volker Bromm</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Yoon%2C+J">Jinmi Yoon</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</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="2012.10012v1-abstract-short" style="display: inline;"> CEMP-no stars, a subset of carbon enhanced metal poor (CEMP) stars ($\rm [C/Fe]\geq0.7$ and $\rm [Fe/H]\lesssim-1$) have been discovered in ultra-faint dwarf (UFD) galaxies, with $M_{\rm vir} \sim 10^8$ Msun and $M_{\ast}\sim10^3-10^4$ Msun at $z=0$, as well as in the halo of the Milky Way (MW). These CEMP-no stars are local fossils that may reflect the properties of the first (Pop~III) and second… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.10012v1-abstract-full').style.display = 'inline'; document.getElementById('2012.10012v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.10012v1-abstract-full" style="display: none;"> CEMP-no stars, a subset of carbon enhanced metal poor (CEMP) stars ($\rm [C/Fe]\geq0.7$ and $\rm [Fe/H]\lesssim-1$) have been discovered in ultra-faint dwarf (UFD) galaxies, with $M_{\rm vir} \sim 10^8$ Msun and $M_{\ast}\sim10^3-10^4$ Msun at $z=0$, as well as in the halo of the Milky Way (MW). These CEMP-no stars are local fossils that may reflect the properties of the first (Pop~III) and second (Pop~II) generation of stars. However, cosmological simulations have struggled to reproduce the observed level of carbon enhancement of the known CEMP-no stars. Here we present new cosmological hydrodynamic zoom-in simulations of isolated UFDs that achieve a gas mass resolution of $m_{\rm gas}\sim60$ Msun. We include enrichment from Pop~III faint supernovae (SNe), with $ E_{\rm SN}=0.6\times10^{51}$ erg, to understand the origin of CEMP-no stars. We confirm that Pop~III and Pop~II stars are mainly responsible for the formation of CEMP and C-normal stars respectively. New to this study, we find that a majority of CEMP-no stars in the observed UFDs and the MW halo can be explained by Pop~III SNe with normal explosion energy ($ E_{\rm SN}=1.2\times10^{51}$~erg) and Pop~II enrichment, but faint SNe might also be needed to produce CEMP-no stars with $\rm [C/Fe]\gtrsim2$, corresponding to the absolute carbon abundance of $\rm A(C)\gtrsim6.0$. Furthermore, we find that while we create CEMP-no stars with high carbon ratio $\rm [C/Fe]\approx3-4$, by adopting faint SNe, it is still challenging to reproduce CEMP-no stars with extreme level of carbon abundance of $\rm A(C)\approx 7.0-7.5$, observed both in the MW halo and UFDs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.10012v1-abstract-full').style.display = 'none'; document.getElementById('2012.10012v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 December, 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">14 pages, 8 figures, submitted to MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.13943">arXiv:2011.13943</a> <span> [<a href="https://arxiv.org/pdf/2011.13943">pdf</a>, <a href="https://arxiv.org/format/2011.13943">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-3881/abceb7">10.3847/1538-3881/abceb7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Second Data Release of the Survey of the MAgellanic Stellar History (SMASH) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nidever%2C+D+L">David L. Nidever</a>, <a href="/search/astro-ph?searchtype=author&query=Olsen%2C+K">Knut Olsen</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Ruiz-Lara%2C+T">Tomas Ruiz-Lara</a>, <a href="/search/astro-ph?searchtype=author&query=Miller%2C+A+E">Amy E. Miller</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+L+C">L. Clifton Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Bell%2C+C+P+M">Cameron P. M. Bell</a>, <a href="/search/astro-ph?searchtype=author&query=Blum%2C+R+D">Robert D. Blum</a>, <a href="/search/astro-ph?searchtype=author&query=Cioni%2C+M+L">Maria-Rosa L. Cioni</a>, <a href="/search/astro-ph?searchtype=author&query=Gallart%2C+C">Carme Gallart</a>, <a href="/search/astro-ph?searchtype=author&query=Majewski%2C+S+R">Steven R. Majewski</a>, <a href="/search/astro-ph?searchtype=author&query=Martin%2C+N+F">Nicolas F. Martin</a>, <a href="/search/astro-ph?searchtype=author&query=Massana%2C+P">Pol Massana</a>, <a href="/search/astro-ph?searchtype=author&query=Monachesi%2C+A">Antonela Monachesi</a>, <a href="/search/astro-ph?searchtype=author&query=Noel%2C+N+E+D">Noelia E. D. Noel</a>, <a href="/search/astro-ph?searchtype=author&query=Sakowska%2C+J+D">Joanna D. Sakowska</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Walker%2C+A+R">Alistair R. Walker</a>, <a href="/search/astro-ph?searchtype=author&query=Zaritsky%2C+D">Dennis Zaritsky</a>, <a href="/search/astro-ph?searchtype=author&query=Bell%2C+E+F">Eric F. Bell</a>, <a href="/search/astro-ph?searchtype=author&query=Conn%2C+B+C">Blair C. Conn</a>, <a href="/search/astro-ph?searchtype=author&query=de+Boer%2C+T+J+L">Thomas J. L. de Boer</a>, <a href="/search/astro-ph?searchtype=author&query=Gruendl%2C+R+A">Robert A. Gruendl</a>, <a href="/search/astro-ph?searchtype=author&query=Monelli%2C+M">Matteo Monelli</a>, <a href="/search/astro-ph?searchtype=author&query=Munoz%2C+R+R">Ricardo R. Munoz</a> , et al. (10 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="2011.13943v1-abstract-short" style="display: inline;"> The Large and Small Magellanic Clouds (LMC and SMC) are the largest satellite galaxies of the Milky Way and close enough to allow for a detailed exploration of their structure and formation history. The Survey of the MAgellanic Stellar History (SMASH) is a community Dark Energy Camera (DECam) survey of the Magellanic Clouds using $\sim$50 nights to sample over $\sim$2400 deg$^2$ centered on the Cl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.13943v1-abstract-full').style.display = 'inline'; document.getElementById('2011.13943v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.13943v1-abstract-full" style="display: none;"> The Large and Small Magellanic Clouds (LMC and SMC) are the largest satellite galaxies of the Milky Way and close enough to allow for a detailed exploration of their structure and formation history. The Survey of the MAgellanic Stellar History (SMASH) is a community Dark Energy Camera (DECam) survey of the Magellanic Clouds using $\sim$50 nights to sample over $\sim$2400 deg$^2$ centered on the Clouds at $\sim$20% filling factor (but with contiguous coverage in the central regions) and to depths of $\sim$24th mag in $ugriz$. The primary goals of SMASH are to map out the extended stellar peripheries of the Clouds and uncover their complicated interaction and accretion history as well as to derive spatially-resolved star formation histories of the central regions and create a "movie" of their past star formation. Here we announce the second SMASH public data release (DR2), which contains all 197 fully-calibrated DECam fields including the main body fields in the central regions. The DR2 data are available through the Astro Data Lab hosted by the NSF's National Optical-Infrared Astronomy Research Laboratory. We highlight three science cases that make use of the SMASH DR2 data and will be published in the future: (1) preliminary star formation histories of the LMC; (2) the search for Magellanic star clusters using citizen scientists; and, (3) photometric metallicities of Magellanic Cloud stars using the DECam $u$-band. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.13943v1-abstract-full').style.display = 'none'; document.getElementById('2011.13943v1-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 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 9 figures. Accepted for publication in 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/2011.09395">arXiv:2011.09395</a> <span> [<a href="https://arxiv.org/pdf/2011.09395">pdf</a>, <a href="https://arxiv.org/format/2011.09395">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/abcb83">10.3847/2041-8213/abcb83 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discovery of Magellanic Stellar Debris in the H3 Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zaritsky%2C+D">Dennis Zaritsky</a>, <a href="/search/astro-ph?searchtype=author&query=Conroy%2C+C">Charlie Conroy</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+R+P">Rohan P. Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Cargile%2C+P+A">Phillip A. Cargile</a>, <a href="/search/astro-ph?searchtype=author&query=Putman%2C+M">Mary Putman</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Bonaca%2C+A">Ana Bonaca</a>, <a href="/search/astro-ph?searchtype=author&query=Caldwell%2C+N">Nelson Caldwell</a>, <a href="/search/astro-ph?searchtype=author&query=Han%2C+J+J">Jiwon Jesse Han</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+B+D">Benjamin D. Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Speagle%2C+J+S">Joshua S. Speagle</a>, <a href="/search/astro-ph?searchtype=author&query=Ting%2C+Y">Yuan-Sen Ting</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="2011.09395v1-abstract-short" style="display: inline;"> We report the discovery of 15 stars in the H3 survey that lie, in projection, near the tip of the trailing gaseous Magellanic Stream (MS). The stars have Galactocentric velocities $< -155$ km s$^{-1}$, Galactocentric distances of $\approx 40$ to 80 kpc (increasing along the MS), and [Fe/H] consistent with that of stars in the Small Magellanic Cloud. These 15 stars comprise 94% (15 of 16) of the H3… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.09395v1-abstract-full').style.display = 'inline'; document.getElementById('2011.09395v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.09395v1-abstract-full" style="display: none;"> We report the discovery of 15 stars in the H3 survey that lie, in projection, near the tip of the trailing gaseous Magellanic Stream (MS). The stars have Galactocentric velocities $< -155$ km s$^{-1}$, Galactocentric distances of $\approx 40$ to 80 kpc (increasing along the MS), and [Fe/H] consistent with that of stars in the Small Magellanic Cloud. These 15 stars comprise 94% (15 of 16) of the H3 observed stars to date that have $R_{GAL} > 37.5$ kpc, $-$350 km s$^{-1} < V_{GSR} < -155$ km s$^{-1}$, and are not associated with the Sagittarius Stream. They represent a unique portion of the Milky Way's outer halo phase space distribution function and confirm that unrelaxed structure is detectable even at radii where H3 includes only a few hundred stars. Due to their statistical excess, their close association with the MS and H I compact clouds in the same region, both in position and velocity space, and their plausible correspondence with tidal debris in a published simulation, we identify these stars as debris of past Magellanic Cloud encounters. These stars are evidence for a stellar component of the tidal debris field far from the Clouds themselves and provide unique constraints on the interaction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.09395v1-abstract-full').style.display = 'none'; document.getElementById('2011.09395v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in ApJL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.00816">arXiv:2010.00816</a> <span> [<a href="https://arxiv.org/pdf/2010.00816">pdf</a>, <a href="https://arxiv.org/format/2010.00816">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac0b44">10.3847/1538-4357/ac0b44 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantifying the impact of the Large Magellanic Cloud on the structure of the Milky Way's dark matter halo using Basis Function Expansions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicolas Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Laporte%2C+C+F+P">Chervin F. P. Laporte</a>, <a href="/search/astro-ph?searchtype=author&query=Price-Whelan%2C+A+M">Adrian M. Price-Whelan</a>, <a href="/search/astro-ph?searchtype=author&query=Cunningham%2C+E+C">Emily C. Cunningham</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+K+V">Kathryn V. Johnston</a>, <a href="/search/astro-ph?searchtype=author&query=Weinberg%2C+M+D">Martin D. Weinberg</a>, <a href="/search/astro-ph?searchtype=author&query=Gomez%2C+F+A">Facundo A. Gomez</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2010.00816v2-abstract-short" style="display: inline;"> Indications of disequilibrium throughout the Milky Way (MW) highlight the need for compact,flexible, non-parametric descriptions of phase--space distributions of galaxies. We present a new representation of the current Dark Matter (DM) distribution and potential derived from N-body simulations of the Milky Way and Large Magellanic Cloud (LMC) system using Basis Function Expansions (BFEs). We incor… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.00816v2-abstract-full').style.display = 'inline'; document.getElementById('2010.00816v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.00816v2-abstract-full" style="display: none;"> Indications of disequilibrium throughout the Milky Way (MW) highlight the need for compact,flexible, non-parametric descriptions of phase--space distributions of galaxies. We present a new representation of the current Dark Matter (DM) distribution and potential derived from N-body simulations of the Milky Way and Large Magellanic Cloud (LMC) system using Basis Function Expansions (BFEs). We incorporate methods to maximize the physical signal in the representation. As a result, the simulations of $10^8$ DM particles representing the MW--LMC system can be described by 354 coefficients. We find that the LMC induces asymmetric perturbations (odd l, m) to the MW's halo, which are not well-described by oblate, prolate, or triaxial halos. Furthermore, the energy in high-order even modes (l,m $\geq$ 2) is similar to average triaxial halos found in cosmological simulations. As such, the response of the MW's halo to the LMC must be accounted for in order to recover the imprints of its assembly history. The LMC causes the outer halo ($\geq$ 30 kpc) to shift from the disk center of mass (COM) by $\sim$15-25 kpc at present day, manifesting as a dipole in the BFE and in the radial velocities of halo stars. The shift depends on the LMC's infall mass, the distortion of the LMC's halo and the MW halo response. Within 30 kpc, halo tracers are expected to orbit the COM of the MW's disk, regardless of LMC infall mass. The LMC's halo is also distorted by MW tides, we discuss the implications for its mass loss and the subsequent effects on current Magellanic satellites. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.00816v2-abstract-full').style.display = 'none'; document.getElementById('2010.00816v2-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, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 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">35 pages, 25 figures, Accepted for publication in ApJ. 3d movie can be found here: https://vimeo.com/546207117</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2008.06055">arXiv:2008.06055</a> <span> [<a href="https://arxiv.org/pdf/2008.06055">pdf</a>, <a href="https://arxiv.org/format/2008.06055">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/abaf49">10.3847/1538-4357/abaf49 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> HST Proper Motions of NGC 147 and NGC 185: Orbital Histories and Test of Dynamically Coherent Andromeda Satellite Plane </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sohn%2C+S+T">Sangmo Tony Sohn</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Fardal%2C+M+A">Mark A. Fardal</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Geha%2C+M">Marla Geha</a>, <a href="/search/astro-ph?searchtype=author&query=Guhathakurta%2C+P">Puragra Guhathakurta</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2008.06055v1-abstract-short" style="display: inline;"> We present the first proper motion (PM) measurements for the dwarf elliptical galaxies NGC 147 and NGC 185, two satellite galaxies of M31, using multi-epoch HST imaging data with time baselines of $\sim 8$ years. For each galaxy, we take an error-weighted average of measurements from HST ACS/WFC and WFC3/UVIS to determine the PMs. Our final results for the PMs are… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.06055v1-abstract-full').style.display = 'inline'; document.getElementById('2008.06055v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2008.06055v1-abstract-full" style="display: none;"> We present the first proper motion (PM) measurements for the dwarf elliptical galaxies NGC 147 and NGC 185, two satellite galaxies of M31, using multi-epoch HST imaging data with time baselines of $\sim 8$ years. For each galaxy, we take an error-weighted average of measurements from HST ACS/WFC and WFC3/UVIS to determine the PMs. Our final results for the PMs are $(渭_\mathrm{W}, 渭_\mathrm{N})_\mathrm{N147} = (-0.0232, 0.0378) \pm (0.0143, 0.0146)\,\mathrm{mas}\,\mathrm{yr}^{-1}$ for NGC 147, and $(渭_\mathrm{W}, 渭_\mathrm{N})_\mathrm{N185} = (-0.0242, 0.0058) \pm (0.0141, 0.0147)\,\mathrm{mas}\,\mathrm{yr}^{-1}$ for NGC 185. The 2-dimensional direction of motion for NGC 147 about M31 is found to be aligned with its tidal tails. The 3-d positions and velocities of both galaxies are transformed into a common M31-centric coordinate system to study the detailed orbital histories of the combined M31+NGC 147+NGC 185 system via numerical orbit integration. We find that NGC 147 (NGC 185) had its closest passage to M31 0.3-0.5~Gyr ($\gtrsim 1.6$~Gyr) within the past 6 Gyr at distances of $\sim 70$ kpc (70-260 kpc). The pericentric times of NGC 147/NGC 185 correlate qualitatively well with the presence/absence of tidal tails seen around the galaxies. Our PMs show that the orbital poles of NGC 147, and also NGC 185 albeit to a lesser degree, agree within the uncertainties with the normal of the Great Plane of Andromeda (GPoA). These are the first measurements of the 3-d angular momentum vector of any satellite identified as original GPoA members. Our results strengthen the hypothesis that the GPoA may be a dynamically coherent entity. We revisit previous claims that NGC 147 and NGC 185 are binary galaxies and conclude that it is very unlikely the two galaxies were ever gravitationally bound to each other. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.06055v1-abstract-full').style.display = 'none'; document.getElementById('2008.06055v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 August, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 9 figures, 4 tables, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2006.10759">arXiv:2006.10759</a> <span> [<a href="https://arxiv.org/pdf/2006.10759">pdf</a>, <a href="https://arxiv.org/format/2006.10759">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/10.1051/0004-6361/202038392">10.1051/0004-6361/202038392 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Large Magellanic Cloud stellar content with SMASH: I. Assessing the stability of the Magellanic spiral arms </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ruiz-Lara%2C+T">T. Ruiz-Lara</a>, <a href="/search/astro-ph?searchtype=author&query=Gallart%2C+C">C. Gallart</a>, <a href="/search/astro-ph?searchtype=author&query=Monelli%2C+M">M. Monelli</a>, <a href="/search/astro-ph?searchtype=author&query=Nidever%2C+D">D. Nidever</a>, <a href="/search/astro-ph?searchtype=author&query=Dorta%2C+A">A. Dorta</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Y. Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Olsen%2C+K">K. Olsen</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">G. Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Bernard%2C+E+J">E. J. Bernard</a>, <a href="/search/astro-ph?searchtype=author&query=Cassisi%2C+S">S. Cassisi</a>, <a href="/search/astro-ph?searchtype=author&query=Massana%2C+P">P. Massana</a>, <a href="/search/astro-ph?searchtype=author&query=No%C3%ABl%2C+N+E+D">N. E. D. No毛l</a>, <a href="/search/astro-ph?searchtype=author&query=P%C3%A9rez%2C+I">I. P茅rez</a>, <a href="/search/astro-ph?searchtype=author&query=Rusakov%2C+V">V. Rusakov</a>, <a href="/search/astro-ph?searchtype=author&query=Cioni%2C+M+-+L">M. -R. L. Cioni</a>, <a href="/search/astro-ph?searchtype=author&query=Majewski%2C+S+R">S. R. Majewski</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">R. P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Mart%C3%ADnez-Delgado%2C+D">D. Mart铆nez-Delgado</a>, <a href="/search/astro-ph?searchtype=author&query=Monachesi%2C+A">A. Monachesi</a>, <a href="/search/astro-ph?searchtype=author&query=Monteagudo%2C+L">L. Monteagudo</a>, <a href="/search/astro-ph?searchtype=author&query=Mu%C3%B1oz%2C+R+R">R. R. Mu帽oz</a>, <a href="/search/astro-ph?searchtype=author&query=Stringfellow%2C+G+S">G. S. Stringfellow</a>, <a href="/search/astro-ph?searchtype=author&query=Surot%2C+F">F. Surot</a>, <a href="/search/astro-ph?searchtype=author&query=Vivas%2C+A+K">A. K. Vivas</a>, <a href="/search/astro-ph?searchtype=author&query=Walker%2C+A+R">A. R. Walker</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="2006.10759v1-abstract-short" style="display: inline;"> The Large Magellanic Cloud (LMC) is the closest and most studied example of an irregular galaxy. Among its principal defining morphological features, its off-centred bar and single spiral arm stand out, defining a whole family of galaxies known as the Magellanic spirals (Sm). These structures are thought to be triggered by tidal interactions and possibly maintained via gas accretion. However, it i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.10759v1-abstract-full').style.display = 'inline'; document.getElementById('2006.10759v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.10759v1-abstract-full" style="display: none;"> The Large Magellanic Cloud (LMC) is the closest and most studied example of an irregular galaxy. Among its principal defining morphological features, its off-centred bar and single spiral arm stand out, defining a whole family of galaxies known as the Magellanic spirals (Sm). These structures are thought to be triggered by tidal interactions and possibly maintained via gas accretion. However, it is still unknown whether they are long-lived stable structures. In this work, by combining photometry that reaches down to the oldest main sequence turn-off in the colour-magnitude diagrams (CMD, up to a distance of $\sim$4.4 kpc from the LMC centre) from the SMASH survey and CMD fitting techniques, we find compelling evidence supporting the long-term stability of the LMC spiral arm, dating the origin of this structure to more than 2~Gyr ago. The evidence suggests that the close encounter between the LMC and the Small Magellanic Cloud (SMC) that produced the gaseous Magellanic Stream and its Leading Arm (LA) also triggered the formation of the LMC's spiral arm. Given the mass difference between the Clouds and the notable consequences of this interaction, we can speculate that this should have been one of their closest encounters. These results set important constraints on the timing of LMC-SMC collisions, as well as on the physics behind star formation induced by tidal encounters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.10759v1-abstract-full').style.display = 'none'; document.getElementById('2006.10759v1-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 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 3 figures, accepted for publication in A&A letters</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 639, L3 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2006.08621">arXiv:2006.08621</a> <span> [<a href="https://arxiv.org/pdf/2006.08621">pdf</a>, <a href="https://arxiv.org/format/2006.08621">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab9b88">10.3847/1538-4357/ab9b88 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantifying the Stellar Halo's Response to the LMC's Infall with Spherical Harmonics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cunningham%2C+E+C">Emily C. Cunningham</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicolas Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Deason%2C+A+J">Alis J. Deason</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+K+V">Kathryn V. Johnston</a>, <a href="/search/astro-ph?searchtype=author&query=Erkal%2C+D">Denis Erkal</a>, <a href="/search/astro-ph?searchtype=author&query=Laporte%2C+C+F+P">Chervin F. P. Laporte</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Luger%2C+R">Rodrigo Luger</a>, <a href="/search/astro-ph?searchtype=author&query=Sanderson%2C+R+E">Robyn E. Sanderson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2006.08621v1-abstract-short" style="display: inline;"> The vast majority of the mass in the Milky Way (MW) is in dark matter (DM); we therefore cannot directly observe the MW mass distribution, and have to use tracer populations in order to infer properties of the MW DM halo. However, MW halo tracers do not only feel the gravitational influence of the MW itself. Tracers can also be affected by MW satellites; Garavito-Camargo et al. (2019) (hereafter G… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.08621v1-abstract-full').style.display = 'inline'; document.getElementById('2006.08621v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.08621v1-abstract-full" style="display: none;"> The vast majority of the mass in the Milky Way (MW) is in dark matter (DM); we therefore cannot directly observe the MW mass distribution, and have to use tracer populations in order to infer properties of the MW DM halo. However, MW halo tracers do not only feel the gravitational influence of the MW itself. Tracers can also be affected by MW satellites; Garavito-Camargo et al. (2019) (hereafter GC19) demonstrate that the Large Magellanic Cloud (LMC) induces a density wake in the MW DM, resulting in large scale kinematic patterns in the MW stellar halo. In this work, we use spherical harmonic expansion (SHE) of the velocity fields of simulated stellar halos in an effort to disentangle perturbations on large scales (e.g., due to the LMC itself as well as the LMC-induced DM wake) and small scales (due to substructure). Using the GC19 simulations, we demonstrate how the different terms in the SHE of the stellar velocity field reflect the different wake components, and show that these signatures are a strong function of the LMC mass. An exploration of model halos built from accreted dwarfs Bullock & Johnston (2005) suggests that stellar debris from massive, recent accretion events can produce much more power in the velocity angular power spectra than the perturbation from the LMC-induced wake. We therefore consider two models for the Sagittarius (Sgr) stream -- the most recent, massive accretion event in the MW apart from the LMC -- and find that the angular power on large scales is generally dominated by the LMC-induced wake, even when Sgr is included. We conclude that SHE of the MW stellar halo velocity field may therefore be a useful tool in quantifying the response of the MW DM halo to the LMC's infall. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.08621v1-abstract-full').style.display = 'none'; document.getElementById('2006.08621v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">25 pages, 13 figures. Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.01746">arXiv:2001.01746</a> <span> [<a href="https://arxiv.org/pdf/2001.01746">pdf</a>, <a href="https://arxiv.org/format/2001.01746">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab7b75">10.3847/1538-4357/ab7b75 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Orbital Histories of Magellanic Satellites Using Gaia DR2 Proper Motions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicolas Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Weisz%2C+D+R">Daniel R. Weisz</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Boylan-Kolchin%2C+M">Michael Boylan-Kolchin</a>, <a href="/search/astro-ph?searchtype=author&query=Pawlowski%2C+M+S">Marcel S. Pawlowski</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3mez%2C+F+A">Facundo A. G贸mez</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="2001.01746v2-abstract-short" style="display: inline;"> With the release of Gaia DR2, it is now possible to measure the proper motions (PMs) of the lowest mass, ultra-faint satellite galaxies in the Milky Way's (MW) halo for the first time. Many of these faint satellites are posited to have been accreted as satellites of the Magellanic Clouds (MCs). Using their 6-dimensional phase space information, we calculate the orbital histories of 13 ultra-faint… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.01746v2-abstract-full').style.display = 'inline'; document.getElementById('2001.01746v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.01746v2-abstract-full" style="display: none;"> With the release of Gaia DR2, it is now possible to measure the proper motions (PMs) of the lowest mass, ultra-faint satellite galaxies in the Milky Way's (MW) halo for the first time. Many of these faint satellites are posited to have been accreted as satellites of the Magellanic Clouds (MCs). Using their 6-dimensional phase space information, we calculate the orbital histories of 13 ultra-faint satellites and five classical dwarf spheroidals in a combined MW+LMC+SMC potential to determine which galaxies are dynamically associated with the MCs. These 18 galaxies are separated into four classes: i.) long-term Magellanic satellites that have been bound to the MCs for at least the last two consecutive orbits around the MCs (Carina 2, Carina 3, Horologium 1, Hydrus 1); ii.) Magellanic satellites that were recently captured by the MCs $<$ 1 Gyr ago (Reticulum 2, Phoenix 2); iii.) MW satellites that have interacted with the MCs (Sculptor 1, Tucana 3, Segue 1); and iv.) MW satellites (Aquarius 2, Canes Venatici 2, Crater 2, Draco 1, Draco 2, Hydra 2, Carina, Fornax, Ursa Minor). Results are reported for a range of MW and LMC masses. Contrary to previous work, we find no dynamical association between Carina, Fornax, and the MCs. Finally, we determine that the addition of the SMC's gravitational potential affects the longevity of satellites as members of the Magellanic system (long-term versus recently captured), but it does not change the total number of Magellanic satellites. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.01746v2-abstract-full').style.display = 'none'; document.getElementById('2001.01746v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 March, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 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">32 pages, 11 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/1909.04140">arXiv:1909.04140</a> <span> [<a href="https://arxiv.org/pdf/1909.04140">pdf</a>, <a href="https://arxiv.org/format/1909.04140">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1475-7516/2019/11/013">10.1088/1475-7516/2019/11/013 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The highest-speed local dark matter particles come from the Large Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+A">Annika Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicolas Garavito-Camargo</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="1909.04140v1-abstract-short" style="display: inline;"> Using N-body simulations of the Large Magellanic Cloud (LMC's) passage through the Milky Way (MW), tailored to reproduce observed kinematic properties of both galaxies, we show that the high-speed tail of the Solar Neighborhood dark matter distribution is overwhelmingly of LMC origin. Two populations contribute at high speeds: 1) Particles that were once bound to the LMC, and 2) MW halo particles… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.04140v1-abstract-full').style.display = 'inline'; document.getElementById('1909.04140v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.04140v1-abstract-full" style="display: none;"> Using N-body simulations of the Large Magellanic Cloud (LMC's) passage through the Milky Way (MW), tailored to reproduce observed kinematic properties of both galaxies, we show that the high-speed tail of the Solar Neighborhood dark matter distribution is overwhelmingly of LMC origin. Two populations contribute at high speeds: 1) Particles that were once bound to the LMC, and 2) MW halo particles that have been accelerated owing to the response of the halo to the recent passage of the LMC. These particles reach speeds of 700-900 km/s with respect to the Earth, above the local escape speed of the MW. The high-speed particles follow trajectories similar to the Solar reflex motion, with peak velocities reached in June. For low-mass dark matter, these high-speed particles can dominate the signal in direct-detection experiments, extending the reach of the experiments to lower mass and elastic scattering cross sections even with existing data sets. Our study shows that even non-disrupted MW satellite galaxies can leave a significant dark-matter footprint in the Solar Neighborhood. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.04140v1-abstract-full').style.display = 'none'; document.getElementById('1909.04140v1-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 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">Submitted to JCAP, comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.04460">arXiv:1907.04460</a> <span> [<a href="https://arxiv.org/pdf/1907.04460">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"> Astro2020: Training the Future Generation of Computational Researchers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Huppenkothen%2C+D">Daniela Huppenkothen</a>, <a href="/search/astro-ph?searchtype=author&query=Lloyd-Ronning%2C+N">Nicole Lloyd-Ronning</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+E">Evan Schneider</a>, <a href="/search/astro-ph?searchtype=author&query=Behroozi%2C+P">Peter Behroozi</a>, <a href="/search/astro-ph?searchtype=author&query=Burkhart%2C+B">Blakesley Burkhart</a>, <a href="/search/astro-ph?searchtype=author&query=Chan%2C+C+K">C. K. Chan</a>, <a href="/search/astro-ph?searchtype=author&query=Jacobson%2C+S+A">Seth A. Jacobson</a>, <a href="/search/astro-ph?searchtype=author&query=Morrison%2C+S">Sarah Morrison</a>, <a href="/search/astro-ph?searchtype=author&query=Nam%2C+H+A">Hai Ah Nam</a>, <a href="/search/astro-ph?searchtype=author&query=Naoz%2C+S">Smadar Naoz</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+A">Annika Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Ramirez-Ruiz%2C+E">Enrico Ramirez-Ruiz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1907.04460v1-abstract-short" style="display: inline;"> The current disparity in computational knowledge is a critical hindrance to the diversity and success of the field. Recommendations are outlined for policies and funding models to enable the growth and retention of a new generation of computational researchers that reflect the demographics of the undergraduate population in Astronomy and Physics. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.04460v1-abstract-full" style="display: none;"> The current disparity in computational knowledge is a critical hindrance to the diversity and success of the field. Recommendations are outlined for policies and funding models to enable the growth and retention of a new generation of computational researchers that reflect the demographics of the undergraduate population in Astronomy and Physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.04460v1-abstract-full').style.display = 'none'; document.getElementById('1907.04460v1-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, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Astro2020 APC White Paper: State of the Profession Consideration</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.02264">arXiv:1907.02264</a> <span> [<a href="https://arxiv.org/pdf/1907.02264">pdf</a>, <a href="https://arxiv.org/format/1907.02264">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/10.1051/0004-6361/201936021">10.1051/0004-6361/201936021 <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 a shell of young stars in the outskirts of the Small Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Martinez-Delgado%2C+D">David Martinez-Delgado</a>, <a href="/search/astro-ph?searchtype=author&query=Vivas%2C+A+K">A. Katherina Vivas</a>, <a href="/search/astro-ph?searchtype=author&query=Grebel%2C+E+K">Eva K. Grebel</a>, <a href="/search/astro-ph?searchtype=author&query=Gallart%2C+C">Carme Gallart</a>, <a href="/search/astro-ph?searchtype=author&query=Pieres%2C+A">Adriano Pieres</a>, <a href="/search/astro-ph?searchtype=author&query=Bell%2C+C+P+M">Cameron P. M. Bell</a>, <a href="/search/astro-ph?searchtype=author&query=Zivick%2C+P">Paul Zivick</a>, <a href="/search/astro-ph?searchtype=author&query=Lemasle%2C+B">Bertrand Lemasle</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+L+C">L. Clifton Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Carballo-Bello%2C+J+A">Julio A. Carballo-Bello</a>, <a href="/search/astro-ph?searchtype=author&query=Noel%2C+N+E+D">Noelia E. D. Noel</a>, <a href="/search/astro-ph?searchtype=author&query=Cioni%2C+M+L">Maria-Rosa L. Cioni</a>, <a href="/search/astro-ph?searchtype=author&query=Choi%2C+Y">Yumi Choi</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Schmidt%2C+J">Judy Schmidt</a>, <a href="/search/astro-ph?searchtype=author&query=Zaritsky%2C+D">Dennis Zaritsky</a>, <a href="/search/astro-ph?searchtype=author&query=Gruendl%2C+R+A">Robert A. Gruendl</a>, <a href="/search/astro-ph?searchtype=author&query=Seibert%2C+M">Mark Seibert</a>, <a href="/search/astro-ph?searchtype=author&query=Nidever%2C+D">David Nidever</a>, <a href="/search/astro-ph?searchtype=author&query=Monteagudo%2C+L">Laura Monteagudo</a>, <a href="/search/astro-ph?searchtype=author&query=Monelli%2C+M">Mateo Monelli</a>, <a href="/search/astro-ph?searchtype=author&query=Hubl%2C+B">Bernhard Hubl</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R">Roeland van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Ballesteros%2C+F+J">Fernando J. Ballesteros</a>, <a href="/search/astro-ph?searchtype=author&query=Stringfellow%2C+G">Guy Stringfellow</a> , et al. (13 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1907.02264v2-abstract-short" style="display: inline;"> Understanding the evolutionary history of the Magellanic Clouds requires an in-depth exploration and characterization of the stellar content in their outer regions, which ultimately are key to tracing the epochs and nature of past interactions. We present new deep images of a shell-like over-density of stars in the outskirts of the Small Magellanic Cloud (SMC). The shell, also detected in photogra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.02264v2-abstract-full').style.display = 'inline'; document.getElementById('1907.02264v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.02264v2-abstract-full" style="display: none;"> Understanding the evolutionary history of the Magellanic Clouds requires an in-depth exploration and characterization of the stellar content in their outer regions, which ultimately are key to tracing the epochs and nature of past interactions. We present new deep images of a shell-like over-density of stars in the outskirts of the Small Magellanic Cloud (SMC). The shell, also detected in photographic plates dating back to the fifties, is located at ~1.9 degr from the center of the SMC in the north-east direction.The structure and stellar content of this feature were studied with multi-band, optical data from the Survey of the MAgellanic Stellar History (SMASH) carried out with the Dark Energy Camera on the Blanco Telescope at Cerro Tololo Inter-American Observatory. We also investigate the kinematic of the stars in the shell using the Gaia Data Release 2. The shell is composed of a young population with an age ~ 150 Myr, with no contribution from an old population. Thus, it is hard to explain its origin as the remnant of a tidally disrupted stellar system. The spatial distribution of the young main-sequence stars shows a rich sub-structure, with a spiral arm-like feature emanating from the main shell and a separated small arc of young stars close to the globular cluster NGC 362. We find that the absolute g-band magnitude of the shell is M_{g,shell} = -10.78+/- 0.02, with a surface brightness of mu_{g,shell} = 25.81+/- 0.01 mag/arcsec^{2}. We have not found any evidence that this feature is of tidal origin or a bright part of a spiral arm-like structure. Instead, we suggest that the shell formed in a recent star formation event, likely triggered by an interaction with the Large Magellanic Cloud and/or the Milky Way, ~150 Myr ago. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.02264v2-abstract-full').style.display = 'none'; document.getElementById('1907.02264v2-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 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 14 figures, submitted to Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 631, A98 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.05409">arXiv:1905.05409</a> <span> [<a href="https://arxiv.org/pdf/1905.05409">pdf</a>, <a href="https://arxiv.org/format/1905.05409">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab1eaa">10.3847/1538-4357/ab1eaa <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Probing the assembly of dwarf galaxies through cosmic time with damped Lyman-$伪$ absorption spectroscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Jeon%2C+M">Myoungwon Jeon</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Bromm%2C+V">Volker Bromm</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1905.05409v1-abstract-short" style="display: inline;"> We investigate the absorption features associated with a gas-rich dwarf galaxy using cosmological hydrodynamics simulations. Our goal is to explore whether the progenitors of the lowest mass dwarf galaxies known to harbor neutral hydrogen today (M_star~10^6 solar mass, M_halo=4x10^9 solar mass) could possibly be detected as Damped Lyman-alpha Absorbers (DLAs) over cosmic time. We trace the evoluti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.05409v1-abstract-full').style.display = 'inline'; document.getElementById('1905.05409v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.05409v1-abstract-full" style="display: none;"> We investigate the absorption features associated with a gas-rich dwarf galaxy using cosmological hydrodynamics simulations. Our goal is to explore whether the progenitors of the lowest mass dwarf galaxies known to harbor neutral hydrogen today (M_star~10^6 solar mass, M_halo=4x10^9 solar mass) could possibly be detected as Damped Lyman-alpha Absorbers (DLAs) over cosmic time. We trace the evolution of a single dwarf galaxy, pre-selected to contain DLAs, from the era of the first metal-free, so-called Population~III (Pop~III), stars, down to z=0, thus allowing us to study the metal enrichment history of DLAs associated with the simulated galaxy. We find that the progenitors of the simulated dwarf are expected to be seen for most of their evolution as DLAs that are contaminated by normal, Population~II, stars. The time period during which DLAs are only metal-enriched by Pop~III stars, on the other hand, is likely very brief, confined to high redshifts, z~6. The susceptibility of the dwarfs to the external UV radiation background allows them to preserve neutral gas only at the centre (a few ~100 pc). This results in a small probability that the simulated dwarf would be observed as a DLA. This study suggests that DLAs are unlikely to be hosted in the lowest mass dwarfs that can harbor neutral gas (M_halo~ 4x10^9 solar mass), below which neutral gas is unlikely to exist. However, this study does illustrate that, when detected, absorption lines provide a powerful method for probing ISM conditions inside the smallest dwarf galaxies at intermediate to high redshifts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.05409v1-abstract-full').style.display = 'none'; document.getElementById('1905.05409v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 14 figures, Accepted for Publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1902.05089">arXiv:1902.05089</a> <span> [<a href="https://arxiv.org/pdf/1902.05089">pdf</a>, <a href="https://arxiv.org/format/1902.05089">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab32eb">10.3847/1538-4357/ab32eb <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Hunting for the Dark Matter Wake Induced by the Large Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Garavito-Camargo%2C+N">Nicolas Garavito-Camargo</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Laporte%2C+C+F+P">Chervin F. P Laporte</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+K+V">Kathryn V. Johnston</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3mez%2C+F+A">Facundo A. G贸mez</a>, <a href="/search/astro-ph?searchtype=author&query=Watkins%2C+L+L">Laura L. Watkins</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="1902.05089v2-abstract-short" style="display: inline;"> Satellite galaxies are predicted to generate gravitational density wakes as they orbit within the dark matter (DM) halos of their hosts, causing their orbits to decay over time. The recent infall of the Milky Way's (MW) most massive satellite galaxy, the Large Magellanic Cloud (LMC), affords us the unique opportunity to study this process in action. In this work, we present high-resolution (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.05089v2-abstract-full').style.display = 'inline'; document.getElementById('1902.05089v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1902.05089v2-abstract-full" style="display: none;"> Satellite galaxies are predicted to generate gravitational density wakes as they orbit within the dark matter (DM) halos of their hosts, causing their orbits to decay over time. The recent infall of the Milky Way's (MW) most massive satellite galaxy, the Large Magellanic Cloud (LMC), affords us the unique opportunity to study this process in action. In this work, we present high-resolution ($m_{dm} = 4 \times 10^4 M_{\odot}$ ) N-body simulations of the MW-LMC interaction over the past 2 Gyr. We quantify the impact of the LMC's passage on the density and kinematics of the MW's DM halo and the observability of these structures in the MW's stellar halo. The LMC is found to generate pronounced Local and Global wakes in both the DM and stellar halos, leads to both local overdensities and distinct kinematic patterns that should be observable with ongoing and future surveys. Specifically, the Global Wake will result in redshifted radial velocities of stars in the North and blueshifts in the South, at distances larger than 45 kpc. The Local Wake traces the orbital path of the LMC through the halo (50-200 kpc), resulting in a stellar overdensity with a distinct, tangential kinematic pattern that persists to the present day. The detection of the MW's halo response will constrain: the infall mass of the LMC and its orbital trajectory, the mass of the MW, and it may inform us about the nature of the dark matter particle itself. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.05089v2-abstract-full').style.display = 'none'; document.getElementById('1902.05089v2-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, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 February, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">41 pages, 27 figures. Accepted to ApJ. Some terminology was changed. High-resolution images and figures can be found at https://bit.ly/2S25YzC</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1811.09318">arXiv:1811.09318</a> <span> [<a href="https://arxiv.org/pdf/1811.09318">pdf</a>, <a href="https://arxiv.org/format/1811.09318">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab0554">10.3847/1538-4357/ab0554 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Proper Motion Field Along the Magellanic Bridge: a New Probe of the LMC-SMC Interaction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zivick%2C+P">Paul Zivick</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Sohn%2C+S+T">Sangmo Tony Sohn</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=del+Pino%2C+A">Andr茅s del Pino</a>, <a href="/search/astro-ph?searchtype=author&query=Linden%2C+S+T">Sean T. Linden</a>, <a href="/search/astro-ph?searchtype=author&query=Fritz%2C+T+K">Tobias K. Fritz</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+J">J. Anderson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1811.09318v2-abstract-short" style="display: inline;"> We present the first detailed kinematic analysis of the proper motions (PMs) of stars in the Magellanic Bridge, from both the \textit{Gaia} Data Release 2 catalog and from \textit{Hubble Space Telescope} Advanced Camera for Surveys data. For the \textit{Gaia} data, we identify and select two populations of stars in the Bridge region, young main sequence (MS) and red giant stars. The spatial locati… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.09318v2-abstract-full').style.display = 'inline'; document.getElementById('1811.09318v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.09318v2-abstract-full" style="display: none;"> We present the first detailed kinematic analysis of the proper motions (PMs) of stars in the Magellanic Bridge, from both the \textit{Gaia} Data Release 2 catalog and from \textit{Hubble Space Telescope} Advanced Camera for Surveys data. For the \textit{Gaia} data, we identify and select two populations of stars in the Bridge region, young main sequence (MS) and red giant stars. The spatial locations of the stars are compared against the known H {\small I} gas structure, finding a correlation between the MS stars and the H {\small I} gas. In the \textit{Hubble Space Telescope} fields our signal comes mainly from an older MS and turn-off population, and the proper motion baselines range between $\sim 4$ and 13 years. The PMs of these different populations are found to be consistent with each other, as well as across the two telescopes. When the absolute motion of the Small Magellanic Cloud is subtracted out, the residual Bridge motions display a general pattern of pointing away from the Small Magellanic Cloud towards the Large Magellanic Cloud. We compare in detail the kinematics of the stellar samples against numerical simulations of the interactions between the Small and Large Magellanic Clouds, and find general agreement between the kinematics of the observed populations and a simulation in which the Clouds have undergone a recent direct collision. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.09318v2-abstract-full').style.display = 'none'; document.getElementById('1811.09318v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 February, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 10 figures, 2 tables, submitted to ApJ, accepted February 8th, 2019</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1810.06596">arXiv:1810.06596</a> <span> [<a href="https://arxiv.org/pdf/1810.06596">pdf</a>, <a href="https://arxiv.org/format/1810.06596">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/aae892">10.3847/2041-8213/aae892 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Oey%2C+M+S">M. S. Oey</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+J+D">J. Dorigo Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Zivick%2C+P">P. Zivick</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">G. Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Januszewski%2C+H+C">H. C. Januszewski</a>, <a href="/search/astro-ph?searchtype=author&query=Moe%2C+M">M. Moe</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">N. Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</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="1810.06596v2-abstract-short" style="display: inline;"> We use GAIA DR2 proper motions of the RIOTS4 field OB stars in the Small Magellanic Cloud (SMC) to study the kinematics of runaway stars. The data reveal that the SMC Wing has a systemic peculiar motion relative to the SMC Bar of (v_RA, v_Dec) = (62 +/-7, -18+/-5) km/s and relative radial velocity +4.5 +/- 5.0 km/s. This unambiguously demonstrates that these two regions are kinematically distinct:… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.06596v2-abstract-full').style.display = 'inline'; document.getElementById('1810.06596v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1810.06596v2-abstract-full" style="display: none;"> We use GAIA DR2 proper motions of the RIOTS4 field OB stars in the Small Magellanic Cloud (SMC) to study the kinematics of runaway stars. The data reveal that the SMC Wing has a systemic peculiar motion relative to the SMC Bar of (v_RA, v_Dec) = (62 +/-7, -18+/-5) km/s and relative radial velocity +4.5 +/- 5.0 km/s. This unambiguously demonstrates that these two regions are kinematically distinct: the Wing is moving away from the Bar, and towards the Large Magellanic Cloud with a 3-D velocity of 64 +/- 10 km/s. This is consistent with models for a recent, direct collision between the Clouds. We present transverse velocity distributions for our field OB stars, confirming that unbound runaways comprise on the order of half our sample, possibly more. Using eclipsing binaries and double-lined spectroscopic binaries as tracers of dynamically ejected runaways, and high-mass X-ray binaries (HMXBs) as tracers of runaways accelerated by supernova kicks, we find significant contributions from both populations. The data suggest that HMXBs have lower velocity dispersion relative to dynamically ejected binaries, consistent with the former corresponding to less energetic supernova kicks that failed to unbind the components. Evidence suggests that our fast runaways are dominated by dynamical, rather than supernova, ejections. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.06596v2-abstract-full').style.display = 'none'; document.getElementById('1810.06596v2-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, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 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 to ApJ Letters. 10 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Oey et al. 2018, ApJL, 867, L8 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.06673">arXiv:1807.06673</a> <span> [<a href="https://arxiv.org/pdf/1807.06673">pdf</a>, <a href="https://arxiv.org/ps/1807.06673">ps</a>, <a href="https://arxiv.org/format/1807.06673">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/sty2041">10.1093/mnras/sty2041 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Frequency of Dwarf Galaxy Multiples at Low Redshift in SDSS vs. Cosmological Expectations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Patton%2C+D+R">David R. Patton</a>, <a href="/search/astro-ph?searchtype=author&query=Stierwalt%2C+S">Sabrina Stierwalt</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez-Gomez%2C+V">Vicente Rodriguez-Gomez</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N+J">Nitya J. Kallivayalil</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+K">Kelsey Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Pearson%2C+S">Sarah Pearson</a>, <a href="/search/astro-ph?searchtype=author&query=Privon%2C+G">George Privon</a>, <a href="/search/astro-ph?searchtype=author&query=Putman%2C+M+E">Mary E. Putman</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1807.06673v1-abstract-short" style="display: inline;"> We quantify the frequency of companions of low redshift ($0.013 < z < 0.0252$), dwarf galaxies ($2 \times 10^8$ M$_\odot <$ M$_{*} < 5 \times 10^9$ M$_\odot$) that are isolated from more massive galaxies in SDSS and compare against cosmological expectations using mock observations of the Illustris simulation. Dwarf multiples are defined as 2 or more dwarfs that have angular separations > 55'', pro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.06673v1-abstract-full').style.display = 'inline'; document.getElementById('1807.06673v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.06673v1-abstract-full" style="display: none;"> We quantify the frequency of companions of low redshift ($0.013 < z < 0.0252$), dwarf galaxies ($2 \times 10^8$ M$_\odot <$ M$_{*} < 5 \times 10^9$ M$_\odot$) that are isolated from more massive galaxies in SDSS and compare against cosmological expectations using mock observations of the Illustris simulation. Dwarf multiples are defined as 2 or more dwarfs that have angular separations > 55'', projected separations r$_p < 150$ kpc and relative line-of-sight velocities $螖V_{\rm LOS} < 150$ km/s. While the mock catalogs predict a factor of 2 more isolated dwarfs than observed in SDSS, the mean number of observed companions per dwarf is $N_c \sim 0.04$, in good agreement with Illustris when accounting for SDSS sensitivity limits. Removing these limits in the mock catalogs predicts $N_c\sim 0.06$ for future surveys (LSST, DESI), which will be complete to M$_* = 2\times 10^8$ M$_\odot$. The 3D separations of mock dwarf multiples reveal a contamination fraction of $\sim$40% in observations from projection effects. Most isolated multiples are pairs; triples are rare and it is cosmologically improbable that bound groups of dwarfs with more than 3 members exist within the parameter range probed in this study. We find that $<$1% of LMC-analogs in the field have an SMC-analog companion. The fraction of dwarf "Major Pairs'' (stellar mass ratio $>$1:4) steadily increases with decreasing Primary stellar mass, whereas the cosmological "Major Merger rate'' (per Gyr) has the opposite behaviour. We conclude that cosmological simulations can be reliably used to constrain the fraction of dwarf mergers across cosmic time. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.06673v1-abstract-full').style.display = 'none'; document.getElementById('1807.06673v1-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 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 16 Figures, submitted to MNRAS (Referee stage ; Comments are welcome)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.03791">arXiv:1807.03791</a> <span> [<a href="https://arxiv.org/pdf/1807.03791">pdf</a>, <a href="https://arxiv.org/format/1807.03791">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/sty2052">10.1093/mnras/sty2052 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Modeling the Baryon Cycle in Low Mass Galaxy Encounters: the Case of NGC 4490 & NGC 4485 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pearson%2C+S">Sarah Pearson</a>, <a href="/search/astro-ph?searchtype=author&query=Privon%2C+G+C">George C. Privon</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=Putman%2C+M+E">Mary E. Putman</a>, <a href="/search/astro-ph?searchtype=author&query=Mart%C3%ADnez-Delgado%2C+D">David Mart铆nez-Delgado</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+K+V">Kathryn V. Johnston</a>, <a href="/search/astro-ph?searchtype=author&query=Gabany%2C+R+J">R. Jay Gabany</a>, <a href="/search/astro-ph?searchtype=author&query=Patton%2C+D+R">David R. Patton</a>, <a href="/search/astro-ph?searchtype=author&query=Kallivayalil%2C+N">Nitya Kallivayalil</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1807.03791v2-abstract-short" style="display: inline;"> Discoveries of low mass galaxy pairs and groups are increasing. Studies indicate that dwarf galaxy pairs are gas rich in the field and exhibit elevated star formation rates, suggestive of interactions. Lacking are dynamical models of observed dwarf galaxy pairs to disentangle the physical processes regulating their baryon cycles. We present new optical data and the first detailed theoretical model… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.03791v2-abstract-full').style.display = 'inline'; document.getElementById('1807.03791v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.03791v2-abstract-full" style="display: none;"> Discoveries of low mass galaxy pairs and groups are increasing. Studies indicate that dwarf galaxy pairs are gas rich in the field and exhibit elevated star formation rates, suggestive of interactions. Lacking are dynamical models of observed dwarf galaxy pairs to disentangle the physical processes regulating their baryon cycles. We present new optical data and the first detailed theoretical model of an observed tidal encounter between two isolated low mass galaxies, NGC 4490 & NGC 4485. This system is an isolated analog of the Magellanic Clouds and is surrounded by a ~50 kpc extended HI envelope. We use hybrid $N$-body and test-particle simulations along with a visualization interface $Identikit$ to simultaneously reproduce the observed present-day morphology and kinematics. Our results demonstrate how repeated encounters between two dwarf galaxies can "park" baryons at very large distances, without the aid of environmental effects. Our best match to the data is an 8:1 mass ratio encounter where a one-armed spiral is induced in the NGC 4490-analog, which we postulate explains the nature of diffuse starlight presented in the new optical data. We predict that the pair will fully merge in ~370 Myr, but that the extended tidal features will continue to evolve and return to the merged remnant over ~5 Gyr. This pre-processing of baryons will affect the efficiency of gas stripping if such dwarf pairs are accreted by a massive host. In contrast, in isolated environments this study demonstrates how dwarf-dwarf interactions can create a long-lived supply of gas to the merger remnant. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.03791v2-abstract-full').style.display = 'none'; document.getElementById('1807.03791v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">30 pages, 11 figures, 2 tables, minor edits to reflect published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 480, 3, 2018, p: 3069 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1805.04079">arXiv:1805.04079</a> <span> [<a href="https://arxiv.org/pdf/1805.04079">pdf</a>, <a href="https://arxiv.org/format/1805.04079">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab001b">10.3847/1538-4357/ab001b <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First Gaia Dynamics of the Andromeda System: DR2 Proper Motions, Orbits, and Rotation of M31 and M33 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=van+der+Marel%2C+R+P">Roeland P. van der Marel</a>, <a href="/search/astro-ph?searchtype=author&query=Fardal%2C+M+A">Mark A. Fardal</a>, <a href="/search/astro-ph?searchtype=author&query=Sohn%2C+S+T">Sangmo Tony Sohn</a>, <a href="/search/astro-ph?searchtype=author&query=Patel%2C+E">Ekta Patel</a>, <a href="/search/astro-ph?searchtype=author&query=Besla%2C+G">Gurtina Besla</a>, <a href="/search/astro-ph?searchtype=author&query=del+Pino-Molina%2C+A">Andr茅s del Pino-Molina</a>, <a href="/search/astro-ph?searchtype=author&query=Sahlmann%2C+J">Johannes Sahlmann</a>, <a href="/search/astro-ph?searchtype=author&query=Watkins%2C+L+L">Laura L. Watkins</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1805.04079v2-abstract-short" style="display: inline;"> The 3D velocities of M31 and M33 are important for understanding the evolution and cosmological context of the Local Group. Their most massive stars are detected by Gaia, and we use Data Release 2 (DR2) to determine the galaxy proper motions (PMs). We select galaxy members based on, e.g., parallax, PM, color-magnitude-diagram location, and local stellar density. The PM rotation of both galaxies is… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.04079v2-abstract-full').style.display = 'inline'; document.getElementById('1805.04079v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1805.04079v2-abstract-full" style="display: none;"> The 3D velocities of M31 and M33 are important for understanding the evolution and cosmological context of the Local Group. Their most massive stars are detected by Gaia, and we use Data Release 2 (DR2) to determine the galaxy proper motions (PMs). We select galaxy members based on, e.g., parallax, PM, color-magnitude-diagram location, and local stellar density. The PM rotation of both galaxies is confidently detected, consistent with the known line-of-sight rotation curves: $V_{\rm rot} = -206\pm86$ km s$^{-1}$ (counter-clockwise) for M31, and $V_{\rm rot} = 80\pm52$ km s$^{-1}$ (clockwise) for M33. We measure the center-of-mass PM of each galaxy relative to surrounding background quasars in DR2. This yields that $(渭_{伪*},渭_未)$ equals $(65 \pm 18 , -57 \pm 15)$ $渭$as yr$^{-1}$ for M31, and $(31 \pm 19 , -29 \pm 16)$ $渭$as yr$^{-1}$ for M33. In addition to the listed random errors, each component has an additional residual systematic error of 16 $渭$as yr$^{-1}$. These results are consistent at 0.8$蟽$ and 1.0$蟽$ with the (2 and 3 times higher-accuracy) measurements already available from Hubble Space Telescope (HST) optical imaging and VLBA water maser observations, respectively. This lends confidence that all these measurements are robust. The new results imply that the M31 orbit towards the Milky Way is somewhat less radial than previously inferred, $V_{\rm tan, DR2+HST} = 57^{+35}_{-31}$ km s$^{-1}$, and strengthen arguments that M33 may be on its first infall into M31. The results highlight the future potential of Gaia for PM studies beyond the Milky Way satellite system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.04079v2-abstract-full').style.display = 'none'; document.getElementById('1805.04079v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 January, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 May, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">15 pages, 7 figures, ApJ, in press</span> </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" 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