BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Gaia EDR3 proper motions of Milky Way dwarfs DTSTART;VALUE=DATE-TIME:20230320T103000Z DTEND;VALUE=DATE-TIME:20230320T104500Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-200@meetings.aip.de DESCRIPTION:Speakers: Hefan Li (National Astronomical Observatories)\nBase d on Gaia Early Data Release 3 (EDR3)\, we estimate the proper motions for 46 dwarf galaxies of the Milky Way. The uncertainties in proper motions\, determined by combining both statistical and systematic errors\, are smal ler by a factor 2.5\, when compared with Gaia Data Release 2. We have deri ved orbits in four Milky Way potential models that are consistent with the MW rotation curve. Although the type of orbit (ellipse or hyperbola) are very dependent on the potential model\, the pericenter values are firmly determined\, largely independent of the adopted MW mass model. By analyzin g the orbital phases\, we found that the dwarf galaxies are highly concent rated close to their pericenter\, rather than to their apocenter as expect ed from Kepler's law. This may challenge the fact that most dwarf galaxies are Milky Way satellites\, or alternatively indicates an unexpected large number of undiscovered dwarf galaxies lying very close to their apocenter s. Between half and two thirds of the satellites have orbital poles that i ndicate them to orbit along the Vast Polar Structure (VPOS)\, with the vas t majority of these co-orbiting in a common direction also shared by the M agellanic Clouds\, which is indicative of a real structure of dwarf galax ies.\n\nhttps://iaus379.aip.de/event/20/contributions/200/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/200/ END:VEVENT BEGIN:VEVENT SUMMARY:Wide binaries in dwarf galaxies as probes of dark matter DTSTART;VALUE=DATE-TIME:20230320T140000Z DTEND;VALUE=DATE-TIME:20230320T142500Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-175@meetings.aip.de DESCRIPTION:Speakers: Christopher Kervick (Carnegie Mellon University)\nVe ry wide stellar binaries\, with semi-major axes of hundreds of AU and larg er\, constitute sensitive probes of the underlying gravitational potential in which they live\, having provided some of the first experimental const raints on the nature of dark matter in the Milky Way halo.  As such\, the detection and characterization of populations of wide binaries in nearby old dwarf galaxies could provide us with a completely new window onto the properties of dark matter on the smallest scales. We have designed a new method\, geometric in its essence\, for deriving the density and projected semimajor-axis distribution of a population of binary systems that does n ot resort to standard estimators of the two-point correlation function\, a nd will present results of applying it to our Hubble Space Telescope surve y of the Ursa Minor dwarf spheroidal galaxy.  We will discuss the competi ng effects of the survey's depth\, coverage\, and angular resolution limit s against those of foreground stars and background galaxies\, and highligh t the potential advantages that JWST and the Roman Space Telescope may off er to this specific problem.\n\nhttps://iaus379.aip.de/event/20/contributi ons/175/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/175/ END:VEVENT BEGIN:VEVENT SUMMARY:Mapping the deforming dark matter haloes of the Milky Way and the LMC with stellar streams DTSTART;VALUE=DATE-TIME:20230320T104500Z DTEND;VALUE=DATE-TIME:20230320T110000Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-210@meetings.aip.de DESCRIPTION:Speakers: Sophia Lilleengen (University of Surrey)\nThe ongoin g merger of the Milky Way and the Large Magellanic Cloud (LMC) is deformin g the dark matter haloes of both galaxies\, effectively making these galax ies a local dark matter collider. Within this collider\, stellar streams a ct as useful detectors as they are very sensitive to the gravitational pot ential\, and span large parts of the Milky Way halo. \nThe Orphan-Chenab ( OC) stream is particularly insightful as it spans the inner and outer Milk y Way\, and it passes close to the LMC (within 10kpc). In this talk\, I wi ll present the first models of the OC stream in the time-dependent halos o f the Milky Way and the LMC that are described by basis function expansion s of N-body simulations of the Milky Way-LMC passage. I will show how thes e deformations have an observable signature on the OC stream. In particula r\, we find that the Milky Way’s dipole has the most significant effect. \nWe do not currently have the tools to fit these deformations and ignori ng them may result in biases. To test this\, we fit mock streams evolved i n these deforming potentials with current state-of-the-art stream models. Even though the MW is spherical in these mocks\, we infer extremely large flattenings of the DM halos with q=0.6 and q=1.5. This shows that current measurements of the MW DM halo shape are likely biased and motivates the n eed for computationally efficient tools to describe these deformations. Th is work is an important first step in measuring the Milky Way’s mass pro file over time.\n\nhttps://iaus379.aip.de/event/20/contributions/210/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/210/ END:VEVENT BEGIN:VEVENT SUMMARY:Equilibrium dynamical models for the Large Magellanic Cloud DTSTART;VALUE=DATE-TIME:20230320T110000Z DTEND;VALUE=DATE-TIME:20230320T111500Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-207@meetings.aip.de DESCRIPTION:Speakers: Nikolay Kacharov (AIP)\nThe Large Magellanic Cloud ( LMC) has a complex dynamics driven by both internal and external processes . The external forces are due to tidal interactions with the Small Magella nic Cloud (SMC) and the Milky Way\, while internally its dynamics mainly d epends on the stellar\, gas\, and dark matter mass distributions. Despite the overall complexity of the system\, very often simple physical models c an give us important insights about the main driving factors. Here we focu s on the internal forces and attempt to model the proper motions (PM) of ~ 1 000 000 stars in the LMC as measured by Gaia with an axisymmetric dynami cal model\, based on the Jeans equations. We test both cored and cusped sp herical Navarro-Frenk-White (NFW) dark matter halos to fit the LMC gravita tional potential. We find that this simple model is very successful at sel ecting a clean sample of genuine LMC member stars and correctly predicts t he geometry and orientation of the LMC with respect to the observer withou t additional prior information. Our Jeans dynamical models describes well the mean velocity and velocity dispersion of the LMC stellar disc\, howeve r it fails to describe the motions of the LMC bar\, which is a non-axisymm etric feature dominating the central region. We plan a triaxial Schwarzsch ild approach as a next step for the dynamical modelling of the LMC.\n\nhtt ps://iaus379.aip.de/event/20/contributions/207/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/207/ END:VEVENT BEGIN:VEVENT SUMMARY:The masses of Local Group galaxies and the baryonic Tully-Fisher r elation DTSTART;VALUE=DATE-TIME:20230320T113000Z DTEND;VALUE=DATE-TIME:20230320T114500Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-222@meetings.aip.de DESCRIPTION:Speakers: Stacy McGaugh (Case Western Reserve University)\nThe baryonic Tully-Fisher relation is a correlation between the quantity of s tars and gas in a galaxy and its flat rotation speed. The relation found i n external galaxies appears to hold for rotationally supported Local Group galaxies. It may also hold for some if not all of the pressure supported dwarfs. The flat rotation speed depends on dynamical mass\, providing a co nstraint on total mass that is independent of other considerations.\n\nhtt ps://iaus379.aip.de/event/20/contributions/222/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/222/ END:VEVENT BEGIN:VEVENT SUMMARY:(Machine)-learning the galactic potential DTSTART;VALUE=DATE-TIME:20230320T094300Z DTEND;VALUE=DATE-TIME:20230320T094500Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-296@meetings.aip.de DESCRIPTION:Speakers: Wassim Tenachi (Observatoire de Strasbourg)\nRecent observational efforts such as Gaia are leading us toward a new era of data abundance which offers us an incredible opportunity for discovering new p hysics. Thanks to recent advances in the field of machine learning\, it is possible to extract valuable information from the colossal amount of data now available.\nIn particular\, auto-differentiation allows us to get a b etter grasp of galactic dynamics. It might even enable us to capture a pre cise and agnostic map of the gravitational potential of the Milky-Way and the underlying dark matter distribution from a mere snapshot of stellar po sitions and velocities.\nHowever\, machine learning in the context of phys ics is both plagued and blessed by one of its most potent components: neur al networks\, which are extremely powerful and flexible for modelling phys ical systems but largely consist in non-interpretable black boxes. Thus\, a complementary approach based on symbolic regression is currently being b uilt in the goal of recovering the analytical expression describing a pote ntial. We will present a preliminary study of these new approaches.\n\nhtt ps://iaus379.aip.de/event/20/contributions/296/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/296/ END:VEVENT BEGIN:VEVENT SUMMARY:Precise distances from Gaia astrometry and large-scale spectroscop ic surveys with StarHorse DTSTART;VALUE=DATE-TIME:20230320T115300Z DTEND;VALUE=DATE-TIME:20230320T115500Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-295@meetings.aip.de DESCRIPTION:Speakers: Anna Queiroz (AIP)\nThe ESA's astrometric mission Ga ia has added an invaluable wealth of astrometric and photometric data for more than a billion stars in our Galaxy (Gaia Collaboration et al. 2018). The synergy between Gaia's third data release\, EDR3\, and large scale-spe ctroscopic surveys give us comprehensive information about individual star s in the Milky Way. To complement these data sets\, we deliver new catalog ues (10 million stars) of distance\, extinction\, masses\, and additional parameters produced with the Bayesian isochrone-fitting code StarHorse (Qu eiroz et al. 2018). These results are crucial for the study of Milky Way d ynamics and the characterization of disrupted dwarf galaxies\; we show app lications of our produced data to the study of Sagittarius and Gaia Encela dus. The resulting catalogues are essential to model the Milky Way's chemo -dynamical history and further understand the formation of disk galaxies.\ n\nhttps://iaus379.aip.de/event/20/contributions/295/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/295/ END:VEVENT BEGIN:VEVENT SUMMARY:The Halo Outskirts With Variable Stars (HOWVAST) survey: detecting Milky Way mass tracers beyond 100 kpc DTSTART;VALUE=DATE-TIME:20230320T115100Z DTEND;VALUE=DATE-TIME:20230320T115300Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-294@meetings.aip.de DESCRIPTION:Speakers: Ricardo R. Munoz (Universidad de Chile)\nAccording to our currently favored cosmological framework\, the Lambda- Cold Dark Ma tter model\, galaxies like the Milky Way were built through the accretion and merger of smaller systems. In this scenario\, the extended halo of the Milky Way must retain information about this process. Key to unveiling t his information is our ability to trace the outermost regions of the halo by detecting and studying the properties of bound objects. One of the most relevant family of such objects is the low-mass\, old-population\, RR Lyr ae (RRL) pulsational variables\, ubiquitous in the halo and for which prec ise distances can be obtained. RRLs have proven to be essential in related but different areas: in this particular\, we seek to detect distant (>100 kpc) RRLs that can help improve estimations of the Milky Way mass\, espec ially at large distances. In this context\, we report our search for faint RR Lyrae stars using Dark Energy Camera (DECam) data over ~400 sq. deg.\, as part of the Halo Outskirts With Variable Stars (HOWVAST) survey\, wher e we detect more than ∼500 RR Lyrae candidates ranging in heliocentric d istances from 7 to 270 kpc. 27 of these stars are located beyond 100 kpc f rom the Galactic center\, increasing our current sample of distant mass tr acers\, critical to improve current Milky Way mass determinations which su ffer from at least 50% uncertainty. HOWVAST represents our effort to carry out frontier Galactic science done with RRLs\, and should only be surpass ed once the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSS T) begins scientific operations\, which is expected for mid 2024.\n\nhttps ://iaus379.aip.de/event/20/contributions/294/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/294/ END:VEVENT BEGIN:VEVENT SUMMARY:The survey of planetary nebulae in Andromeda (M31). Chemical enric hment of the thin and thicker discs of Andromeda: Oxygen to argon abundanc e ratios for planetary nebulae and HII regions DTSTART;VALUE=DATE-TIME:20230320T094100Z DTEND;VALUE=DATE-TIME:20230320T094300Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-241@meetings.aip.de DESCRIPTION:Speakers: Magda Arnaboldi (ESO)\nWe use oxygen and argon abund ances for planetary nebulae (PNe) with low internal extinction (progenitor ages of (>4.5 Gyr) and high extinction (progenitor ages \n\nhttps://iaus3 79.aip.de/event/20/contributions/241/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/241/ END:VEVENT BEGIN:VEVENT SUMMARY:Bayesian action-based dynamical model for M31 DTSTART;VALUE=DATE-TIME:20230320T093900Z DTEND;VALUE=DATE-TIME:20230320T094100Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-240@meetings.aip.de DESCRIPTION:Speakers: Paula Gherghinescu (University of Surrey)\nThe posit ion\, velocity\, and chemical composition of each star provide clues to th e evolutionary history of galaxies. While the Gaia mission has offered inv aluable information about the Milky Way\, to understand the growth of disk galaxies in the Universe we must look beyond our galaxy.\n\nThe Andromeda Galaxy (M31) is ideal for this task thanks to its proximity (making it po ssible for individual stars to be resolved) and its inclination angle\, pr oviding a gateway to external galaxies study. Furthermore\, our position o utside of this galaxy is ideal for an unbiased view of its dark matter hal o.\n\nI am presenting a novel Bayesian action-based dynamical tool that ex ploits stars harvested in M31. This pipeline aims to recover parameters of the galaxy describing its distribution function and dark matter density p rofile. This will be used to understand the galaxy’s accretion history a nd accumulation of dark matter.\n\nAs a first test\, the pipeline has been applied to the Auriga simulations of M31-like galaxies. The new Bayesian action-based model recovers well the parameters of the potential and of th e distribution function of the halos even when fitted with non-phase mixed \, accreted stellar data. Furthermore\, this allowed testing the equilibri um assumptions of galaxies and the generality with which double-power law distribution functions can be used to fit stellar halo components of galax ies.\n\nhttps://iaus379.aip.de/event/20/contributions/240/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/240/ END:VEVENT BEGIN:VEVENT SUMMARY:Characterizing the distant spur feature of the Sagittarius stream DTSTART;VALUE=DATE-TIME:20230320T093700Z DTEND;VALUE=DATE-TIME:20230320T093900Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-238@meetings.aip.de DESCRIPTION:Speakers: Manuel Bayer (Kapteyn Astronomical Institute\, Unive rsity of Groningen\, the Netherlands)\nProviding a detailed picture of the complexity of the Sagittarius stream is an important aspect of investigat ing the outer Galactic halo and constraining the Milky Way potential. Seve ral attempts have been made to model the complex structure of the Sagittar ius stream. However\, no model has yet been able to match all the intricat e features observed for the stream\, including for instance a bifurcation and several wraps. Most recently\, it was discovered that the stream also has a very distant spur feature at least out to ~120 kpc (Sesar et al.\, 2 017). \n\nThe aim of this work is to characterize this Sagittarius stream spur using blue horizontal branch stars\, one of the few standard candle t racers reaching these outer realms of the Milky Way. Blue horizontal branc h candidates were selected using a unique combination of narrow- and broad -band photometry as well as Gaia astrometry. Follow-up optical spectra are obtained using ESO/FORS2. The sample allows us to trace the structure to even larger distances. The observed radial velocities of these stars discr iminate different model predictions for the origin of this mysterious spur feature.\n\nhttps://iaus379.aip.de/event/20/contributions/238/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/238/ END:VEVENT BEGIN:VEVENT SUMMARY:On the Fast (Stream) Track: Rapid construction of stellar stream p aths DTSTART;VALUE=DATE-TIME:20230320T093500Z DTEND;VALUE=DATE-TIME:20230320T093700Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-229@meetings.aip.de DESCRIPTION:Speakers: Nathaniel Starkman (University of Toronto)\nStellar streams are sensitive probes of the Galactic potential. The likelihood of a model given stream data can only be assessed using simulations. However\ , comparison to simulation is challenging in a noisy 6D phase space in whi ch even the stream paths are hard to quantify. Here we present a novel app lication of Self-Organizing Maps and first-order Kalman Filters to reconst ruct the stream path\, propagating measurement errors and data sparsity in to the stream path uncertainty. The technique is Galactic- model independe nt\, non-parametric\, and works on phase-wrapped streams. We can uniformly analyze and compare data with simulation.\n\nhttps://iaus379.aip.de/event /20/contributions/229/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/229/ END:VEVENT BEGIN:VEVENT SUMMARY:Chemo-dynamical modelling of galaxies with DYNAMITE DTSTART;VALUE=DATE-TIME:20230320T133000Z DTEND;VALUE=DATE-TIME:20230320T134500Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-186@meetings.aip.de DESCRIPTION:Speakers: Alice Zocchi (University of Vienna)\nThe combination of astrometric and chemical information from Galactic stars has revealed great detail about the structure\, dynamics and history of our own Galaxy. In external galaxies\, it is impossible to map the distribution of indivi dual stars\, but high signal-to-noise integral field spectroscopy data at various wavelengths\, together with sophisticated dynamical models\, give us the opportunity to gather information on the structure\, dynamics and h istory of these systems.\nI will present the Schwarzschild code DYNAMITE ( https://dynamics.univie.ac.at/dynamite_docs/index.html)\, which models gal actic dynamics by means of a superposition of stellar orbits. DYNAMITE is equipped to deal with very detailed kinematic measurements\, allowing us t o better exploit high-quality IFU datasets of nearby galaxies. I will prov ide a detailed overview of the challenges of such a modelling technique an d introduce first applications on observations and simulations. I will als o show how DYNAMITE makes it possible to identify families of orbits origi nating from different dynamical structures within a galaxy\, which in some cases challenge the current picture of galaxies obtained from pure stella r light decompositions. Finally\, I will anticipate our future plans for D YNAMITE\, adding additional tracers (globular clusters\, extended gas)\, a nd dealing with discrete data.\n\nhttps://iaus379.aip.de/event/20/contribu tions/186/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/186/ END:VEVENT BEGIN:VEVENT SUMMARY:How 4MOST and MOONS will improve constraints on the dynamical mass es of Local Group galaxies DTSTART;VALUE=DATE-TIME:20230320T134500Z DTEND;VALUE=DATE-TIME:20230320T140000Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-184@meetings.aip.de DESCRIPTION:Speakers: Steffen Mieske ()\nThe wide-field spectrographs 4MOS T and MOONS will enter operations in 2024 at the ESO Paranal Observatory. These upcoming survey facilities will play an important role in various fi elds over the next decade. In particular\, both will host surveys aimed at observing nearby Local Group galaxies. Here\, we provide an overview of a ll the planned 4MOST and MOONS surveys that focus on Local Group galaxy ki nematics. We will describe how their scientific performances complement Ga ia and other spectroscopic surveys in the field of nearby galaxy kinematic s. In addition\, we will outline the outstanding scientific questions rega rding the local group galaxy masses and dynamics\, in which the MOONS and 4MOST survey science will allow major progress. Finally\, we will describe how the community can access observing time and data\, to participate in solving fundamental issues in this field.\n\nhttps://iaus379.aip.de/event/ 20/contributions/184/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/184/ END:VEVENT BEGIN:VEVENT SUMMARY:Discrete Schwarzschild models of dwarf spheroidal galaxies: New te sts of the dark matter distribution. DTSTART;VALUE=DATE-TIME:20230320T114900Z DTEND;VALUE=DATE-TIME:20230320T115100Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-237@meetings.aip.de DESCRIPTION:Speakers: Erik Aquino Ortíz (Instituto de Astrofísica\, Pont ificia Universidad Católica de Chile)\nAn accurate and unambiguous determ ination of the inner distribution of dark matter in dwarf spheroidal (dSph ) galaxies has proven to be a challenge for a few decades now. Some of the complications include the degeneracies inherent to the dynamics of stella r systems\, but also the limits of the available data (e.g.\, just one com ponent of the 3D space velocities of the tracers)\, and the need for simpl ifying assumptions of the analysis methods typically employed. In this con tribution\, we will present initial results from applying our fully discre te axisymmetric Schwarzschild code to this problem. We first study mock da tasets for dSph galaxies from the Gaia Challenge\, which help us identify the pros and cons on the tool we use\, and understand the limits imposed b y the degeneracies inherent to the problem. We explore datasets of various sizes\, and all combination of available velocity components\, i.e.\, onl y line-of-sight velocities\, only proper motions\, and both. Our methodolo gy also avoids restrictive assumptions about the degree of orbital (an)iso tropy. We then apply the tool to line-of-sight velocity data for the Sculp tor and Fornax dwarfs\, and compare our preliminary results to published w ork.\n\nhttps://iaus379.aip.de/event/20/contributions/237/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/237/ END:VEVENT BEGIN:VEVENT SUMMARY:Constraints on dark matter distribution in dwarf spheroidal galaxi es based on the 4th-order Jeans analysis DTSTART;VALUE=DATE-TIME:20230320T114700Z DTEND;VALUE=DATE-TIME:20230320T114900Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-230@meetings.aip.de DESCRIPTION:Speakers: M. Dafa Wardana (Astronomical Institute\, Tohoku Uni versity)\nThe mass-anisotropy degeneracy is still one of the main issues i n estimating the dark matter distribution in dwarf spheroidal galaxies\, e specially for the commonly used second-order Jeans analysis. We study the extension of spherical Jeans modeling by incorporating the fourth-order ve locity moments under the assumption of dynamical equilibrium and a constan t velocity anisotropy. The inclusion of fourth-order velocity moments allo ws stars’ l.o.s velocity distribution\, which is sensitive to the value of the velocity anisotropy parameter\, to be flexible\, covering thin-tail ed to heavy-tailed distributions that is inaccessible if only second-order moments are used. We test our stellar dynamical modeling using mock data that resembles Draco dSph with either central NFW cusp or Burkert core and isotropic velocity anisotropy. Using 500 sample stars\, our simulations s how that incorporating fourth-order velocity moments improves the results compared to when only second-order moments are used. Typically\, the veloc ity anisotropy is constrained two times better\, while it is ~50% improvem ent for the constraint of the inner dark matter density slope with both pa rameters being recovered within 1σ uncertainties.\n\nhttps://iaus379.aip. de/event/20/contributions/230/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/230/ END:VEVENT BEGIN:VEVENT SUMMARY:Internal proper motions of dwarf spheroidal galaxies: Constraining the density and properties of dark matter DTSTART;VALUE=DATE-TIME:20230320T114500Z DTEND;VALUE=DATE-TIME:20230320T114700Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-228@meetings.aip.de DESCRIPTION:Speakers: Eduardo Vitral (Space Telescope Science Institute)\n Determination of the mass density profiles of dwarf galaxies (and specific ally whether there is a central core or cusp) provides a critical test of both the properties of dark matter (DM) and the physics of cosmological st ructure formation. The nearby classical dwarf spheroidal galaxies (dSphs) of the Milky Way yield some of the best dynamical constraints. While large line-of-sight velocity datasets exist (some thousand stars per galaxy)\, interpretation is hindered by the well-known mass vs. velocity-anisotropy degeneracy of stellar dynamics. This can be resolved with proper motion (P M) measurements that yield 3-D velocity information\, which is beyond the reach of Gaia\, given the small velocity dispersions of dSphs and the abse nce of bright stars. To attain the necessary precision and a proper handli ng of systematics for this kind of study\, one then needs not only longer baselines\, but the combination of many fields from different state-of-the -art telescopes. We thus obtain separate PMs from the nearby Draco and Scu lptor dSphs from 3 epochs of HST data for 5 fields\, from 2 epochs of new JWST observations of these same fields as well as two additional fields\, all of which are further compared to Gaia DR3 positions. From this long-te rm program we will be able to provide a direct determination of their velo city anisotropy profiles\, and combined with dynamical models\, tightly co nstrain the slopes of their DM density profiles. No comparable measurement s exist to date\, and the precision attainted will be fundamental to lay m ore robust constraints on both the nature of DM\, and the physical mechani sms that shape DM density profiles in galaxies. We will discuss the progre ss of our program\, and some initial results from the observational epochs and data obtained to date. Additional observations to be obtained through 2025 will yield the final accuracies needed for our goals.\n\nhttps://iau s379.aip.de/event/20/contributions/228/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/228/ END:VEVENT BEGIN:VEVENT SUMMARY:Proper Motions\, Orbits\, and Tidal Influences of Milky Way Dwarf Spheroidal Galaxies DTSTART;VALUE=DATE-TIME:20230320T111500Z DTEND;VALUE=DATE-TIME:20230320T113000Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-185@meetings.aip.de DESCRIPTION:Speakers: Andrew Pace (Carnegie Mellon University)\nWe combine Gaia EDR3 astrometry with accurate photometry and utilize a probabilistic mixture model to measure the systemic proper motion of 52 dwarf spheroida l (dSph) satellite galaxies of the Milky Way (MW). For the 46 dSphs with l iterature line-of-sight velocities we compute orbits in both a MW and a co mbined MW + Large Magellanic Cloud (LMC) potential and identify Car II\, C ar III\, Hor I\, Hyi I\, Phx II\, and Ret II as likely LMC satellites. 40% of our dSph sample has a >25% change in pericenter and/or apocenter with the MW + LMC potential. For these orbits\, we Monte Carlo sample over the observational uncertainties for each dSph and the uncertainties in the MW and LMC potentials. We predict that Ant II\, Boo III\, Cra II\, Gru II\, a nd Tuc III should be be tidally disrupting by comparing each dSph's averag e density relative to the MW density at its pericenter. dSphs with large e llipticity (CVn I\, Her\, Tuc V\, UMa I\, UMa II\, UMi\, Wil 1) show a pre ference for their orbital direction to align with their major axis even fo r dSphs with large pericenters. We compare the dSph radial orbital phase t o subhalos in MW-like N-body simulations and infer that there is not an ex cess of satellites near their pericenter. With projections of future Gaia data releases\, we find dSph orbital precision will be limited by uncertai nties in the distance and/or MW potential rather than proper motion precis ion. Finally\, we provide our membership catalogs to enable community foll ow-up.\n\nhttps://iaus379.aip.de/event/20/contributions/185/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/185/ END:VEVENT BEGIN:VEVENT SUMMARY:Detection of density variations and off-track features in stellar streams DTSTART;VALUE=DATE-TIME:20230320T092000Z DTEND;VALUE=DATE-TIME:20230320T093500Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-183@meetings.aip.de DESCRIPTION:Speakers: Akshara Viswanathan (Kapteyn Astronomical Institute\ , University of Groningen)\nLike any other galaxy in the universe\, eviden ce shows that the assembly of the Milky Way is irrefutably hierarchical. T he Galactic halo in particular has a nonlinear structure with a vast numbe r of cold stellar streams with complex morphologies that prove to be a pow erful test for the nature and distribution of dark matter in the halo.\n\n In this work\, we select halo main sequence stars using Gaia DR3 proper mo tion and photometry information\, the combination of which renders the red uced proper motion parameter. This parameter allows us to pick out high ta ngential velocity stars in halo orbits independent of the line-of-sight in formation. Our final catalogue consists of about 47 million halo main-sequ ence stars for which we can then determine precise photometric distances w ith typical uncertainties down to 7%. Our sample reaches out until ~20 kpc thereby probing much further out than would be possible using reliable Ga ia parallaxes.\n\nBinned velocity moments on the star map in the latitude\ , longitude and pseudo-azimuth directions pop up several known tidal strea ms in the local halo - particularly retrograde structures\, due to the kin ematic selection. The use of main-sequence stars\, rather than brighter gi ants\, allows us to trace low surface brightness counterparts\, pushing th e substructure searches to Gaia’s magnitude limits.\n\nHere I will prese nt the substructures found and characterise them in more detail\, due to t he added information in derived distances and existing metallicities as we ll as the higher sensitivity in low surface brightness features. For these streams\, we resolve the gaps\, wiggles\, and density breaks reported in the literature more clearly. The faint signs of disequilibrium in the form of kinks and density variations in these thin streams will paint a more d etailed picture of the existence and properties of the dark matter sub-hal oes that perturb them and in turn\, the mass distribution of our Galaxy.\n \nhttps://iaus379.aip.de/event/20/contributions/183/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/183/ END:VEVENT BEGIN:VEVENT SUMMARY:The Power of Milky Way's Stellar Streams with Full 6D+ Phase Space Data Set from S5 and DESI DTSTART;VALUE=DATE-TIME:20230320T085500Z DTEND;VALUE=DATE-TIME:20230320T092000Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-170@meetings.aip.de DESCRIPTION:Speakers: Ting Li ()\nStellar streams are one of the most powe rful tracers to determine the mass of the Milky Way and other nearby galax ies. Full 6D phase space data is necessary for us to get there. In this ta lk\, I will discuss two ongoing spectroscopic programs to study the stella r streams in our Milky Way and highlight a few latest scientific results f rom these two programs. The Southern Stellar Stream Spectroscopic Survey ( S5)\, started in 2018\, is the first systematic program pursuing a complet e census of known streams in the Southern Hemisphere using the fiber-fed A AOmega spectrograph on the Anglo-Australian Telescope. The science results from S5 include a homogeneous study of the kinematic and chemical propert ies of dozen streams in our Milky Way\, the finding of a stream at ~30 kpc possibly perturbed by the dark matter subhalo\, the constraints on the ma ss of the Milky Way and the Large Magellanic Cloud with stellar streams\, and the discovery of the fastest hyper velocity stars ejected from Galacti c center that can be used to study the shape of the Milky Way halo. The Mi lky Way Survey of the Dark Energy Spectroscopic Instrument (DESI)\, on the other hand\, is a recently started 5-yr spectroscopic program in the Nort hern Hemisphere. DESI deploys 5000 fibers over a 3.2 deg diameter field of view at the prime focus of the Mayall 4-meter telescope at the Kitt Peak National Observatory\, with a spectral resolution of R~2500-5000 and a wav elength coverage of 3600-9824 Angstrom. With just the first year of data c ollected in 2021-2022\, 3.6 million unique stars have been observed\, incl uding many stars in the streams of the northern sky (e.g. GD-1) and showin g some interesting features. We are entering an extremely data-rich era in the next decade\, with full 6D+chemistry information on dozens of stellar streams\, to shape our understanding on the chemo-dynamical evolution of the Milky Way\, as well as the nature of the dark matter.\n\nhttps://iaus3 79.aip.de/event/20/contributions/170/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/170/ END:VEVENT BEGIN:VEVENT SUMMARY:The internal kinematics and dynamical masses of Local Group dwarf galaxies DTSTART;VALUE=DATE-TIME:20230320T081500Z DTEND;VALUE=DATE-TIME:20230320T085500Z DTSTAMP;VALUE=DATE-TIME:20241114T092401Z UID:indico-contribution-53-169@meetings.aip.de DESCRIPTION:Speakers: Giuseppina Battaglia (Instituto de Astrofisica de Ca narias)\nWhen interpreted within the framework of Newtonian dynamics\, the internal kinematic properties of Local Group dwarf galaxies indicate that most of these systems are completely dominated by their dark matter halos . These dwarf galaxies are therefore among the best test-benches for dark matter theories. In this review talk\, I will first provide an overview o f our current understanding of the internal kinematic properties of Local Group dwarf galaxies\, and then discuss the current status of determinatio ns of their dark matter content and distribution\, highlighting similariti es and differences in the findings from the various methodologies used in the literature. I will also touch upon the 3D motions of Milky Way satelli te galaxies\nand what they imply for their orbital paths around their host \, discussing possible sources of uncertainty at different\nlevels (e.g. s ystematics in the proper motion determinations\, knowlegde of the gravitat ional potential of the host).\n\nhttps://iaus379.aip.de/event/20/contribut ions/169/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/169/ END:VEVENT END:VCALENDAR