BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Modeling Dark Matter Halo Spin using Observations and Simulations: application to UGC 5288 DTSTART;VALUE=DATE-TIME:20230322T150300Z DTEND;VALUE=DATE-TIME:20230322T150500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-278@meetings.aip.de DESCRIPTION:Speakers: Ansar Sioree (Indian Institute of Astrophysics\, Ben galuru)\nDark matter halo properties are well studied in cosmological simu lations but are very challenging to estimate from observations. The dark m atter halo density profile of galaxies from observations has been modeled previously using multiple probes that trace the dark matter potential\, ho wever\, the angular momentum distribution of the dark matter halos is stil l a subject of debate. In this study\, we demonstrate a method for estimat ing the halo spin and halo concentration of a low luminosity\, gas-rich dw arf galaxy by forward modeling disk properties derived from observations o f the stellar and gas surface densities\, the disk scale length\, the neut ral hydrogen rotation curve\, the bar length\, and bar ellipticity. Our me thod is a combination of semi-analytical techniques and N-body/SPH simulat ions. Here\, we apply our method to the low surface brightness (LSB) dwarf galaxy UGC 5288\, and model its dark matter halo with both a cuspy Hernqu ist profile and a flat-core pseudo-isothermal profile. We find that the be st match with observations is a pseudo-isothermal halo model with core rad ius r$_{c}$ = 0.23 kpc and a high halo spin $\\lambda$ = 0.08 at the viria l radius. These findings are consistent with previous rotation curve estim ates of the halo density profile of UGC 5288\, as well as the theoreticall y predicted high spins of dwarf LSB galaxies. We finally compare our resul ts with the halo spin distribution of barred galaxies in one of the high r esolution cosmological magneto-hydrodynamical simulations TNG-50. We find that our model predicts halo spin distribution of UGC5288 up to a ballpark value\, although\, there remain significant uncertainties due to the form ation history of the dark matter halos from the TNG50 simulations. We also find that the inner halo spin in barred galaxies is different from that o f unbarred ones\, and the halo spin shows weak correlations with bar prope rties.\n\nhttps://iaus379.aip.de/event/20/contributions/278/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/278/ END:VEVENT BEGIN:VEVENT SUMMARY:Census of Northern Local Group Dwarf Galaxies using UNIONS DTSTART;VALUE=DATE-TIME:20230322T093700Z DTEND;VALUE=DATE-TIME:20230322T093900Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-261@meetings.aip.de DESCRIPTION:Speakers: Simon Smith (University of Victoria)\nDwarf galaxies play a key role in probing the dynamics of the Milky Way\, the history of star formation in the Local Group\, and the accretion and retention of ga s in dark matter halos at the smallest scales of galaxy formation. In this work\, we use the Ultraviolet Near-Infrared Optical Northern Survey (UNIO NS)\, the deepest\, widest photometric survey ever carried out in the nort hern hemisphere\, to complete a systematic analysis of 3600 sq. deg. of sk y in search of new dwarf galaxies within 1 Mpc of the Milky Way. This sear ch aims to detect Milky Way satellites\, M31 satellites\, and nearby\, iso lated dwarf galaxies using a matched-filter algorithm. To date\, all previ ously known dwarf galaxies in the survey footprint have been recovered\, e ach with high statistical significance. We present the discovery of a new Milky Way dwarf galaxy candidate\, a new\, faint star cluster\, and report on the follow-up of numerous high confidence candidate detections. The en d goal of this work will be to assess the completeness of the Milky Way sa tellite population as a function of position\, luminosity\, mass\, and siz e. UNIONS imaging\, when completed\, is the approximate depth of the LSST after a year of operation\, and our studies of the northern hemisphere pro vide a complementary approach and foretaste of what will come in the era o f Rubin.\n\nhttps://iaus379.aip.de/event/20/contributions/261/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/261/ END:VEVENT BEGIN:VEVENT SUMMARY:Tidally perturbed 'feeble giant' dwarf galaxies DTSTART;VALUE=DATE-TIME:20230322T093500Z DTEND;VALUE=DATE-TIME:20230322T093700Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-254@meetings.aip.de DESCRIPTION:Speakers: Alexandra Borukhovetskaya (University of Victoria)\n The unusually low velocity dispersion and large sizes of `feeble giant' ga laxies\, such as Crater II or Antlia II\, pose a challenge to our understa nding of dwarf galaxies in the Lambda Cold Dark Matter (LCDM) cosmogony. T heir low velocity dispersions suggest either a dark halo mass much lower t han the minimum expected from hydrogen cooling limit arguments\, or one th at is in the late stages of extreme tidal stripping. The tidal interpretat ion has been favoured in recent work and is supported by the small pericen tric distances consistent with available kinematic estimates from Gaia. We use N-body simulations to examine this interpretation in detail\, assumin g a Navarro-Frenk-White (NFW) profile for the Crater II and Antlia II prog enitor halos. Our main finding is that\, although the low velocity dispers ions can indeed result from the effect of tides\, the large sizes of feebl e giants are inconsistent with this hypothesis. This is because galaxies s tripped in mass to match the observed velocity dispersions are also reduce d to sizes much smaller than the observed half-light radii of Crater II an d Antlia II. Unless their sizes has been substantially overestimated\, rec onciling systems like these (including Andromeda XXV and XIX) with LCDM re quires that either (i) they are not bound and near equilibrium (unlikely\, given their crossing times are shorter than the time elapsed since perice ntre)\, or that (ii) their progenitor halos deviate from the assumed NFW p rofile. The latter alternative may signal that baryons can affect the inne r halo cusp even in extremely faint dwarfs or\, more intriguingly\, may si gnal effects associated with the intimate nature of the dark matter\, such as finite self-interactions\, or other such deviations from the canonical LCDM paradigm.\n\nhttps://iaus379.aip.de/event/20/contributions/254/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/254/ END:VEVENT BEGIN:VEVENT SUMMARY:Dwarf early-type galaxies in the Coma and Virgo clusters: dynamica l masses\, kinematically-decoupled cores\, stellar populations DTSTART;VALUE=DATE-TIME:20230323T143000Z DTEND;VALUE=DATE-TIME:20230323T143200Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-280@meetings.aip.de DESCRIPTION:Speakers: Kirill Grishin (Astroparticule et Cosmologie)\nGalax y clusters are the largest gravitationally bound structures in the Univers e. Numerical simulations provide detailed scenarios on how they assemble a nd evolve over the lifetime of the Universe\, but observational evidences supporting these predictions are still elusive. Galaxy populations in near by clusters are dominated by dwarf stellar systems\, and the number of the se galaxies continues to grow over time even at the present epoch.\nOver t he last 4 years\, using MMT Binospec we collected a rich spectroscopic dat aset\, which comprises over 250 dwarf early-type galaxies in three massive nearby clusters: Coma (D=99 Mpc)\, Abell 2147 (D=165 Mpc)\, and Abell 168 (D=193 Mpc). We have also reduced and analyzed spectra of dwarf galaxies in the Virgo cluster (D=16.5 Mpc) publicly available in the Keck\, Gemini\ , and VLT data archives. For every galaxy we have a spatially resolved opt ical spectrum reaching 1-2 half-light radii from its center. By analyzing these data\, we studied their internal properties\, such as stellar kinema tics (rotation\, velocity dispersion)\, ages and chemical composition of t heir stars (e.g. to estimate when the star formation was quenched)\, and p erform Jeans dynamical modelling\, which yields dark matter content and dy namical masses. Profiles of radial velocity for a dozen of dEs in the Coma cluster demonstrate quite large kinematically decoupled cores suggestive of relatively recent mergers\, which were experienced by these galaxies. W e discuss several various scenarios of dE galaxy formation and evolution b ased on their dynamical masses\, stellar population properties\, internal dynamics and position within the host clusters and put them in corresponde nce with different dE sub-classes. With these data we can directly test th e applicability of the abundance matching to galaxies in clusters in the 3 e8-5e9 MSun range in stellar mass.\n\nhttps://iaus379.aip.de/event/20/cont ributions/280/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/280/ END:VEVENT BEGIN:VEVENT SUMMARY:Low-mass galaxy rotation curves that fail as dynamical mass tracer s DTSTART;VALUE=DATE-TIME:20230323T142800Z DTEND;VALUE=DATE-TIME:20230323T143000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-277@meetings.aip.de DESCRIPTION:Speakers: Kyle Oman (Durham University)\nIt is routinely assum ed that galaxy rotation curves are equal to their circular velocity curves (modulo some corrections) such that they are good dynamical mass tracers. I will present the results of an unconventional\, visualisation-driven an alysis of 33 low-mass field galaxies from the APOSTLE suite of galaxy form ation simulations exploring the limits of the validity of this assumption. Only 4/33 galaxies have HI rotation curves nearly equal to their circular velocity curves\; the rest are undergoing a wide variety of dynamical per turbations of both secular and environmental origin. While some types of p erturbations\, such as ongoing mergers\, have obvious observable signature s\, others\, such as wind from motion through the intergalactic medium\, a re much more subtle. Discrepancies between the rotation curves and circula r velocity curves of low-mass galaxies have direct consequences for key re sults in near-field cosmology. They likely lead to an overestimation of th e low-velocity end of the baryonic Tully-Fisher relation that is difficult to avoid (even by attempting to select 'equilibrium' galaxies)\, and coul d plausibly be the source of a significant portion of the observed diversi ty in low-mass galaxy rotation curve shapes.\n\nhttps://iaus379.aip.de/eve nt/20/contributions/277/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/277/ END:VEVENT BEGIN:VEVENT SUMMARY:The north-south asymmetry of the ALFALFA HI velocity width functio n DTSTART;VALUE=DATE-TIME:20230323T142600Z DTEND;VALUE=DATE-TIME:20230323T142800Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-235@meetings.aip.de DESCRIPTION:Speakers: Richard Brooks (University College London)\nThe numb er density of extragalactic 21-cm radio sources as a function of their spe ctral line-widths -- the HI width function (HI WF) -- is in principle a se nsitive tracer of the dark matter halo mass function (HMF). The Λ cold da rk matter model predicts that the HMF should be identical everywhere provi ded it is sampled in sufficiently large volumes\, implying that the same s hould be true of the HI WF. The ALFALFA 21-cm survey measured the HI WF in two separate\, northern (‘spring') and southern (‘fall') Galactic fie lds and found a systematically higher number density of sources in the spr ing field. Taken at face value\, this is in tension with theoretical predi ctions. Using the Sibelius-DARK N-body simulation and the semi-analytical galaxy formation model GALFORM to create a mock ALFALFA survey\, we find t hat the offset in number density likely has two origins: the sensitivity o f the survey is different in the two survey fields\, which has not been co rrectly accounted for in previous measurements\; and the limited ability o f the $1/V_\\mathrm{eff}$ algorithm used for completeness corrections to m itigate biases arising from spatial clustering in the galaxy distribution. The latter bias is primarily driven by a foreground overdensity in the sp ring field within a distance of 30 Mpc\, but more distant structure also p lays a role. We provide an updated measurement of the ALFALFA HI WF (and H I MF) correcting for the variations in survey sensitivity. Only when syste matic effects such as these are understood and corrected for can the HI WF fulfil its potential as a test of cosmological models.\n\nhttps://iaus379 .aip.de/event/20/contributions/235/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/235/ END:VEVENT BEGIN:VEVENT SUMMARY:Forming Blue Compact Dwarf Galaxy (BCD) through the Merger DTSTART;VALUE=DATE-TIME:20230323T142400Z DTEND;VALUE=DATE-TIME:20230323T142600Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-234@meetings.aip.de DESCRIPTION:Speakers: Daya Nidhi Chhatkuli (Central Department of Physics\ , Tribhuvan University)\nIt has long been speculated that Blue Compact Dwa rf galaxies (BCDs) are formed through the interaction between low-mass gas -rich galaxies\, but due to a lack of evidence\, this possibility has rare ly been explored. We study a sample of compact star-forming dwarf galaxies that are selected from a merging dwarf galaxy catalog. We present a detai led study of their spectroscopic and structural properties. We find that t hese BCDs looking galaxies host extended stellar shells and thus is confir med to be a dwarf-dwarf merger. Their stellar masses range between 8 × 10 7 Mʘ and 2 × 109 Mʘ. Although the extended tail and shell are prominent in the deep optical images\, the overall major axis light profile is well modeled with a two-component Sersic function of inner compact and extende d outer radii. We calculate the inner and outer component stellar-mass rat io using the two-component modeling. We find an average of 4:1 (with a ran ge of 10:1 to 2:1) for our sample\, indicating that these galaxies might h ave suffered a satellite accretion which triggers the starburst in the cen ter of the host galaxies. From the measurement of Hα equivalent width\, w e derived the star-formation ages of these galaxies. The derived star-form ation ages of these galaxies turn out to be less than 100 Myr\, suggesting the recent ignition of star-formation due to events of satellite interact ion.\nKey words: galaxies: evolution-galaxies: irregular-galaxies: dwarf-g alaxies: starburst-galaxies: interactions.\n\nhttps://iaus379.aip.de/event /20/contributions/234/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/234/ END:VEVENT BEGIN:VEVENT SUMMARY:A story of galaxy mass assembly from dynamical modelling of nearby galaxies DTSTART;VALUE=DATE-TIME:20230323T142000Z DTEND;VALUE=DATE-TIME:20230323T142200Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-227@meetings.aip.de DESCRIPTION:Speakers: Sabine Thater (University of Vienna)\nUnderstanding the mass assembly of galaxies is one of the big open questions in astronom y. A dynamical analysis of galaxies of the ATLAS3D survey provides new clu es about the galaxy evolution process of galaxies as the sample comprises a good mix of fast and slow rotators with very different growing scenarios . Slow rotators are thought to accrete about 50 per cent of their stellar mass from satellite galaxies and their most massive progenitors have on av erage up to three major mergers during their evolution. Fast rotators in c ontrast\, accrete less than 50 per cent and have on average less than one major merger in their past. But what is the imprint of the different evolu tionary scenarios on the mass distribution and intrinsic shape of galaxies ?\n\nI will present a detailed dynamical study of the massive fast- and sl ow-rotator galaxies in the ATLAS3D survey with the Schwarzschild code DYNA MITE\, that models galaxies as a superposition of their stellar orbits and colours those orbits with ages and metallicities. Using this full set of observables\, I will quantify how tightly we can constrain the intrinsic s hape and distribution of the visible and invisible matter in nearby early- type galaxies and relate it with the evolutionary scenarios. Compared to p revious studies\, triaxial modelling is essential for these galaxies to un derstand their complex kinematical features. I will conclude the discussio n on what we can learn by comparison with dynamical studies of the Milky W ay in order to learn about the dark past of galaxies.\n\nhttps://iaus379.a ip.de/event/20/contributions/227/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/227/ END:VEVENT BEGIN:VEVENT SUMMARY:Dwarf Properties and Satellite Planes Beyond the Local Volume DTSTART;VALUE=DATE-TIME:20230323T142200Z DTEND;VALUE=DATE-TIME:20230323T142400Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-226@meetings.aip.de DESCRIPTION:Speakers: Nick Heesters (EPFL)\nDwarf galaxies are regarded as the oldest and most numerous galaxy type in the Universe\, responsible fo r the formation of the higher mass galaxies we see today. While we know a lot about the properties of dwarfs in the Local Group as well as selected nearby groups and clusters\, our understanding of these galaxies beyond th e Local Volume is comparatively poor. The properties probed by this restri cted range of locations may be statistically deviant and therefore investi gating these objects in a large variety of density environments is critica l towards a more complete understanding of galaxy formation and evolution. Through the study of dwarfs\, a number of small-scale challenges of the $ \\Lambda$CDM paradigm have emerged over the years. While issues such as th e missing satellite\, the "Too-Big-to-Fail"\, and the cusp-core problem ca n increasingly be resolved by including baryonic physics and by altering t he properties of dark matter\, the so-called planes-of-satellites problem remains unsolved. Dwarf satellite galaxies in our Milky Way and different galaxy systems in the Local Volume appear to be arranged in thin\, vast pl anes. It has been argued that these phase-space correlations can not be ex plained to a satisfactory degree by the standard model of cosmology but it is unclear whether these planes in our neighborhood are statistical outli ers\, or if they are perhaps a common phenomenon in the Universe. Recent d eep imaging surveys have significantly increased the number of known dwarf galaxies and allow us to advance these tensions beyond the Local Volume. I will present our study analyzing the spatial distribution of 2210 dwarf galaxies identified in the MATLAS survey as well as results from follow-up observations with the MUSE instrument on the VLT. Spectral information fo r 56 of these dwarf galaxies\, situated in low-to-medium density environme nts\, allow for a deeper dive into their properties and for a comparison t o the Local Volume dwarfs.\n\nhttps://iaus379.aip.de/event/20/contribution s/226/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/226/ END:VEVENT 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:20241114T092322Z UID:indico-contribution-20-200@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:20241114T092322Z UID:indico-contribution-20-175@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:20241114T092322Z UID:indico-contribution-20-210@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:20241114T092322Z UID:indico-contribution-20-207@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:20241114T092322Z UID:indico-contribution-20-222@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:20241114T092322Z UID:indico-contribution-20-296@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:Decoding Dark Matter with Stellar Streams from Beyond the Milky Wa y DTSTART;VALUE=DATE-TIME:20230323T135500Z DTEND;VALUE=DATE-TIME:20230323T142000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-181@meetings.aip.de DESCRIPTION:Speakers: Sarah Pearson (NYU)\nIn the coming decade\, thousand s of stellar streams will be observed in the halos of external galaxies wi th the Nancy Grace Roman Space Telescope\, the Euclid Space Telescope\, an d the Vera C. Rubin Observatory. Stellar streams form when a dwarf galaxy or a cluster of stars is torn apart due to an underlying galactic potentia l\, leaving behind a swath of thousands of stars that exhibit coherent\, o rdered motion. These streams are sensitive to the distribution of dark mat ter and to the population of dark matter subhalos in galaxies\, both of wh ich depend on the mass and interactions of the dark matter particle. In th is talk\, I discuss how to use the incoming wealth of stellar stream data to rule out dark matter candidates. I first focus on dwarf streams and pre sent new models of the Centaurus A (Cen A) dwarf companion Dwarf 3 (Dw3) a nd Dw3's associated stellar stream. With a novel external galaxy stream-fi tting technique\, I show that there are many viable stream models that fit the data well\, provided that Cen A has a dark matter halo mass larger th an M_200 > 4.7 x 10^12 Msun. I also demonstrate that just one radial veloc ity measurement breaks degeneracies between stream morphology and dark mat ter halo mass. In the second part of the talk\, I discuss stellar streams from globular clusters. Due to their low velocity dispersions\, these stre ams are sensitive to gravitational interactions with low-mass dark matter subhalos. In the Milky Way\, we know of a handful of stellar streams with noticeable under-densities\, however\, the Galactic bar\, molecular clouds \, and spiral arms can also lead to similar signatures in the streams. If we can instead find globular cluster streams in external galaxies without these baryonic perturbers\, gaps in such streams can be easier to decipher and serve as a test of LCDM. I present the Hough Stream Spotter code whic h can rapidly and systematically search for linear structures in external galaxies. The Hough Stream Spotter combined with the Nancy Grace Roman Spa ce Telescope will find hundreds of thin globular cluster streams in extern al galaxies. Lastly\, I will discuss how to use stellar streams as tools t o rule out dark matter candidates that are inconsistent with the new wealt h of data.\n\nhttps://iaus379.aip.de/event/20/contributions/181/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/181/ END:VEVENT BEGIN:VEVENT SUMMARY:The coherent motion of Cen A dwarf satellite galaxies as a challen ge for cosmology DTSTART;VALUE=DATE-TIME:20230324T102000Z DTEND;VALUE=DATE-TIME:20230324T104500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-182@meetings.aip.de DESCRIPTION:Speakers: Oliver Müller (Institute of Physics\, Laboratory of Astrophysics\, École Polytechnique Fédérale de Lausanne (EPFL))\nThe p lane-of-satellites problem is one of the most severe small-scale challenge s for the standard Λ cold dark matter (ΛCDM) cosmological model: Several dwarf galaxies around the Milky Way and Andromeda co-orbit in thin\, plan ar structures. A similar case has been identified around the nearby ellipt ical galaxy Centaurus A (Cen A). We studied the satellite system of Cen A with line-of-sight velocities from VLT/MUSE observations and TRGB distance s from VLT/FORS2 and HST observations. Out of 28 dwarf galaxies with meas ured velocities 21 share a coherent motion and are arranged in a flattened structure. Similarly\, flattened and coherently moving structures are fou nd only in 0.2% of Cen A analogs in the Illustris-TNG100 cosmological simu lation\, independently of whether we use its dark-matter-only or hydrodyna mical run. These analogs are not co-orbiting\, and they arise only by chan ce projection\, thus they are short-lived structures in such simulations. Our findings indicate that the observed co-rotating planes of satellites a re a persistent challenge for ΛCDM\, which is largely independent from ba ryon physics.\n\nhttps://iaus379.aip.de/event/20/contributions/182/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/182/ END:VEVENT BEGIN:VEVENT SUMMARY:Too Big to Fail? 6D Stellar Streams in the Milky Way and Cosmologi cal Simulations DTSTART;VALUE=DATE-TIME:20230324T092500Z DTEND;VALUE=DATE-TIME:20230324T094000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-219@meetings.aip.de DESCRIPTION:Speakers: Nora Shipp (Massachusetts Institute of Technology)\n Recent large photometric\, astrometric\, and spectroscopic surveys have en abled the first systematic observations of Milky Way stellar streams in 6D . At the same time\, cutting edge cosmological simulations are now at reso lutions that allow for the study of dwarf galaxy streams around Milky Way- like hosts. In this talk\, I will present the discovery and characterizati on of a population of 6D stellar streams with observations from the Dark E nergy Survey\, Gaia\, and the Southern Stellar Stream Spectroscopic Survey (S5) in comparison to streams identified in cosmological simulations. The se comparisons enable deeper studies of satellite populations and tidal di sruption in simulations and observations\, and further tests of the small- scale challenges to LCDM.\n\nhttps://iaus379.aip.de/event/20/contributions /219/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/219/ END:VEVENT BEGIN:VEVENT SUMMARY:The Triangulum Extended Survey: Insights into the Dynamical Histor y of M33 and M31 DTSTART;VALUE=DATE-TIME:20230321T133000Z DTEND;VALUE=DATE-TIME:20230321T134500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-191@meetings.aip.de DESCRIPTION:Speakers: Karoline Gilbert (Space Telescope Science Institute) \nTriangulum (M33)\, a satellite of the Andromeda (M31) galaxy\, is the on ly dwarf Spiral in the Local Group. With a mass ten times lower than M31 ’s and a star formation rate 10 times higher\, M33 is the best local ana log for high z galaxies. The Triangulum Extended Survey (TREX) is a large resolved stellar spectroscopic survey of M33 and its extended structures. With contiguous spectroscopic fields covering M33's inner disk\, out to M 33's disk break\, and beyond\, we are investigating the evidence for both internal and external heating mechanisms affecting M33. Using a sample of over 4500 M33 stars with line of sight velocity measurements\, spanning f rom young\, massive main sequence stars to old red giant branch stars\, we established that a significant high-velocity-dispersion component is pres ent in M33's RGB population from near M33's center to at least the radius where M33's H I disk begins to warp at 30' (~7.5 kpc) in the plane of the disk. This is the first detection and spatial characterization of a kinema tically hot stellar component throughout M33's inner regions. However\, b eyond the break in M33's disk\, we find the stellar population is dominate d by stars with disk-like kinematics\, with only marginal evidence for a k inematically hot halo component\, casting doubt onto whether this componen t is likely to have been formed from accretion of smaller systems. We ha ve also measured the velocity dispersion and asymmetric drift of stars in the disk as a function of stellar age\, finding neither increases with ste llar age and the youngest disk stars are dynamically hotter than predicted by simulated M33 analogs in Illustris. This indicates an additional\, cur rently unknown source of dynamical heating of the young stars in the disk of M33. I will discuss these TREX results\, as well as future prospects\, in the context of our understanding of the orbital history of M33\, in p articular\, the question of whether M33 is on first infall or has interact ed substantially with M31 in the past.\n\nhttps://iaus379.aip.de/event/20/ contributions/191/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/191/ END:VEVENT BEGIN:VEVENT SUMMARY:Galaxy masses derived from the timing argument DTSTART;VALUE=DATE-TIME:20230321T114000Z DTEND;VALUE=DATE-TIME:20230321T120500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-180@meetings.aip.de DESCRIPTION:Speakers: Jorge Peñarrubia (University of Edinburgh)\nThe rat her intuitive concept of 'galaxy mass' is an ill-defined quantity in cosmo logy. First\, because in an expanding\, close-to-homogeneous Universe coll apsed structures do not show well-defined boundaries\, and second because the availability of dynamical tracers becomes very scarce in the outskirts of dark matter haloes. In this talk I will provide an overview of the tim ing argument\, which models the relative motion of massive substructures i n an expanding Universe as a restricted 3-body system. I will show that th is method returns masses that are systematically higher than the mass encl osed within the nominal virial radius of a galaxy\, thus complicating a di rect comparison with 'dynamical' masses derived from halo tracers. As an a pplication\, I will summarize recent attempts to measure simultaneously th e masses of our Galaxy\, the Large Magellanic Cloud and M31.\n\nhttps://ia us379.aip.de/event/20/contributions/180/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/180/ 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:20241114T092322Z UID:indico-contribution-20-295@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:20241114T092322Z UID:indico-contribution-20-294@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:Small-scale stellar haloes: detecting extended substructure in the outskirts of Milky Way dwarf galaxy satellites DTSTART;VALUE=DATE-TIME:20230322T104500Z DTEND;VALUE=DATE-TIME:20230322T110000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-198@meetings.aip.de DESCRIPTION:Speakers: Jaclyn Jensen (University of Victoria)\nDwarf galaxi es are valuable laboratories for dynamical studies related to dark matter and galaxy evolution\, yet it is currently unknown just how extended their stellar components are. Each satellite orbiting within the Milky Way’s (MW’s) gravitational potential may undergo tidal stripping by the host g alaxy\, or alternatively\, may themselves have accreted yet smaller system s whose debris settles into the satellite’s own stellar halo. Both proce sses could mean that significant populations of member stars are found far from the center of the dwarf. Stars in the outskirts of these systems are especially valuable – and rare – tracers of the dwarf’s dynamics in low acceleration regimes\, and they give insight into the dwarf’s evolu tionary history. In this work\, we examine the MW’s ~60 dwarf satellites to search for these rare\, distant member stars. Using Gaia eDR3 and a ma ximum likelihood approach allowing for multi-component extended substructu res\, we find 9 dwarfs that exhibit a secondary\, lower-density\, outer pr ofile\, that we argue is indicative of an extended stellar halo and/or tid al disruption. Our method shows excellent consistency with spectroscopical ly confirmed members from the literature and requires no radial velocity i nformation. For each dwarf galaxy\, we derive a sample of high-confidence members which will prove useful for studying even the faintest MW dwarfs. We also briefly discuss a current spectroscopic follow-up campaign for the most radially distant outskirt members\, which will feature the newly com missioned Gemini High-resolution Optical SpecTrograph (GHOST). Already\, i nitial spectra obtained during GHOST commissioning has proven useful for c omprehensive chemodynamics of these Galactic building blocks.\n\nhttps://i aus379.aip.de/event/20/contributions/198/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/198/ END:VEVENT BEGIN:VEVENT SUMMARY:Constraining the Total Mass of M31 with Precision Astrometry DTSTART;VALUE=DATE-TIME:20230321T105500Z DTEND;VALUE=DATE-TIME:20230321T111000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-192@meetings.aip.de DESCRIPTION:Speakers: Ekta Patel (UC Berkeley)\nHigh-precision astrometric data from the Hubble Space Telescope (HST) and Gaia are revolutionizing o ur ability to study the Local Group. Currently\, 6D phase space measuremen ts (3-dimensional position and velocity) are available for a majority of t he Milky Way’s known satellite galaxies and for four (11%) of M31’s sa tellite galaxies. As satellites trace the dark matter halos of their hosts \, often\, the dynamical properties of a given satellite are used to const rain the mass of the Milky Way (MW) or M31. However\, my recent work has s hown that using the 6D phase space information for an ensemble of satellit e galaxies simultaneously can significantly reduce the current factor of t wo uncertainty in the mass range of the MW. In this talk\, I will describe how dynamical properties derived from 6D phase space information of four M31 satellites (M33\, IC 10\, NGC 147\, NGC 185) can be used in combinatio n with state-of-the-art cosmological simulations to statistically estimate the mass of M31\, reducing current uncertainties to 30-60%. Over the next decade\, HST will deliver astrometric data for the remainder of M31’s s atellite population. Applying these methods to the full population of sate llites out to ~300 kpc will yield the most precise and complete M31 mass e stimate to date. This will be a crucial result for interpreting the severi ty of classical small-scale LCDM challenges (i.e. missing satellites\, too -big-to-fail)\, the assembly history of M31\, and the fate of the Local Gr oup.\n\nhttps://iaus379.aip.de/event/20/contributions/192/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/192/ END:VEVENT BEGIN:VEVENT SUMMARY:Dynamical properties of ancient stars in the inner Milky Way with PIGS DTSTART;VALUE=DATE-TIME:20230320T164000Z DTEND;VALUE=DATE-TIME:20230320T165500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-195@meetings.aip.de DESCRIPTION:Speakers: Anke Arentsen (Institute of Astronomy\, Cambridge)\n The oldest\, most metal-poor stars in the Milky Way are unique probes of e arly star formation and the assembly of the Milky Way. The Galactic bulge region has typically been avoided in the search for metal-poor stars\, bec ause of the extremely high density of mostly metal-rich stars and the high dust extinction. The bulk of the Galactic bulge is thought to originate f rom the (early) Galactic disk. However\, the oldest pressure-supported com ponent in our Galaxy is also expected to be present in its innermost regio n. The most metal-poor stars in the bulge region can provide unique insigh ts into the ancient Milky Way. \n\nI will present results from the Pristin e Inner Galaxy Survey (PIGS)\, which used metallicity-sensitive narrow-ban d CaHK photometry to identify and follow up spectroscopically thousands of metal-poor candidates in the bulge. Using the bulk PIGS radial velocities \, we previously showed that the amount of inner Galaxy rotation decreases with decreasing metallicity. I will present recent work on the detailed o rbital properties for all stars in PIGS\, which strongly depend on their m etallicities and broadly show a transition from a disky bulge to a pressur e-supported component. It is exciting to see the growing amount of data on metal-poor stars in the inner regions of the Milky Way\, thanks to variou s surveys\, allowing us to set important constraints on the formation of t he ancient inner Galaxy.\n\nhttps://iaus379.aip.de/event/20/contributions/ 195/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/195/ END:VEVENT BEGIN:VEVENT SUMMARY:The study of the Galactic mass distribution from Gaia DR3 RR Lyrae DTSTART;VALUE=DATE-TIME:20230321T081500Z DTEND;VALUE=DATE-TIME:20230321T083000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-223@meetings.aip.de DESCRIPTION:Speakers: Cuihua Du ()\nThe mass of the Milky Way (MW) is impo rtant to the formation and evolution of galaxy. After decades of study\, t he mass of dark matter halo is still open. Most studies have used dynamic al tracers in the inner regions of the halo\, relying on extrapolations to estimate the mass of the MW. In our study\, we determine the Milky Way ma ss distribution from fitting dynamical models to the gravitational force f ield and the Galactic rotation curve. Based on RR Lyrae with accurate pro per motions and classification in Gaia DR3\, we obtain the distance with r elative uncertainty less than 5% by using the extinction-free Period-Wesen heit relation. Applying Gaussian Mixture Model to the intrinsic velocity d istribution\, we present the result of a multi-component kinematic model o f RR Lyrae in the inner regions. Considering the early accretion history o f the MW so that the stellar halo may not be in equilibrium\, we separate the halo population into an isotropic stellar halo and the radially-anisot ropic population relevant to a merge event. With a Bayesian method\, we f it the potential model parameters\, including the density flattening of th e dark matter (DM) halo. \nIn this talk\, I shall discuss our best-fitting results about the shape and DM halo mass.\n\nhttps://iaus379.aip.de/event /20/contributions/223/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/223/ END:VEVENT BEGIN:VEVENT SUMMARY:Large-scale gas flows in the Local Group DTSTART;VALUE=DATE-TIME:20230323T103000Z DTEND;VALUE=DATE-TIME:20230323T104500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-212@meetings.aip.de DESCRIPTION:Speakers: Philipp Richter (University of Potsdam)\nIn this tal k\, I will discuss recent UV absorption-line measurements of large-scale g as flows in the Local Group with particular emphasis on the relation betwe en LG galaxy kinematics and CGM/IGrM gas dynamics. New results from an HST /COS all-sky survey of gas in the Milky Way's CGM and the Local Group IGrM will be presented and compared with predictions from the HESTIA simulatio ns .\n\nhttps://iaus379.aip.de/event/20/contributions/212/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/212/ END:VEVENT BEGIN:VEVENT SUMMARY:The dynamical mass of the Large Magellanic Cloud as measured by it s system of star clusters DTSTART;VALUE=DATE-TIME:20230323T101500Z DTEND;VALUE=DATE-TIME:20230323T103000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-206@meetings.aip.de DESCRIPTION:Speakers: Florian Niederhofer (Leibniz-Institut für Astrophys ik Potsdam (AIP))\nThe Large and Small Magellanic Clouds (LMC and SMC) are the largest and most luminous dwarf satellite companions of the Milky Way . Due to their close proximity\, they provide a unique opportunity to stud y the dynamics of their resolved stellar populations in unparalleled detai l. Within the last years\, high-precision proper motion measurements of st ars within the Magellanic Clouds had a tremendous impact on our understand ing of the Magellanic system and its relation to our own Galaxy. To date\, however\, the dynamics of the star cluster systems within the two dwarf g alaxies has not received much attention. \nIn this contribution\, I will i ntroduce an ongoing observational campaign conducted by our team utilising the Hubble Space Telescope (HST) to precisely measure the proper motions of star clusters within the LMC. The exquisite resolution of HST allows us to measure precise proper motions of thousands of stars within each clust er.\nThe measured motions of the clusters\, combined with photometric and spectroscopic measurements\, will yield their full 6-dimensional phase spa ce information within the LMC. I will present first results of the kinemat ic structures that are described by clusters of various ages and within di fferent structural components of the galaxy. The motions of the clusters c an further act as a tracer of the gravitational potential of the LMC and I will present preliminary measurements of the mass of the LMC resulting fr om the dynamics of the star clusters. Despite its importance in the field of Magellanic Cloud kinematics and evolution\, the mass of the LMC is only vaguely known and several studies disagree on it. Our cluster-based study will provide an additional independent measurement of the LMC's mass.\n\n https://iaus379.aip.de/event/20/contributions/206/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/206/ END:VEVENT BEGIN:VEVENT SUMMARY:The stellar halo’s response as a probe of the LMC to MW mass rat io DTSTART;VALUE=DATE-TIME:20230323T082500Z DTEND;VALUE=DATE-TIME:20230323T084000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-187@meetings.aip.de DESCRIPTION:Speakers: Simon Rozier (Observatoire Astronomique de Strasbour g)\nIn the last two decades\, some arguments have accumulated for a more i mportant mass ratio of the Large Magellanic Cloud (LMC) to the Milky Way ( MW) than was previously thought\, of about 10% or more. This implies that the LMC has a measurable influence on the dynamics in the MW stellar halo\ , including both stellar densities and kinematics\, as observed by Conroy *et al.* (2021) and Petersen *et al.* (2021). While this merger has been p reviously reproduced using N-body simulations (see\, e.g.\, Garavito-Camar go *et al.*\, 2019)\, I will present the results of a recent study (Rozier *et al.*\, 2022) which aimed at modelling the merger via linear response theory. More specifically\, we integrated the linearized collisionless Bol tzmann-Poisson system of partial differential equations using a methodolog y known as the matrix method. Our results display the same large scale beh aviour as state-of-the-art simulations\, with a dipolar over/underdense pa ttern related to the reflex motion of the MW\, as well as an overdense wak e trailing behind the LMC. These results represent an efficient way of con straining the LMC to MW mass ratio\, since this ratio is directly proporti onal (given the linear nature of the theory) to the amplitude of the relat ive density variations of the MW stellar halo\, both in physical and in ph ase space. However\, the amplitude of these variations may also depend on some model parameters\, such as the structure of the MW potential (includi ng a possible dark matter component)\, the initial density distribution of the stellar halo\, as well as its initial internal kinematics. I will foc us on the latter source of degeneracy\, showing how the initial velocity a nisotropy of the stellar halo impacts its response to the LMC. Interesting ly enough\, it appears that the physical space density of the (dipolar) re flex motion is insensitive to the stellar halo’s initial velocity anisot ropy\, and can therefore represent an efficient probe of the LMC to MW mas s ratio.\n\nhttps://iaus379.aip.de/event/20/contributions/187/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/187/ END:VEVENT BEGIN:VEVENT SUMMARY:Dynamical evolution of the sub-galactic dark matter halos and the effect of the cusp-to-core transformation DTSTART;VALUE=DATE-TIME:20230322T093300Z DTEND;VALUE=DATE-TIME:20230322T093500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-266@meetings.aip.de DESCRIPTION:Speakers: Yuka Kaneda (University of Tsukuba)\nIn the hierarch ical clustering scenario based on the $\\Lambda$ cold dark matter ($\\Lamb da$CDM) model\, sub-galactic dark matter halos (subhalos) are of crucial i mportance in building up the larger structures via merging processes. More over\, dwarf galaxies around the Milky Way (MW) are ideal sites for studyi ng the nature of dark matter since they are dark-matter-dominated systems. \n\nWe investigate the mass evolution histories and the evolutional track s on the $r_\\mathrm{max}$-$V_\\mathrm{max}$ plane of the subhalos associa ted with MW-sized host halos based on the ultra-high resolution cosmologic al $N$-body simulation\, Phi-4096 by Ishiyama et al. (2021)\, where $V_\\m athrm{max}$ and $r_\\mathrm{max}$ denote the maximum circular velocity and the radii where the circular velocity becomes $V_\\mathrm{max}$\, respect ively. We report that the evolutional tracks of dwarf-galaxy-mass halos sh ow an interesting feature compared to the ones of massive halos shown in t he literature. The mass evolution of subhalos clearly shows two phases: th e accretion phase and the stripping phase. First\, more than 90% of our sa mple subhalos increase their masses gradually until the redshift $z=1-2$ ( accretion phase)\, and then the masses decrease due to the tidal stripping driven by the host halo (stripping phase). Thus\, we show quantitatively that tidal stripping plays an essential role in the dynamical evolution of subhalos.\n\nIn addition\, the mass density profile of subhalos has a lon g-standing disagreement between the observations and the predictions by th e pure CDM simulations\, known as the cusp-core problem. Standing on a hyp othesis that DM halos are formed primarily with central cusps and then som e dynamical processes lead them to form cores\, we provide a ‘core-to-cu sp transformation model’ that reverts the properties of cored profile to ones of the cusp profile. In constructing a model\, some appropriate cond itions are imposed about how the transition should occur\, and detailed ph ysical processes are not considered here. The reverted observational prope rties\, including $r_\\mathrm{max}$ and $V_\\mathrm{max}$\, show excellent agreement with the theoretical prediction from the cosmological $N$-body simulation. This result supports the description that the CDM creates init ial cusps in the centre of DM halos\, and some dynamical process gives ris e to the cusp-to-core transformation.\n\nhttps://iaus379.aip.de/event/20/c ontributions/266/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/266/ END:VEVENT BEGIN:VEVENT SUMMARY:The Cosmic Hunt for Members in the Outskirts of Ultra Faint Dwarf Galaxies: Ursa Major I\, Coma Berenices\, and Boötes I DTSTART;VALUE=DATE-TIME:20230322T093100Z DTEND;VALUE=DATE-TIME:20230322T093300Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-264@meetings.aip.de DESCRIPTION:Speakers: Fletcher Waller (University of Victoria)\nThe chemic al abundance patterns exhibited by stars in Ultra-Faint Dwarf (UFD) galaxi es can provide a wealth of information about the evolutionary history of U FDs\, including what dynamical history the stars in a UFD may have experie nced. Of particular interest are stars in the outer regions of UFDs becaus e they may hold evidence of tidal stripping\, mergers\, or other mechanism s\; and because of the localized nature of enrichment events in UFDs\, it is important to use every available star in analyses of UFD histories. I p resent detailed abundances from high-resolution spectroscopy with Gemini/G RACES for five new stars in three UFDs\, Coma Berenices (Com Ber)\, Ursa M ajor I (UMaI)\, and Boötes I (BooI)\, where four of our five stars are at distances greater than two half-light radii. The chemistries for all thre e galaxies are consistent with the outermost stars forming in the central regions\, then moving to their current locations through dynamical mechani sms. In BooI\, the lower metallicity and lack of strong carbon enrichment of its outermost stars could also be evidence of a dwarf galaxy merger. Th e abundance ratios and chemical patterns of the stars in Com Ber are consi stent with contributions from SN Ia (including an unusually high Ni value) \, which is unexpected for its star formation history and in conflict with previous suggestions that this system evolved chemically from a single co re collapse supernova event. We look forward to the new GHOST (Gemini High -resolution Optical SpecTrograph)\, which will make these types of chemica l abundance-quality observations possible for many more stars in UFDs.\n\n https://iaus379.aip.de/event/20/contributions/264/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/264/ END:VEVENT BEGIN:VEVENT SUMMARY:The Magellanic System DTSTART;VALUE=DATE-TIME:20230322T155000Z DTEND;VALUE=DATE-TIME:20230322T163000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-290@meetings.aip.de DESCRIPTION:Speakers: Elena d’Onghia (UNIVERSITY of WISCONSIN–MADISON) \nThe Magellanic Stream is the most spectacular example of a gaseous strea m in the local Universe. In this review I will discuss the Stream's import ance for many areas of Galactic astronomy\, summarize key unanswered quest ions\, and identify future observations and simulations needed to resolve them.\n\nhttps://iaus379.aip.de/event/20/contributions/290/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/290/ END:VEVENT BEGIN:VEVENT SUMMARY:Spatio- temporal formation history and kinematics of star clusters in the Magellanic Clouds: Propagation of cluster formation and the LMC ba r DTSTART;VALUE=DATE-TIME:20230322T145900Z DTEND;VALUE=DATE-TIME:20230322T150100Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-276@meetings.aip.de DESCRIPTION:Speakers: Dhanush Sathiavals Reselammal (Senior Research fello w\, IIA)\nThe Large Magellanic cloud(LMC) and Small Magellanic cloud(SMC) are the nearest interacting dwarf galaxies in the local group. And Magell anic clouds(MCs) have had interactions with each other as well as with the Milky Way. These interactions have triggered star formation in both galax ies\, resulting in the formation of star clusters. Thus a comprehensive an alysis of cluster population in MCs could indicate the structural evolutio n due to galaxy mergers. Our aim is to understand the age dating\, spatio- temporal map of cluster formation episodes\, and trace the cluster kinemat ics as a function of age.\nIn this study\, we used the GAIA DR3 data to ch aracterise the cluster population in the MCs. The clusters in the MCs is o btained mostly from general catalogue given by Bica et al. (2020)\, and se veral other recent literature. We classified the clusters as isolated and merged based on projected sky coordinates. Around 2000 clusters were analy zed in our study based on a certain selection criteria. We used Gaia async hronous query to bulk handle the cluster data from Gaia archive\, after ap plying proper motion-parallax cut offs and faintness magnitude limit. We d eveloped a statistical algorithm to remove filed stars from the cluster re gion. We used single to multiple comparison field regions and retrieved th e most probable cluster members. Using Padova-Parsec stellar evolutionary models\, we performed an iterative least square method to estimate the ag e and reddening of clusters that had sufficient members and a satisfactory fit of the isochrone. The spatio-temporal map of age and reddening was ob tained for clusters in both clouds. We traced the cluster formation episod es at ~ 1.6 Gyr\, 630 Myr\, 310 Myr\, and 80 Myr. The directional propagat ion of cluster formation is noted from the South to North of LMC over the time scale of 2.8 Gyr to 10 Myr. We are able to estimate the formation ti me of the LMC’s off-centered bar. Using the proper motion data of the m embers we also study the proper motion of the clusters with respect to the field population in both the Clouds.\n\nhttps://iaus379.aip.de/event/20/c ontributions/276/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/276/ END:VEVENT BEGIN:VEVENT SUMMARY:Tracing the structure and history of the Small Magellanic Cloud us ing CaII Triplet spectroscopy DTSTART;VALUE=DATE-TIME:20230322T150100Z DTEND;VALUE=DATE-TIME:20230322T150300Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-275@meetings.aip.de DESCRIPTION:Speakers: Mahdieh Navabi (The University of Surrey)\nThe Small Magellanic Cloud (SMC)\, as one of the nearest galaxies to us\, provides a superb laboratory for studying its stellar populations in exquisite deta il. We collected the largest sample of SMC red giant branch (RGB) stars ( ~6000) observed using the AAOmega spectrograph fed by the Two Degree Field (2dF) multi-object system at the Anglo-Australian Telescope of the Siding Spring Observatory (Australia). The metallicities were recovered using a direct estimation of [Fe/H] from the equivalent widths of the Calcium tri plet (CaT). We discuss the potential implications of the metallicity gradi ents and compare these to previous determinations of star formation histor ies to assess the consequences of encounters between the SMC and Large Mag ellanic Cloud.\n **Finally\, we discuss our findings in the context of the correlation that exists between metallicity and dynamical mass in dwarf I rregular systems\, of which the SMC is our closest example.**\n\nhttps://i aus379.aip.de/event/20/contributions/275/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/275/ END:VEVENT BEGIN:VEVENT SUMMARY:Stromgren photometric metallicity map of the Small Magellanic Clou d using Gaia DR3-XP spectra. DTSTART;VALUE=DATE-TIME:20230322T145700Z DTEND;VALUE=DATE-TIME:20230322T145900Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-274@meetings.aip.de DESCRIPTION:Speakers: Abinaya Ondivillu Omkumar (Leibniz Institute for Ast rophysics Potsdam (AIP))\nObservational studies have identified several su b-structures in different regions of the Magellanic Clouds (MCs). One such interesting sub-structure in the Small Magellanic Cloud (SMC) is a dual p opulation of intermediate-age giant stars which are spatially and kinemati cally distinct. Comparisons with simulations suggest that the foreground p opulation might be tidally stripped from the SMC main-body\, but their ori gin is not clearly proven yet. If we have homogeneous metallicity measurem ents of the sources from these sub-structures\, we can see whether they ar e having similar values or different from the main-body population. Hence\ , metallicity measurements of these populations will help us understand th eir origin and/or their association with the Large Magellanic Cloud (LMC). However\, spectroscopic metallicities are only available for a few thousa nd sources and also from different instruments at various spectral resolut ions\, which makes it difficult to compare their values and draw conclusio ns from the results. The third data release of Gaia has provided us with ~ 0.17 million XP spectra of the SMC sources as faint as ~ 18 mag in G-band which are spread across ~ 10° from the SMC center. Stromgren photometry is a well-established method to estimate the photometric metallicities. Ga ia BP spectra covers the u\, v\, b and y Strömgren bands. Using the estim ated Strömgren magnitudes from the Gaia BP spectra\, we calibrated the [F e/H] values. We compared a subset of the SMC sources that has [Fe/H] value s from the high-resolution (~ 22\,500) APOGEE spectrograph for the validat ion of our method. Using those metallicity measurements\, we produce a hom ogeneous metallicity map of the entire SMC also with a higher spatial reso lution and study the metallicity of different sub-structures to shed light on their possible origin and/or their associations with the LMC.\n\nhttps ://iaus379.aip.de/event/20/contributions/274/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/274/ END:VEVENT BEGIN:VEVENT SUMMARY:Ages\, metallicities and structure of stellar clusters in the Mage llanic Bridge DTSTART;VALUE=DATE-TIME:20230322T145500Z DTEND;VALUE=DATE-TIME:20230322T145700Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-233@meetings.aip.de DESCRIPTION:Speakers: Raphael A. P. Oliveira (IAG - USP)\nThe Magellanic B ridge is a tidally-stripped structure located between the Magellanic Cloud s and contains hundreds of stellar clusters and associations\, which can h elp understanding the origin and evolution of the entire Magellanic Clouds -Milky Way (MW) system. Two main competing models describe the formation o f the pair LMC-SMC: the LMC captured the SMC about 2 Gyr ago and they are in a bound orbit around the MW\, or it is an old interacting sys- tem in i ts first perigalactic passage\, falling into the MW potential ~2 Gyr ago. The Bridge should have been formed during a collision between the Clouds a round 200 Myr ago\, imply- ing kinematic signatures\, as well as age and m etallicity gradients along its extension. This work combines deep photomet ric data from VISCACHA and SMASH surveys in order to ex- plore this questi on\, by homogeneously deriving age\, metallicity\, distance\, structural p arame- ters and mass of 35 Bridge objects with modern statistical tools su ch as Markov chain Monte Carlo and machine learning. In particular\, the m ass determination corrected by completeness can help to estimate the Bridg e stellar mass and constrain the dynamical models. A spectro- scopic follo w-up in the CaII triplet region is also carried out for clusters older tha n 1 Gyr in the Bridge and other SMC regions\, to derive metallicity and ra dial velocity which\, combined with Gaia proper motions\, allow us to obta in a 6D phase-space vector. Preliminary results show a good agreement betw een VISCACHA and SMASH data and also that\, despite the presence of some o ld objects at larger distances\, the clusters in the middle of the Bridge are younger (~ 10-100 Myr) and more metal-rich than those closer to the SM C Wing. In this poster\, we will review the recent results of the VISCACHA collaboration\, present a detailed approach to age and metallicity gradie nts in the Bridge\, and discuss the evidence on the most probable for- mat ion model of the pair LMC-SMC.\n\nhttps://iaus379.aip.de/event/20/contribu tions/233/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/233/ END:VEVENT BEGIN:VEVENT SUMMARY:Exploring the kinematics of the Magellanic stellar periphery DTSTART;VALUE=DATE-TIME:20230322T143000Z DTEND;VALUE=DATE-TIME:20230322T145500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-179@meetings.aip.de DESCRIPTION:Speakers: Lara Cullinane (JHU)\nRecent panoramic maps of the M agellanic system have revealed a wealth of low-surface-brightness stellar substructures surrounding both the Large and Small Magellanic Clouds (LMC/ SMC)\; clear evidence of tidal interactions between the two Clouds\, as we ll as with the Milky Way. However\, the interaction history of the Magella nic system beyond the most recent LMC/SMC close passage remains poorly con strained. In order to shed light on this issue\, we have instigated a larg e-scale spectroscopic follow-up of stars in low-density features extending to distances beyond 20 degrees from the Clouds’ centres. We use a combi nation of Gaia astrometry and spectroscopically-derived radial velocities\ , obtained with 2dF+AAOmega on the Anglo-Australian Telescope\, to determi ne 3D kinematics for thousands of stars in these features and the extended outer disks of the two Clouds. In this talk\, I will discuss new results focussed on the southern outskirts of the LMC. Several substructures in th is region\, including claw-like features extending from the southern LMC d isk\, and a long arm-like substructure wrapping around the southern LMC ou tskirts toward the eastern SMC disk\, are found to be predominantly compos ed of perturbed LMC disk material. All substructures show significant pert urbations from equilibrium disk kinematics\, with one claw-like feature di splaying out-of-plane velocities exceeding 60 km/s and apparent counter-ro tation relative to the LMC’s disk. Such complex features plausibly requi re multiple previous interactions with the SMC to fully explain the observ ed dynamical properties. This demonstrates the efficacy of our data as a b enchmark for assessing dynamical models to disentangle the origins of Mage llanic substructures\, the masses of the two Clouds\, and the evolution of the Magellanic system. I will also briefly discuss new efforts to conduct analogous kinematic mapping of M33 and its outskirts\, which aim to simil arly understand the evolution of this massive dwarf galaxy.\n\nhttps://iau s379.aip.de/event/20/contributions/179/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/179/ END:VEVENT BEGIN:VEVENT SUMMARY:The impact of massive satellites on the kinematic properties of th e Local Group satellite galaxies DTSTART;VALUE=DATE-TIME:20230323T085500Z DTEND;VALUE=DATE-TIME:20230323T091000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-211@meetings.aip.de DESCRIPTION:Speakers: Nicolas Garavito Camargo (Flatiron Institute)\nThe v ast multidimensional data observed in the Local Group (LG) provide us with the unique opportunity of comparing the properties of the LG with their s imulated analogs in cosmological simulations. In such a comparison it has been found that the observed kinematic properties of satellite galaxies in the LG are very unusual when compared to cosmological simulations. In bot h the Milky Way and the Andromeda galaxy\, satellite galaxies are found to be distributed and moving in flattened co-rotating systems. A configurati on that is only found in 0.3-3% of the simulated galaxies. Such disagreeme nt is known as the planes of satellites problem. More intriguing is that t he disagreement is persistent even in different dark matter models and unl ike other 'small-scale problems' it is not sensitive to the inclusion of b aryonic processes in the simulations. \n\nIn this talk\, I would provide n ew evidence of how a natural explanation of the observed co-rotation patte rns are associated with the out-of-equilibrium state of the galaxy. Recen t missions and surveys\, such as Gaia\, have revealed that the Milky Way g alaxy is not in dynamical equilibrium. The barycenter of the galaxy is mov ing due to the ongoing interaction with the Large Magellanic Cloud. Using the Latte hydrodynamical high-resolution zoom-in simulation of MW-like gal axies A massive satellite moves the reference frame of the inner halo wit h respect to the outer halo. Resulting in some cases in apparent co-rotati on motions of the outer halo when observed from the disk of the galaxies. I'll show how the orbital poles distribution of outer halo objects is stro ngly affected during the pericenter passages. I will further discuss what properties of the mergers\, mass ratios\, pericenter passages\, and eccent ricities\, would be needed to reproduce the observational co-rotations pat tern observed in the Milky Way and M31.\n\nThese results provide new insig ht into how the observed co-ration patterns can inform us about the out-of -equilibrium stare of the galaxy. Which is a natural explanation that does not depend on the nature of the Dark Matter particle and in baryonic proc esses. In the talk\, I will also discuss the importance of taking into acc ount the dynamic state of the LG when comparing it with LG analogs in cosm ological simulations.\n\nhttps://iaus379.aip.de/event/20/contributions/211 / LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/211/ END:VEVENT BEGIN:VEVENT SUMMARY:The Mass of the Large Magellanic Cloud DTSTART;VALUE=DATE-TIME:20230322T163000Z DTEND;VALUE=DATE-TIME:20230322T164500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-205@meetings.aip.de DESCRIPTION:Speakers: Laura Watkins (AURA for ESA\, STScI)\nThe Large Mage llanic Cloud (LMC) is the largest of the dwarf galaxies orbiting the Milky Way (MW). It sits in a very interesting niche within the Local Group (LG) \, being both sufficiently different in mass than the MW to be an interest ing comparison and sufficiently massive to be a major player in the MW's r ecent history and present state. In particular\, it is massive enough to h ave a significant and observable effect on the MW itself and on stellar st reams in the MW halo\, though the extent of its influence depends on its m ass. Its mass is also interesting as a benchmark against which we can inte rpret observations of more distant objects.\n\nBennet et al. (2022) recent ly measured proper motions (PMs) -- using HST\, Gaia or both HST and Gaia together -- for a set of globular clusters (GCs) in the LMC. Supplemented with literature distances and line-of-sight velocities\, this provides a c atalogue of 6D phase space information for 32 LMC GCs. These are ideal dyn amical tracers of the LMC’s potential.\n\nIn my talk\, I will describe h ow we have used this set of tracers to estimate the anisotropy and mass of the LMC within 13 kpc\, and then how we have used these estimates to extr apolate the LMC’s virial mass. This is the first time that this family o f mass estimation methods has been applied to the LMC\, and I will also co mpare our estimate against other estimates of the LMC’s mass via differe nt methods and discuss the broader context of our results.\n\nhttps://iaus 379.aip.de/event/20/contributions/205/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/205/ END:VEVENT BEGIN:VEVENT SUMMARY:Velocity dipoles in the halos of FIRE simulated galaxies DTSTART;VALUE=DATE-TIME:20230323T091600Z DTEND;VALUE=DATE-TIME:20230323T091800Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-273@meetings.aip.de DESCRIPTION:Speakers: Alex Riley (Durham University)\nOne major source of disequilibrium in the Milky Way is its most massive satellite\, the LMC. K inematics of distant halo tracers show a velocity dipole in the Milky Way halo\, which has been interpreted using N-body simulations as the LMC indu cing a reflex motion in the Milky Way disk. In this talk\, I discuss apply ing this framework to more realistic halos comprised of substructure from the FIRE-2 zoom-in cosmological simulations. Velocity dipoles are resolved in Milky Way-mass hosts experiencing an LMC-like interaction and evolve i n a manner consistent with a two-body interaction between the stellar disk and the LMC analog. The magnitude of this dipole can be used to constrain the mass ratio of the Milky Way and LMC. However\, satellite galaxies and stellar streams can create velocity dipoles in systems that aren't experi encing a major satellite accretion\, suggesting that care must be taken to remove substructure in the Milky Way observations.\n\nhttps://iaus379.aip .de/event/20/contributions/273/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/273/ END:VEVENT BEGIN:VEVENT SUMMARY:SMASHing the Small Magellanic Cloud: star formation history DTSTART;VALUE=DATE-TIME:20230323T091400Z DTEND;VALUE=DATE-TIME:20230323T091600Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-272@meetings.aip.de DESCRIPTION:Speakers: Sakowska Joanna (University of Surrey)\nI present wo rk on a spatially resolved\, global star-formation history (SFH) of the Sm all Magellanic Cloud (SMC). I use the unprecedented deep photometric data (g~24 magnitude) from the Survey of the MAgellanic Stellar History (SMASH) survey utilising the Dark Energy Camera (DECAm) on the NOAO Blanco 4 m Te lescope. The SFH is quantitatively obtained using colour-magnitude diagram (CMD) fitting techniques. For the first time\, optical depth effects alon g the SMC's line-of-sight are considered in the SFHs derived. \n\nI focus on the SFH of a shell-like structure located in the northeastern part of t he SMC. I compare this SFH to the SFHs of several SMC regions. I discuss t he results of such comparison with a focus on whether the recent and high star formation activity in the shell-like structure is correlated with the enhancements of star formation at young ages in the SMC. Finally\, I put my results in the context of the tidal interactions between the SMC and it s larger companion\, the Large Magellanic Cloud (LMC) to shed light on the origins of the shell-like feature.\n\nhttps://iaus379.aip.de/event/20/con tributions/272/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/272/ END:VEVENT BEGIN:VEVENT SUMMARY:Direct Observations of the Primordial Magellanic Corona DTSTART;VALUE=DATE-TIME:20230323T091200Z DTEND;VALUE=DATE-TIME:20230323T091400Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-271@meetings.aip.de DESCRIPTION:Speakers: Dhanesh Krishnarao (Colorado College)\nRecent measur ements of a high mass for the LMC imply the LMC should host a massive Mage llanic Corona\, a collisionally ionized\, warm-hot gaseous halo at the vir ial temperature $\\sim10^{5.4}$ K initially extending out to the virial ra dius (100 - 130 kpc). Such a primordial Magellanic Corona would have shape d and fed the formation of the Magellanic Stream (e.g. Lucchini et al. 202 0). Now\, we have discovered direct observational evidence for this Magell anic Corona via highly ionized oxygen (O VI)\, and indirect detections via C IV and Si IV\, seen in UV absorption toward background quasars using da ta from HST and FUSE (Krishnarao et al. 2022\, Nature)\, We find the Magel lanic Corona is part of a pervasive multiphase Magellanic CGM seen in many ionization states with a declining projected radial profile out to at lea st 35 kpc from the LMC and a total ionized CGM mass of $10^{(9.1 +/- 0.2)} M_\\odot$. This independently confirms the large mass of the LMC as dynami cally predicted. The evidence for the Magellanic Corona is a crucial step forward in characterizing the Magellanic Group and its nested evolution wi th the Local Group and will help us diagnose the impact of galactic scale winds emerging from star formation feedback in the LMC. In future work fro m an accepted HST Legacy Archival Program (PI: Kat Barger)\, we will direc tly measure and map this galactic scale outflow and the Magellanic Corona using hundreds of sightlines towards stars in the LMC from the ULYSSES pro gram (Roman-Duval et al. 2020).\n\nhttps://iaus379.aip.de/event/20/contrib utions/271/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/271/ END:VEVENT BEGIN:VEVENT SUMMARY:Multiband study of Shell region in the North-Eastern Small Magella nic Cloud using UVIT/AstroSat and Gaia DTSTART;VALUE=DATE-TIME:20230323T091000Z DTEND;VALUE=DATE-TIME:20230323T091200Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-232@meetings.aip.de DESCRIPTION:Speakers: Sipra Hota (Indian Institute of Astrophysics)\nThe S mall Magellanic Cloud (SMC) is one of the nearest\, gas-rich interacting d warf satellites of the Milky Way and the companion of the Large Magellanic Cloud (LMC). The interactions with the LMC and/or with the Milky Way play a significant role in the evolution of the SMC. With its widespread star formation and low metallicity\, the SMC is one of the best test beds to st udy star formation and evolution in a tidally driven environment. The shel l region located in the North-East outskirt of SMC is a tidally affected r egion where there has been recent star formation. Our aim is to understand the spatial distribution\, age dating\, and kinematics of the young popul ation in this part of the tidally affected SMC disk.\nWe obtained far-UV ( FUV) images of eleven fields in the North-East SMC Shell region using the UltraViolet Imaging Telescope (UVIT) on AstroSat. We created science-ready images and performed PSF photometry. We cross-matched the detected FUV st ars with the Gaia EDR3 data and eliminated foreground stars to create an F UV catalog of a few thousand stars. We created FUV-optical color-magnitude diagrams and estimated the ages of the stellar population using isochrone s to map the morphology\, density\, and tidal features of stars younger th an ∼ 600 Myr. The identified episodes of star formation are used to cons train the details of the recent interaction of the SMC with the LMC. We al so estimated the dispersion in the proper motion of the young and old star s to explore the kinematics of the North-East part of the outer SMC disk.\ n\nhttps://iaus379.aip.de/event/20/contributions/232/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/232/ END:VEVENT BEGIN:VEVENT SUMMARY:Centaurus A\, its globular clusters\, planetary nebulae and dark m atter halo shape DTSTART;VALUE=DATE-TIME:20230324T104500Z DTEND;VALUE=DATE-TIME:20230324T110000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-225@meetings.aip.de DESCRIPTION:Speakers: Tadeja Veršič (ESO\, University of Vienna)\nThe ma ss content of the Universe is dominated by non-baryonic dark matter\, acco rding to the Lambda Cold Dark Matter cosmology interpretation of observati onal evidence. However\, not all observations agree with the theory and ma ny predictions remain difficult to investigate. In particular\, simulation s predict that the shapes of the most massive dark matter haloes deviate f rom spherical symmetry. The outer regions of galaxies show the most promin ent signatures of dark matter. Discrete dynamical modeling of halo tracers offers a unique opportunity to further investigate the presence and large -scale distribution of dark matter in galactic haloes. Extended halo popul ations of globular clusters (GCs) and planetary nebulae (PNe) are ideal ki nematic tracers in the outer regions of the galaxies and can be observed o ut to 10 or even 15 effective radii in several galaxies. Using both tracer s that have distinct kinematic properties and spatial distribution helps i n breaking the well-known mass-anisotropy degeneracy that hinders dynamica l modeling. In this work we constrain\, the flattening of the dark matter halo of Centaurs A galaxy (NGC5128). In my talk I will present the analysi s of the photometric and kinematic properties of PNe and GCs and the resul ts from the discrete anisotropic Jeans modeling.\n\nhttps://iaus379.aip.de /event/20/contributions/225/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/225/ END:VEVENT BEGIN:VEVENT SUMMARY:New Satellite Dwarf Galaxies of NGC2683 and M104 and the Search fo r Satellite Planes. DTSTART;VALUE=DATE-TIME:20230324T110000Z DTEND;VALUE=DATE-TIME:20230324T111500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-216@meetings.aip.de DESCRIPTION:Speakers: Ethan Crosby (ANU)\nSince the early 2000s satellite dwarf galaxies of the Local Group and more recently\, the nearby Centaurus A/M83 group\, have been known to show morphological characteristics and s patial distributions that do not match predictions from ΛCDM simulations. In particular\, satellite dwarf galaxies inhabiting the Local Group and t he Centaurus A/M83 group appear to be co-rotating in confined disks known as satellite planes. ΛCDM simulations have failed to fully reproduce sate llite planes despite increasingly advanced simulations\, including baryon physics\, and aren’t associated with galactic analogues of the local uni verse in ΛCDM simulations. Several presented hypotheses suggest that thes e apparent discrepancies may be the result of one of three mechanisms\; th at statistical bias in determinations of satellite planes in the local uni verse leads to inflated significance\, that simulations fail to simulate s ome feature of the universe or that unique conditions in the local univers e led to the formation of satellite planes. This is motivating an internat ional effort to search for satellite galaxies and ultimately\, satellite p lanes\, outside of the local universe. Using the Hyper Suprime Cam from th e Subaru telescope\, we capture ~4 degree field of view images of nearby i solated L* galaxy environments with the intent of identifying satellite dw arf galaxies complete to an absolute g-band magnitude of >-10 and ultimate ly\, identifying satellite planes. These environments reside outside of th e Local Sheet\, which may have provided the conditions that favours the ge neration of satellite planes\, or the galaxies within may not form an inde pendent sample which reduces the significance of satellite planes. Our rec ent research has focused on searching for the satellite galaxies of M104 a nd NGC2683\, two mostly isolated galaxy environments that reside outside o f the local sheet and are thus free from biases associated with it. Across these two environments\, we find over 20 newly discovered highly probably dwarf galaxy candidates up to projected radii of 400 kpc\, which for NGC2 683 are distributed in an anisoptric\, flattened disk and for M104\, a lop -sided but circular disk. We intend to follow up these candidates with obs ervations using IFU-M\, a novel IFU spectroscope undergoing commissioning at the Magellan telescopes of the Las Campanas Observatory in Chile. These spectroscopic observations will confirm that our new galaxy candidates ar e associated with their assumed hosts\, determine if co-rotation is presen t\, and for brighter candidates\, allow us to explore the mass-to-light ra tios and star formation histories of these dwarf galaxies. This spectrosco pically enhanced dataset of newly discovered dwarf satellite galaxies limi ts statistical bias and enables us to answer questions about the local uni verse and our cosmological models\; is the local universe a cosmological o ddity\, or do our models of the universe fail to account for an unknown fa ctor?\n\nhttps://iaus379.aip.de/event/20/contributions/216/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/216/ END:VEVENT BEGIN:VEVENT SUMMARY:Dynamical modelling of cosmologically simulated Dwarf galaxy DTSTART;VALUE=DATE-TIME:20230322T115000Z DTEND;VALUE=DATE-TIME:20230322T115200Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-265@meetings.aip.de DESCRIPTION:Speakers: Amrit Sedain (University of Potsdam)\nProlate rotati on in galaxies (rotation around the major axis) is a rare phenomenon in th e Universe. The effect has been exclusively attributed to past major merge rs and thus studies of prolate-rotating systems can help us better underst and the hierarchical process of galaxy evolution. Dynamical studies of suc h galaxies is important to find their gravitational potential profile\, to tal mass\, and dark matter fraction. Recently\, it has been shown from cos mological simulation that it is possible to form a prolate-rotating dwarf galaxy following a dwarf-dwarf merger event. The simulation also shows tha t the unusual prolate rotation can be time enduring. In this particular ex ample the galaxy started rotating around its major axis about 7.4 Gyr ago and it is still continuing at the present time. In this project\, we use m ock observations of the hydrodynamically simulated galaxy to fit various s tages of its evolution with Jeans dynamical models. The Jeans model succes sfully fits the early oblate state and also for late prolate stage of simu lated galaxy\, prior the major merger event\, recovering the anisotropy\, mass density distribution\, velocity dispersion\, and rotation of the simu lated galaxy. This master thesis project is an important connecting link b etween cosmological simulations and real observational data\, as many prol ate rotation galaxies are being discovered.\n\nhttps://iaus379.aip.de/even t/20/contributions/265/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/265/ END:VEVENT BEGIN:VEVENT SUMMARY:The Formation of Planes of Satellite Galaxies in the Local Group DTSTART;VALUE=DATE-TIME:20230322T114800Z DTEND;VALUE=DATE-TIME:20230322T115000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-263@meetings.aip.de DESCRIPTION:Speakers: Janvi Madhani ()\nNumerous observations in recent ye ars have shown that the satellite galaxies orbiting our local galaxies ten d to align their orbits in one or two thin planes around the host galaxy. This has been observed in local galaxies\, Andromeda and Centaurus A\, and our own Milky Way. Numerical simulations in a cosmological context find t hese planes to be rare or short-lived leading to tension between observati on and theory. This leads to considerable debate on whether observations a re compatible with the standard\, Lambda Cold Dark Matter\, model of cosmo logy. We argue that on large scales\, these simulations did not sufficient ly resolve the nearby large-scale structure\, cosmic filaments\, which we believe to be responsible for the anisotropic infall of satellites forming planar alignments\, and on smaller scales\, they did not sufficiently res olve dwarf satellite galaxies. We use the high precision\, hydrodynamic\, cosmological zoom simulation\, New Horizon\, which has both the large volu me\, (16 Mpc)$^3$ and the small-scale resolution\, ~ 35 pc\, required to s tudy the interplay between cosmic web dynamics and the formation\, funneli ng\, and eventually the anisotropic distribution of satellites around loca l galaxies. Our results indicate that these planes exist in New Horizon in ~ 30% of Milky Way-type systems. The identified planes are comparable to observation in both physical extent and kinematic coherence. We also find that the distribution of dwarf satellites within their host dark matter ha loes is more anisotropic than previously understood.\n\nhttps://iaus379.ai p.de/event/20/contributions/263/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/263/ END:VEVENT BEGIN:VEVENT SUMMARY:The origin of stellar ellipticity in tidally isolated ultra-faint dwarfs DTSTART;VALUE=DATE-TIME:20230322T114600Z DTEND;VALUE=DATE-TIME:20230322T114800Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-257@meetings.aip.de DESCRIPTION:Speakers: Alex Goater (University of Surrey)\nUltra-faint dwar f galaxies (UFDs) are often found in large numbers in close proximity to t he Milky Way and other massive spiral galaxies. As such\, their projected stellar ellipticity and extended light distributions are often thought to owe to tidal forces. I discuss the projected stellar ellipticities and fai nt stellar outskirts of isolated ultra-faints\, drawn from the `Engineerin g Dwarfs at Galaxy Formation’s Edge’ (EDGE) cosmological simulation su ite. I find that\, in spite of their tidal isolation\, the simulated dwarf s exhibit a wide range of projected ellipticities ($0.03 \n\nhttps://iaus3 79.aip.de/event/20/contributions/257/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/257/ END:VEVENT BEGIN:VEVENT SUMMARY:Revealing mass distributions of dwarf spheroidal galaxies in the S ubaru-PFS era DTSTART;VALUE=DATE-TIME:20230322T103000Z DTEND;VALUE=DATE-TIME:20230322T104500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-204@meetings.aip.de DESCRIPTION:Speakers: Kohei Hayashi (NIT\, Ichinoseki college)\nThe dwarf spheroidal galaxies (dSphs) in the Local Group are excellent test beds for probing the properties of dark matter and its role in galaxy formation.\n These galaxies are sufficiently close that it is possible to measure line- of-sight velocities for large samples of resolved stars. This kinematic in formation enables us to study the structural properties of their dark matt er halos.\nHowever\, there are non-negligible uncertainties in the determi nation of the mass profiles of dark matter. \nIn particular\, this study h as been hampered by the well-known degeneracy between dark matter mass den sity and the anisotropy of the stellar velocity dispersion tensor\, which can lead to erroneous mass estimates.\nThe information encoded in the shap e of the line-of-sight velocity distribution (LOSVD) is potentially a stro ng tool to break this degeneracy\, but this requires sufficiently large ki nematic samples over the full radial extent of dSphs and identification of foreground contamination. \nThe combination of the 1.25 deg^2 field and 2394 fibers of the Subaru Prime Focus Spectrograph (PFS)\, plus pre-imagin g with Hyper Suprime Cam\, will allow us to make significant progress in t his undertaking. Furthermore\, the unique capability of PFS will permit us to revisit the core/cusp problem.\nIn this talk\, I will discuss the feas ibility and future prospects for this dark matter study with Subaru-PFS su rvey using mock stellar samples.\n\nhttps://iaus379.aip.de/event/20/contri butions/204/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/204/ END:VEVENT BEGIN:VEVENT SUMMARY:Quenching and ram pressure in simulated low-mass Local Group galax ies DTSTART;VALUE=DATE-TIME:20230322T114400Z DTEND;VALUE=DATE-TIME:20230322T114600Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-262@meetings.aip.de DESCRIPTION:Speakers: Jenna Samuel (UT Austin)\nLow-mass or dwarf galaxies are particularly compelling laboratories for star formation quenching bec ause they are highly susceptible to quenching effects from both internal s tellar feedback and external environment. We explore the role of ram press ure in the environmental regulation of gas content and quenching of low-ma ss galaxies in zoom-in hydrodynamic simulations of Milky Way (MW) mass hos ts. The quiescent fraction of low-mass galaxies increases as their stellar mass decreases and as their distance to a MW-mass host decreases\, simila r to the Local Group. In addition\, the location of a satellite at quenchi ng (in a MW halo\, in a low-mass group\, or in isolation) and the timing o f quenching with respect to different events like infall or pericenter pas sage depend on the mass of the satellite galaxy. In particular\, we find t hat MW satellites can be efficiently quenched before infall into a MW halo by pre-processing in low-mass groups\, where they experience ram pressure comparable to that in a MW halo. Interestingly\, the density of halo gas near paired Local Group-like hosts is enhanced at small angles/latitudes o ff the host galaxy disk versus directly above or below the disk. Prelimina ry results indicate that both observed and simulated satellites within the se low-latitude regions at z=0 may be preferentially quenched\, similar to recently reported anisotropic quenching in massive galaxy clusters at low redshift. In addition\, we briefly discuss morphological changes to low-m ass galaxies induced by the Local Group environment\, such as the formatio n of ultra diffuse galaxies via tidal shocks.\n\nhttps://iaus379.aip.de/ev ent/20/contributions/262/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/262/ END:VEVENT BEGIN:VEVENT SUMMARY:Environmental secular evolution of satellite galaxies DTSTART;VALUE=DATE-TIME:20230322T114200Z DTEND;VALUE=DATE-TIME:20230322T114400Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-259@meetings.aip.de DESCRIPTION:Speakers: Matias Blaña (Instituto of Astrophysics\, Pontifici a Universidad Católica de Chile)\nIn this talk I will present our results on environmental secular evolution processes that affect satellite galaxi es as they enter their hosts. \nOur approaches consist of global statistic al analysis of satellites\, and the modelling of detailed observations. Fo r the latter approach we study distant gas rich dwarf satellites like Leo T and Phoenix\, which are entering the Milky Way. Both satellites present non-equilibrium offsets between their gaseous and stellar distributions\, with Leo T also showing an offset between its younger and older stellar po pulations. Using hydrodynamical simulations that include the Milky Way cor onal wind\, we find that cored dark matter density models can better repro duce the estimated timescales of the offsets in Leo T.\nFrom the global ap proach we present our latest analysis of the Milky Way and the Andromeda s atellite galaxies\, finding a transition radius at R*~0.4-0.6Rvir that del imits an inner satellite population with stellar densities that correlate with the tidal field of their hosts\, and an outer less processed populati on. Furthermore\, we find that this transition radius is also present in s atellites of the Fornax and Virgo galaxy clusters\, as well as in their co smological galaxy simulation counterparts.\n\nhttps://iaus379.aip.de/event /20/contributions/259/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/259/ END:VEVENT BEGIN:VEVENT SUMMARY:Does the presence of old globular clusters in low-mass galaxies di sprove modified gravity? DTSTART;VALUE=DATE-TIME:20230322T114000Z DTEND;VALUE=DATE-TIME:20230322T114200Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-255@meetings.aip.de DESCRIPTION:Speakers: Michal Bilek ()\nThe discussion "dark matter vs. mod ified gravity" has not been resolved yet. It was proposed that dynamical f riction could be used to discriminate between the two alternatives. Analyt ic calculations indicate that\, with modified gravity\, globular clusters (GCs) of low-mass galaxies experience much stronger dynamical friction tha n in the equivalent system with Newtonian gravity and dark matter. As a re sult\, in modified gravity the dynamical friction should have already forc ed the old GCs of low mass galaxies to settle in the centers of the galaxi es. This is not observed. I will report on our efforts to verify the analy tic results by self-consistent simulations with the MOND gravity. We publi shed already that the core stalling mechanism\, that was not considered in the analytic calculations\, prevents GC to settle in centers of ultra-dif fuse galaxies. In our ongoing work\, we investigate GCs of isolated dwarf galaxies. It seems so far that GCs of these galaxies survive if the do not move within the galaxy disk\, or if they counterrotate with respect of th e galaxy disk. In the simulations done so far\, supernova explosions influ ence the orbits of GCs only at low numerical resolution.\n\nhttps://iaus37 9.aip.de/event/20/contributions/255/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/255/ END:VEVENT BEGIN:VEVENT SUMMARY:Kinematical asymmetry in the dwarf irregular galaxy WLM and a pert urbed halo potential DTSTART;VALUE=DATE-TIME:20230322T092900Z DTEND;VALUE=DATE-TIME:20230322T093100Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-256@meetings.aip.de DESCRIPTION:Speakers: Maryam Khademi (IPM \, Institute for Research in Fun damental Sciences (IPM)\, School of Astronomy)\nTo investigate the dynamic al nature of the kinematic asymmetry in the isolated gas-rich dwarf irregu lar galaxy W LM in the Local Group\, we first examine whether an m = 1 per turbation in the halo potential could be a mechanism creating such kinemat ical asymmetry. \nBy fitting a theoretical rotational velocity associated with an m = 1 perturbation in the halo potential model to the observed dat a\, we show that such a lopsided halo potential model can explain the asym metry in the kinematic data reasonably well.\nIn addition\, we study the k inematical classification of the velocity field of WLM with various method s\, and based on a kinemetry analysis\, we find that it is possible for WL M to lie in the transition region\, where the disk and merger coexist. Thu s\, a merger may indeed be one of the possible origins of the dark matter halo lopsidedness for this isolated galaxy.\n\nhttps://iaus379.aip.de/even t/20/contributions/256/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/256/ END:VEVENT BEGIN:VEVENT SUMMARY:Stellar metallicities in the extremely low mass galaxy Leo P DTSTART;VALUE=DATE-TIME:20230322T092700Z DTEND;VALUE=DATE-TIME:20230322T092900Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-236@meetings.aip.de DESCRIPTION:Speakers: Heitor Ernandes (Lund Observatory)\nLeo P is a poorl y studied near-primordial isolated dwarf irregular galaxy at a distance of ∼ 1.6 Mpc\, with an extremely low mass of ∼ 105M⊙.\nFrom Hubble Spa ce Telescope and Arecibo Legacy Fast observations\, its characteristics sh ow the same behaviour as expected in a low-luminosity dSph Milky Way satel lite. It was defined as the “quintessential system to test theories of h ow the smallest structures in our universe survive and grow.”\nObservati ons suggest an ongoing star formation in its prominent H II region. This f eature also gives estimations of the oxygen abundance which is around 3% o f solar. It makes it one of the most metal-poor galaxies known in the loca l Universe.\nIn this work\, we present the first estimated spectroscopic m etallicities of evolved cool stars in Leo P. We use MUSE data to extract a nd analyse the spectra of 16 red giant branch stars. In order to derive th e metallicity of Leo P we apply literature calibrations for our equivalent widths measurements of the Ca II triplet lines.\nWe will also present ten tative luminosity- and stellar mass-metallicity relations compared to othe r low-metallicity galaxies (e.g. I Zw 18\, DDO 68\, and SBS 0335-052W) to check the previously detected offset of these other galaxies\, with respec t to Leo P\, in these relations.\n\nhttps://iaus379.aip.de/event/20/contri butions/236/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/236/ END:VEVENT BEGIN:VEVENT SUMMARY:3D Velocities of Local Group dwarf galaxies combining HST and Gaia DTSTART;VALUE=DATE-TIME:20230322T092500Z DTEND;VALUE=DATE-TIME:20230322T092700Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-224@meetings.aip.de DESCRIPTION:Speakers: Paul Bennet (Space Telescope Science Institute)\nGai a has revolutionized our understanding of the Milky Way (MW) and its satel lite system. However\, the proper motions (PMs) of dwarf galaxies outside the MW system remain out of reach by Gaia and will remain so even with fut ure data releases. This is problematic\, as it means that our understandin g of systems outside the MW will be limited and we may be basing much of o ur cosmological modeling on the MW alone\, which may be atypical. This lim itation can be overcome through the use data from the Hubble Space Telesco pe\, either obtained at two different epochs\, or at one past epoch and co mbined with more recent Gaia positions. I will present new PMs obtained in this manner for a sample of distant dwarf galaxies in the Local Group (LG )\, expanding the number of systems for which we have full position-veloci ty information. These can be used to calculate the implied orbits. I will discuss how this information allows new science with the LG dwarfs and th eir hosts\, linking the star formation and orbital histories of dwarfs to determine when specific dwarfs quenched and whether they are first-infal l or ‘backsplash’ galaxies and how we can use this to determine host p roperties such as halo mass and the extent of the hot gas halo.\n\nhttps:/ /iaus379.aip.de/event/20/contributions/224/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/224/ END:VEVENT BEGIN:VEVENT SUMMARY:Leo T Dissected with the MUSE-Faint Survey DTSTART;VALUE=DATE-TIME:20230322T091000Z DTEND;VALUE=DATE-TIME:20230322T092500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-203@meetings.aip.de DESCRIPTION:Speakers: Daniel Vaz (Instituto de Astrofísica e Ciências do Espaço)\nPrevious studies of Ultra-Faint Dwarfs (UFDs) show that their d ynamical mass-to–light ratios are the highest values measured in any typ e of galaxy\, implying relatively pure dark-matter halos with minimal bary onic content. Furthermore\, UFDs have the lowest metallicities\, oldest ag es\, smallest sizes\, and simplest assembly histories of all galaxies. Und erstanding the nature of these galaxies would improve immensely the knowle dge of the galaxy formation process and help to unravel the nature of dark matter.\n\nThe Leo T UFD is one of the lowest mass galaxies known to cont ain neutral gas and to be also extremely dark-matter dominated. Previous s tudies have shown signs of recent star formation in the galaxy\, making it one of the very faintest galaxies to show this. It is\, therefore\, an in teresting laboratory for studies of gas and star formation at the limit of where galaxies are found to have rejuvenating episodes of star formation. \n\nIn this contribution I will discuss a novel study of Leo T that we hav e done using data from the MUSE integral field spectrograph. The high sens itivity of MUSE allowed us to obtain velocity measurements for stars as fa int as magnitude ~24\, which allowed us to increase the number of Leo T st ars observed spectroscopically from 19 to 75.\nCombining the MUSE data wit h photometric data from HST\, we have studied the age and metallicity of t hese stars and identified two populations\, all consistent with similar me tallicity. Within the young population sample we discovered three emission line Be stars - a first for ultra-faint dwarfs.\nWhile looking for differ ences in the dynamics of young and old stars\, we find that they have diff erent kinematics\, with the young population having a velocity dispersion consistent with the kinematics of the cold component of the neutral gas. \ nIn this contribution I will discuss these results and their implications for the origin and evolution of Leo T.\n\nhttps://iaus379.aip.de/event/20/ contributions/203/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/203/ END:VEVENT BEGIN:VEVENT SUMMARY:High resolution spectroscopy of stars in the outskirts of the Tuca na II ultra-faint dwarf galaxy DTSTART;VALUE=DATE-TIME:20230322T085500Z DTEND;VALUE=DATE-TIME:20230322T091000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-202@meetings.aip.de DESCRIPTION:Speakers: Anirudh Chiti (University of Chicago)\nWe present ki nematics and detailed chemical abundances of stars in the outskirts (out t o ~8 half-light radii) of the Tucana II ultra-faint dwarf galaxy ( 10^7 so lar masses out to 1 kpc). Our results suggest that key factors (e.g.\, mos t metal-poor stars\, evidence of extended halos) in understanding the earl y evolution and dynamical state of these relic galaxies lie in their outsk irts and may have been missed by previous observational work. We demonstra te that detailed spectroscopic studies of individual stars in such low sur face brightness features are now possible.\n\nhttps://iaus379.aip.de/event /20/contributions/202/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/202/ END:VEVENT BEGIN:VEVENT SUMMARY:The Dark Matter Density Profiles of Antlia B DTSTART;VALUE=DATE-TIME:20230322T084000Z DTEND;VALUE=DATE-TIME:20230322T085500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-201@meetings.aip.de DESCRIPTION:Speakers: Mariana P. Júlio (AIP)\nOne particularly promising way to understand the nature of dark matter is to study the so-called core -cusp problem. Many solutions have been investigated to solve it and one p ossibility is that the nature of the dark matter itself is different from the successful $\\Lambda$-Cold Dark Matter model. To reduce the impact of baryonic physics which obscures our ability to constrain dark matter\, we need to study the most dark matter dominated systems known\, ultra-faint d warfs. \nHere we present the first spectroscopic observations of the Antli a B\, a distant (d ∼ 1.35 Mpc) ultra-faint dwarf ($M_V = -9.4$\, M$_\\st ar ∼ 8\\times 10^5$M$_\\odot$ )\, from MUSE-Faint – a survey of ultra- faint dwarfs with the Multi Unit Spectroscopic Explorer. We measure line-o f-sight velocities of 127 member stars\, and combine these with GravSphere \, a Jeans modelling code\, to place constraints on dark matter and derive the first dark matter density profile for this object.\n In particular we present constraints on the nature of self-interacting dark matter (SIDM) that is based on the assumption that the dark matter particles can scatter with one another\, being able to transport heat through the dark matter h alo\, altering the halo structure – and\, possibly\, producing a constan t-density core in the heart of the halo\; and scalar field dark matter (SF DM) that is a Bose-Einstein condensate and a quantum superfluid and can su ppress structure formation when there is a strong repulsive self-interacti on. These are to our knowledge the first constraints on SFDM using ultra-f aint dwarf galaxies and we show that we can rule out SFDM as an explanatio n for the cores in the larger dwarf galaxies in the Local Group. We also s how that if Antlia B has a core produced by SFDM\, the characteristic leng th scale of the repulsive self-interaction has to be smaller than $R_{\\te xt{TF}} \\approx 0.37$ kpc.\n\nhttps://iaus379.aip.de/event/20/contributio ns/201/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/201/ END:VEVENT BEGIN:VEVENT SUMMARY:An aMUSEing view of the dwarf irregular galaxy IC 1613 DTSTART;VALUE=DATE-TIME:20230322T082500Z DTEND;VALUE=DATE-TIME:20230322T084000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-199@meetings.aip.de DESCRIPTION:Speakers: Salvatore Taibi (Leibniz-Institute for Astrophysics Potsdam)\nAnalysing the stellar kinematic properties of a dwarf galaxy mak es it possible to investigate which internal mechanisms have shaped its ev olution. Isolated dwarf galaxies with an extended star formation history\, in particular\, offer the opportunity to study not only star formation pr ocesses at low-mass and low-metallicity scales\, but also to understand ho w internal kinematic properties evolve thanks to the possibility of a comb ined comparison of gas kinematics with that of young and old stars. \n\nIn this context\, we have analysed a new spectroscopic dataset of the isolat ed gas-rich dwarf galaxy IC 1613 taken with the integral-field-unit MUSE i nstrument mounted on the Very Large Telescope (VLT)\, capable of combining high spatial resolution to a wide spectral coverage (4750 − 9300 AA) wi th a resolving power of R = 1500 − 3000. Thanks to this revolutionary in strument\, we obtained a large dataset of ~2000 sources extracted from 3 p ointings\, of which we could reliably perform spectral classification and radial velocity determination for more than 800 stars. We were also able t o obtain metallicities from Ca II triplet lines for a selected subsample o f ~300 red giant branch stars. This dataset is the largest currently colle cted for an isolated dwarf galaxy in the Local Group. \n\nFrom the spectra l classification we found giant stars of all stellar types\, with a large predominance of red giant branch stars\, as to be expected. We were also a ble to identify a sample of C-star candidates\, useful for determining the spectroscopic C/M ratio\, and hot emission line stars as an additional ki nematic tracer for young stars.\nThe preliminary kinematic analysis has le d to a systemic velocity and a velocity dispersion both in agreement with previous literature values. We also found with high statistical significan ce a linear rotation signal along the optical major axis of the galaxy\, w hich is a novelty. Stars follow the velocity field of the neutral HI compo nent\, although they start to decouple from the gas motion around the half -light radius. When subdivided according to age\, young and old stars seem to follow similar kinematic trends\, although the statistics for young st ars drop dramatically in the outermost pointings. \nFinally\, chemical ana lysis resulted in an average [Fe/H] that was slightly higher than literatu re values\, but within the rms dispersion of the stellar luminosity-metall icity relation. We found no evidence of a radial metallicity gradient\, co mpatible with results from other similarly luminous dwarf galaxies.\n\nReg ardless of results actually obtained\, we want to show the vast research p ossibilities that MUSE offers in the field of resolved stellar populations in nearby dwarf galaxies\, whose surface we have only scratched.\n\nhttps ://iaus379.aip.de/event/20/contributions/199/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/199/ END:VEVENT BEGIN:VEVENT SUMMARY:Understanding the formation of the extremely diffuse Andromeda XIX dwarf galaxy DTSTART;VALUE=DATE-TIME:20230322T080000Z DTEND;VALUE=DATE-TIME:20230322T082500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-177@meetings.aip.de DESCRIPTION:Speakers: Michelle Collins (University of Surrey)\nAndromeda ( And) XIX is a unique dwarf galaxy in the M31 system. Its large half-light radius (in excess of 3 kpc) and low surface brightness (29.3 magnitudes pe r square arcsecond) make it one of the most diffuse galaxies in the known Universe. In addition to its extreme structural properties\, its dynamics also suggest that it sits in a low density dark matter halo that may have been shaped by tidal forces. To understand how such a galaxy could form\, we acquired deep HST imaging to resolve stars in this system down to its o ldest main sequence turn-off. These allow us to measure a detailed star fo rmation history for And XIX for the first time. In this talk\, I will pres ent our findings from these data in concert with chemodynamical observatio ns. These will allow me to confront various theories for the formation of And XIX and discuss how such galaxies may form.\n\nhttps://iaus379.aip.de/ event/20/contributions/177/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/177/ END:VEVENT BEGIN:VEVENT SUMMARY:Kinematics of The Tidally Disrupting Dwarf Galaxy Antlia II DTSTART;VALUE=DATE-TIME:20230321T163500Z DTEND;VALUE=DATE-TIME:20230321T165000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-197@meetings.aip.de DESCRIPTION:Speakers: Alexander Ji ()\nThe Milky Way satellite dwarf galax y Antlia II is one of the lowest surface brightness galaxies known. It has a size comparable to the Large Magellanic Cloud\, but only 10^6 solar mas ses of stars. We present kinematic and chemical measurements from the Sout hern Stellar Stream Spectroscopic Survey using the AAT/2dF\, which clearly demonstrate that Antlia II is tidally disrupting. The orbit and velocity gradient also clearly shows that the Milky Way has moved in response to th e Large Magellanic Cloud. However\, Antlia II currently lies on the galaxy mass-metallicity relation\, suggesting that it has not lost too much stel lar mass. These measurements constrain the density profile of Antlia II an d generally illustrate the importance of full dynamic models when interpre ting the masses of local group galaxies.\n\nhttps://iaus379.aip.de/event/2 0/contributions/197/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/197/ END:VEVENT BEGIN:VEVENT SUMMARY:On the many observational challenges to estimating the masses of d warf galaxies DTSTART;VALUE=DATE-TIME:20230321T155500Z DTEND;VALUE=DATE-TIME:20230321T163500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-293@meetings.aip.de DESCRIPTION:Speakers: Alan McConnachie (NRC Herzberg)\nI will briefly summ arise the key methods for the determination of the dynamical mass and mass profiles of dwarf galaxies. I will then discuss in detail the observatio nal challenges associated with making the necessary measurements and obtai ning the necessary data\, with a focus on the systematic\, technical\, and physical limitations of the measurement. I will review the implications o f these limitations for the science we want to do\, and I will summarise f uture prospects for overcoming these challenges.\n\nhttps://iaus379.aip.de /event/20/contributions/293/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/293/ END:VEVENT BEGIN:VEVENT SUMMARY:The Mass of the Local Group DTSTART;VALUE=DATE-TIME:20230321T134500Z DTEND;VALUE=DATE-TIME:20230321T141000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-171@meetings.aip.de DESCRIPTION:Speakers: Wyn Evans (Cambridge University)\nWe review estimate s of the total mass of the Local Group. High-accuracy proper motions (PMs) of M31 and other Local Group (LG) satellites have now been provided by th e Gaia satellite. We revisit the timing argument to compute the total mass of the LG from the orbit of the Milky Way and M31. We discuss a number of systematic effects. The first is caused by the presence of the Large Mage llanic Cloud (LMC). The interaction of the LMC with the Milky Way induces a motion toward the LMC. This contribution to the measured velocity of app roach of the Milky Way and M31 must be removed. The second is the cosmolog ical constant whose effects must be incorporated on these length scales. T he third is to allow for cosmic bias and scatter\, pre-conditioned by the accretion history of the LG. Without taking these into account\, the timin g argument significantly overestimates the true mass. Adjusting for all th ese effects\, we give the estimated mass of the LG for two treatments of M 31's tangential velocity. The first is $M =3.4^{+1.4}_{−1.1} \\times 10^ {12}M_⊙$ (68% CL) when using the M31 tangential velocity $82^{+38}_{−3 5}$ km/s. Lower tangential velocity models with $59^{+42}_{−38}$ km/s ( derived from the same PM data with a flat prior on the tangential velocity ) lead to an estimated mass of $M=3.1^{+1.3}_{−1.0}×10^{12}M_⊙$ (68% CL). By making an inventory of the total mass associated with the four mos t substantial LG members (the Milky Way\, M31\, M33\, and the LMC)\, we es timate the known mass to be in the range $3.7^{+0.5}_{−0.5} \\times 10^ {12}M_⊙$\n\nhttps://iaus379.aip.de/event/20/contributions/171/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/171/ END:VEVENT BEGIN:VEVENT SUMMARY:Large-scale Hydrodynamical Shocks as the Smoking-gun Evidence for a Bar in M31 DTSTART;VALUE=DATE-TIME:20230321T121100Z DTEND;VALUE=DATE-TIME:20230321T121300Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-252@meetings.aip.de DESCRIPTION:Speakers: Zixuan Feng (Shanghai Astronomical Observatory)\nThe formation and evolutionary history of M31 are closely related to its dyna mical structures\, which remain unclear due to its high inclination. Gas k inematics could provide crucial evidence for the existence of a rotating b ar in M31. Using the position–velocity diagram of [O III] and H I\, we a re able to identify clear sharp velocity jump (shock) features with a typi cal amplitude over 100 km/s in the central region of M31 (4.6 kpc × 2.3 k pc\, or 20' x 10'). We also simulate gas morphology and kinematics in barr ed M31 potentials and find that the bar- induced shocks can produce veloci ty jumps similar to those in [O III]. The identified shock features in bot h [O III] and H I are broadly consistent\, and they are found mainly on th e leading sides of the bar/bulge\, following a hallmark pattern expected f rom the bar-driven gas inflow. Shock features on the far side of the disk are clearer than those on the near side\, possibly due to limited data cov erage on the near side\, as well as to obscuration by the warped gas and d ust layers. Further hydrodynamical simulations with more sophisticated phy sics are desired to fully understand the observed gas features and to bett er constrain the parameters of the bar in M31.\n\nhttps://iaus379.aip.de/e vent/20/contributions/252/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/252/ END:VEVENT BEGIN:VEVENT SUMMARY:Detection limits and estimation of Andromeda's mass DTSTART;VALUE=DATE-TIME:20230321T120700Z DTEND;VALUE=DATE-TIME:20230321T120900Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-251@meetings.aip.de DESCRIPTION:Speakers: Amandine Doliva-Dolinsky (Observatoire Astronomique de Strasbourg)\nThe large uncertainties on the measurement of the mass of galaxies is an important issue in modern astrophysics. For both the MW and M31\, thanks to the gas rotation curve\, the mass of the inner part of th e haloes is well constrained. For the outer part of the haloes\, we must t urn to satellites galaxies as tracers. But\, to use dwarf galaxies as such \, it is absolutely crucial to determine the dwarf galaxy detection limits so they can be accurately modeled into the dwarf galaxy system models. I will present the first such effort to characterize fully the dwarf galaxy system of the Andromeda galaxy\, based on the PAndAS photometric mapping. As expected\, the detection limits are a strong function of the size\, lum inosity and the location of a dwarf galaxy in the survey. I will then pres ent the impact of such completeness on the determination of M31 mass.\n\nh ttps://iaus379.aip.de/event/20/contributions/251/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/251/ END:VEVENT BEGIN:VEVENT SUMMARY:Revisiting mass estimates of the Milky Way\, of M31\, and of some spiral galaxies DTSTART;VALUE=DATE-TIME:20230321T120900Z DTEND;VALUE=DATE-TIME:20230321T121100Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-248@meetings.aip.de DESCRIPTION:Speakers: Yongjun JIAO (Paris Observatory)\nWe estimate that t he mass of the Milky Way (MW) is in the range of 2 to 15 $\\times 10^{11} M_\\odot$. It results from an analysis of the rotation curve (RC) from Gai a DR2 and using different profiles for baryon and dark matter (DM\, includ ing NFW & Einasto profile). The lower limit 2 $\\times 10^{11} M_\\odot$ c orresponds to the Keplerian slope of RC at large radii. There were no majo r mergers in the MW since 9 $\\sim$10 Gyr ago and then the dynamical mass is well established from its RC. \n\nHowever\, most distant galaxies have been found in the process of merging\, which perturbs the motion of stars and gas. Thus it is essential to determine if the galaxy outskirts could b e at equilibrium after the merger epoch. Using a library of the simulation s of galaxy major-merger (including M31)\, we will study the criteria for determining the relaxation of galactic disks. We will apply these criteria to the nearby spiral galaxies and determine the relaxation time scale and radius. Then we can measure robust dynamical masses within a given radius .\n\nhttps://iaus379.aip.de/event/20/contributions/248/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/248/ END:VEVENT BEGIN:VEVENT SUMMARY:Exploring the dynamical decoupling of the components of the Androm eda galaxy DTSTART;VALUE=DATE-TIME:20230321T120500Z DTEND;VALUE=DATE-TIME:20230321T120700Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-243@meetings.aip.de DESCRIPTION:Speakers: Jean-Baptiste Salomon (Hebrew University)\nThe study of the dynamical mass of the Local Group requires a detailed knowledge of the velocity of its elements\, in particular of the Milky Way (MW) and th e Andromeda galaxy (M31). Nevertheless\, a discrepancy between the proper motion of the disk of M31 and the global motion of its satellites has been identified. Moreover\, recent results showing the influence of the Magell anic complex on the displacement of the MW disk suggest a possible decoupl ing between the different components of spiral galaxies\, notably the dark and baryonic parts. To explore this possibility\, we study the position a nd kinematic deviations that may arise between the disk of a MW (or M31)-l ike galaxy and its halo\, from constrained high resolution cosmological si mulations of the Local Group in realistic environment\, namely HESTIA simu lations. We focus on the 3-dimensional analysis of the centers of mass (CO M). We present two parts. We first consider individual particles to track down the very nature and amplitude of the physical deviations of the COM w ith respect to the distance from the disk center. Dark matter is dominatin g the behavior of the COM of all particles at all distances. But the total COM is also very close to the COM of stars. In the absence of a significa nt merger\, the velocity offsets are marginal (10 km/s) but the positional shifts can be important compared to the disk characteristics (> 10 kpc). In the event of a major merger\, discrepancies are found to be of the same order as the recent finding for the MW under the Magellanic Clouds influe nce. In a second part\, we put the accent on the study of various populati ons of subhaloes and satellites. We show that while satellites properly re present the entire subhalo population\, there exists strong mismatch in ph ase space between their COM and the host disk. Moreover\, the results are highly inhomogeneous between the simulations\, and thus between the accret ion histories. It is highlighted that these shifts are mainly due to the t hree or four most massive objects. We will finally compare these results i n the light of our observational knowledge.\n\nhttps://iaus379.aip.de/even t/20/contributions/243/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/243/ END:VEVENT BEGIN:VEVENT SUMMARY:Formation of the Andromeda Giant Southern Stream and the ring stru ctures in the Andromeda Galaxy DTSTART;VALUE=DATE-TIME:20230321T112500Z DTEND;VALUE=DATE-TIME:20230321T114000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-189@meetings.aip.de DESCRIPTION:Speakers: Masao Mori (University of Tsukuba)\nRecent observati ons around the M31 have revealed many traces of past interactions with sat ellite galaxies. In particular\, the Andromeda Giant Southern Stream (AGSS ) in the halo and the double ring structure in the disc have been drawing attention. The AGSS is a giant structure extending more than 100 kpc from the center of M31 and is thought to have been formed in a collision with a satellite galaxy about 80 billion years ago (Fardal et al. 2007\; Mori & Rich 2008). On the other hand\, Block et al. (2006) found the double ring structure in M31 made up of gas and dust and argued that the structure was formed by a head-on collision of a satellite galaxy\, M32\, around 20 bil lion years ago. They conclude that the mass of M32 at the time of the coll ision was about one-tenth of the total mass of M31 $\\sim 10^{11} M_\\odot $. Moreover\, a model has been proposed by Hammer et al. (2018) in which t he AGSS and the double ring structure are formed simultaneously by a major merger with the mass of more than $10^{11} M_\\odot$ for the first passag e at the large pericentric distance.\nThese situations motivate us to inve stigate the possible link between the AGSS and the 10kpc ring structures u sing $N$-body/SPH simulations of a miner merger between the M31 and a sate llite galaxy with a mass of $10^{10} M_\\odot$. The simulation result succ essfully matches the observed features of the AGSS and the 10 kpc rings co ncurrently. The stars are smoothly distributed in the galactic disk\, but there are some rings of gas and dust that reproduce the observations. In addition\, we demonstrate the spatial metallicity distribution of the merg er remnants\, assuming the progenitor galaxy's metallicity gradient. The r esult remarkably captures the observed features in the AGSS exhibiting non -uniform metallicity distribution perpendicular to the AGSS axis (Preston et al. 2021). These results indicate that a minor merger of the massive dw arf galaxy is also capable of simultaneously forming the AGSS and the 10 k pc ring.\n\nhttps://iaus379.aip.de/event/20/contributions/189/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/189/ END:VEVENT BEGIN:VEVENT SUMMARY:Probing the mass of the Andromeda galaxy with DESI spectroscopy DTSTART;VALUE=DATE-TIME:20230321T111000Z DTEND;VALUE=DATE-TIME:20230321T112500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-188@meetings.aip.de DESCRIPTION:Speakers: Sergey Koposov (Institute for Astronomy\, University of Edinburgh)\nWe present DESI observations of the stellar halo of M31 wh ich reveal the kinematics of a recent merger in exquisite detail. Using da ta from less than four hours of observations by DESI survey we measure rad ial velocities of more than 7000 sources in M31. These observations show a n intricate coherent kinematic structure in position and velocity space in M31 stellar halo. While hints of coherent structures have been previously detected in M31\, this is the first time they have been seen with such de tail and clarity in a galaxy beyond the Milky Way. We find clear kinematic evidence for multiple shell structures across M31. The kinematics of thes e structures are remarkably similar to the predictions of dynamical models of a single merger event that happened ~2 Gyr ago and enable us to constr ain the gravitational potential of the M31. Using a model of just a small part of the merger debris observed by DESI we estimate the total mass of M 31 within a projected radius of 125 kpc to be log10(M/Msun) = 11.78+/-0.1. This study opens a new era in our ability to map stellar halos and measur e masses of nearby galaxies with high multiplex spectrographs.\n\nhttps:// iaus379.aip.de/event/20/contributions/188/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/188/ END:VEVENT BEGIN:VEVENT SUMMARY:Weighing Andromeda: Mass estimates of the M31 Galaxy DTSTART;VALUE=DATE-TIME:20230321T090500Z DTEND;VALUE=DATE-TIME:20230321T094500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-288@meetings.aip.de DESCRIPTION:Speakers: Souradeep Bhattacharya (Inter University Center for Astronomy and Astrophysics (IUCAA)\, Pune\, India)\nAndromeda (M31) is the nearest giant spiral galaxy to the Milky Way and the most massive member of the Local Group. It has long been recognized that M31's mass measuremen t is essential to understand the formation and evolution of the Local Grou p. I will review the different observational and modelling techniques that have developed over time to measure the mass of M31. I will discuss the t he best constraints today of the M31 mass and the consistency of that obta ined from different techniques. I will also discuss possible improvements on the M31 mass measurement from improved techniques driven by data from f orthcoming instruments and surveys.\n\nhttps://iaus379.aip.de/event/20/con tributions/288/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/288/ END:VEVENT BEGIN:VEVENT SUMMARY:Disrupted vs survived dwarf galaxies in cosmological simulations DTSTART;VALUE=DATE-TIME:20230321T090300Z DTEND;VALUE=DATE-TIME:20230321T090500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-250@meetings.aip.de DESCRIPTION:Speakers: Sergey Khoperskov (AIP)\nSince the chemical abundanc es of stars are the fossil records of the physical conditions in galaxies\ , they provide the key information for recovering the assembly history of galaxies. In this work\, we explore the chemo-chrono-kinematics of accrete d and survived dwarf galaxies by analyzing six M31/MW analogues from the H ESTIA suite of cosmological hydrodynamics zoom-in simulations of the Local Group. We found that accreted stellar haloes\, including individual debri s\, reveal abundance gradients in the E-Lz space\, where the most metal-ri ch stars have formed in the inner parts of the disrupted systems before th e merger and mainly contribute to the central regions of the hosts. Theref ore\, we suggest that abundance measurements in the inner MW will allow to constrain better the parameters of building blocks of the MW stellar halo . We found that the merger debris are chemically distinct from the survive d dwarf galaxies\; however\, the mergers debris have abundances expected f or stars originating from dwarfs that had their star formation activity qu enched at early times. Using the data from the APOGEE spectroscopic survey we also explore some other similarities between satellite galaxies and ac creted stellar halo of the MW.\n\nhttps://iaus379.aip.de/event/20/contribu tions/250/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/250/ END:VEVENT BEGIN:VEVENT SUMMARY:Are the orbital poles of the Milky Way streams pointing to a past Milky Way-Andromeda interaction? DTSTART;VALUE=DATE-TIME:20230321T090100Z DTEND;VALUE=DATE-TIME:20230321T090300Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-246@meetings.aip.de DESCRIPTION:Speakers: Elena Asencio (University of Bonn)\nUnderstanding th e origin of the stellar streams around the Milky Way can be of great relev ance to learn about the history of the Milky Way and the formation of its substructures. A previous study on the Milky Way streams (Pawlowski et al. 2012) showed that many of these (7 out of 14) present a similar orientati on to that of the disk of satellite galaxies (DoS) and the young globular clusters of the Milky Way. This suggests that the DoS\, the young globular clusters and a large fraction of the Milky Way streams have a correlated origin. The authors named this group of subsystems the ``Vast POlar Struct ure" (VPOS)\, and proposed that it could have formed as a result of a past interaction between the Milky Way and the Andromeda galaxy. A more recent study (Riley et al. 2020) analysed 64 Milky Way streams and concluded tha t there is no evidence of clustering around the VPOS direction in the orbi tal poles of the Milky Way streams once the newly discovered streams are t aken into account. In this work\, we revise the distrubution of the orbita l poles of the Milky Way streams in light of the latest stream dataset\, w hich includes a total of 97 streams\, improved measurments of their positi ons and dynamics and a more reliable method for obtaining their orbital po les.\n\nhttps://iaus379.aip.de/event/20/contributions/246/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/246/ END:VEVENT BEGIN:VEVENT SUMMARY:The Milky Way Tomography with Subaru Hyper Suprime-Cam. I. Halo su bstructures DTSTART;VALUE=DATE-TIME:20230321T080000Z DTEND;VALUE=DATE-TIME:20230321T081500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-194@meetings.aip.de DESCRIPTION:Speakers: Yoshihisa Suzuki (Astronomical Institute\, Tohoku Un iversity)\nUnder the current standard scenario\, galaxies such as the Milk y Way (MW) are thought to have formed through repeated mergers and accreti ons of small galaxies due to gravitational interactions. Since the relaxat ion timescale of these traces in phase space is as long as more than 10 bi llion years\, it has been theoretically suggested that they may still exis t in the halo. Advances in large-scale observations have ushered in the er a in which such traces can be investigated observationally. The MW\, to wh ich we belong\, is of particular interest because it is possible to direct ly observe stellar streams and substructures as they are destroyed by tida l forces as small galaxies merge and accrete into it. Currently while the structure and substructures in the halo within 20-30 kpc from the center o f the MW is becoming better understood from the viewpoint of chemodynamics \, the structure in the outer halo is still largely unresolved.\n In this study we used the entire HSC-SSP data (~1400 square degrees)\, characteriz ed by wide field of view (~1.8 square degrees) and deep photometry (i \n\n https://iaus379.aip.de/event/20/contributions/194/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/194/ END:VEVENT BEGIN:VEVENT SUMMARY:The relation between stellar and dark matter haloes of Milky Way-m ass galaxies DTSTART;VALUE=DATE-TIME:20230321T085700Z DTEND;VALUE=DATE-TIME:20230321T085900Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-249@meetings.aip.de DESCRIPTION:Speakers: Anna Genina ()\nIn this talk\, I will discuss the pr edictions of the $\\Lambda$CDM model on the make-up of stellar and dark ma tter haloes of Milky Way-mass galaxies. I will show that the stellar haloe s are made up largely of stars from massive mergers\, like Gaia-Enceladus/ Sausage in the Milky Way\, while the same mergers also make up nearly half of the dark matter halo. Past mergers leave imprints in the phase-space s tructure of the stellar halo. In particular\, the "edge" of the stellar ha lo is defined by the latest major merger and the location of the "edge" is indicative of the total mass and recent assembly history of the galaxy. I will also show that recently accreted massive satellites (analogous to th e LMC) contribute nearly a quarter of the total dark matter mass of Milky Way-mass galaxies despite not being fully disrupted yet.\n\nhttps://iaus37 9.aip.de/event/20/contributions/249/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/249/ END:VEVENT BEGIN:VEVENT SUMMARY:Milky Way Modelling with Stellar Streams DTSTART;VALUE=DATE-TIME:20230321T085900Z DTEND;VALUE=DATE-TIME:20230321T090100Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-244@meetings.aip.de DESCRIPTION:Speakers: Orlin Koop (Kapteyn Astronomical Institute)\nStellar streams are created when globular clusters or dwarf galaxies tidally disr upt in the gravitational potential of their host galaxy. These streams the refore offer a great probe to this galactic potential. Current observation s show a multitude of Milky Way stellar streams to have substructure in th e form of 'spurs'\, 'gaps' and even multiple components. These can origina te from interactions of the stream with dark matter subhalos\, which could probe the nature of dark matter. I'll talk about the specific case of the Jhelum stream\, which shows multiple components after a close interaction with the Sagittarius Dwarf Galaxy\, which means we should take the classi cal satellites into account when modelling stellar streams to infer inform ation about the Milky Way potential. \nAnother recent observation (Dodd et al 2022a) shows that the Helmi Streams seem to orbit near one or multiple resonances. This results in substructure in angular momentum space. To ex plain the persistence of this substructure\, one seems to need a prolate d ark matter halo in the region where the Helmi streams orbit. If there is s ome time left\, I'll talk about this substructure when considered in the c ontext of an alternative theory of gravity called MOND (Modified Newtonian Dynamics). I'll introduce my simple MOND models of the Milky Way and disc uss their ability to sustain this Helmi Streams substructure.\n\nhttps://i aus379.aip.de/event/20/contributions/244/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/244/ END:VEVENT BEGIN:VEVENT SUMMARY:The Milky Way's Rotation Curve Derived from Classical Cepheids DTSTART;VALUE=DATE-TIME:20230321T085500Z DTEND;VALUE=DATE-TIME:20230321T085700Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-231@meetings.aip.de DESCRIPTION:Speakers: Raj Kumar Pradhan (Central Department of Physics\, Tribhuvan University)\nClassical Cepheids are excellent tracers to estimat e the rotation velocity of the galaxies because they provide better distan ce accuracy with less uncertainty. With stringent radial velocity from the recent Gaia DR3 and proper motion\, we estimate the rotation velocity of the Milky Way galaxy for 909 Classical Cepheids. We have used a more accur ate distance estimated based on the period-luminosity from a mid-infrared survey. Up to 20 kpc\, we find the best-fit rotation velocity of 240.15 ± 1.95 km/s (R − R_0) and a concentration parameter of 17.66 ± 0.09. Als o\, we obtain the virial mass of (5.73 ± 0.04 × 10^11)M_0.\n\nhttps://ia us379.aip.de/event/20/contributions/231/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/231/ END:VEVENT BEGIN:VEVENT SUMMARY:Milky Way mass with K giants and BHB stars using LAMOST\, SDSS/SEG UE\, and Gaia: 3D spherical Jeans equation and tracer mass estimator DTSTART;VALUE=DATE-TIME:20230321T083000Z DTEND;VALUE=DATE-TIME:20230321T085500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-173@meetings.aip.de DESCRIPTION:Speakers: Sarah A. Bird ()\nWe measure the enclosed Milky Way mass profile to Galactocentric distances of $\\sim70$ and $\\sim50$ kpc us ing the smooth\, diffuse stellar halo samples of Bird et al. The samples a re LAMOST and SDSS/SEGUE K giants (KG) and SDSS/SEGUE blue horizontal bran ch (BHB) stars with accurate metallicities. The 3D kinematics are availabl e through LAMOST and SDSS/SEGUE distances and radial velocities and {\\it Gaia} DR2 proper motions. Two methods are used to estimate the enclosed ma ss: 3D spherical Jeans equation and Evans et al. tracer mass estimator (TM E). We remove substructure via the Xue et al. method based on integrals of motion. We evaluate the uncertainties on our estimates due to random samp ling noise\, systematic distance errors\, the adopted density profile\, an d non-virialization and non-spherical effects of the halo. The tracer dens ity profile remains a limiting systematic in our mass estimates\, although within these limits we find reasonable agreement across the different sam ples and the methods applied. Out to $\\sim70$ and $\\sim50$ kpc\, the Jea ns method yields total enclosed masses of $4.3\\pm0.95$ (random) $\\pm0.6$ (systematic) $\\times10^{11}$ M$_\\odot$ and $4.1\\pm1.2$ (random) $\\pm0 .6$ (systematic) $\\times10^{11}$ M$_\\odot$ for the KG and BHB stars\, re spectively. For the KG and BHB samples we find a dark matter virial mass o f $M_{200}=0.55^{+0.15}_{-0.11}$ (random) $\\pm0.083$ (systematic) $\\time s10^{12}$ M$_\\odot$ and $M_{200}=1.00^{+0.67}_{-0.33}$ (random) $\\pm0.15 $ (systematic) $\\times10^{12}$ M$_\\odot$\, respectively.\n\nhttps://iaus 379.aip.de/event/20/contributions/173/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/173/ END:VEVENT BEGIN:VEVENT SUMMARY:Scaling up the Milky Way DTSTART;VALUE=DATE-TIME:20230320T154500Z DTEND;VALUE=DATE-TIME:20230320T162500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-289@meetings.aip.de DESCRIPTION:Speakers: Ana Bonaca (Carnegie Observatories)\nOur Galaxy\, th e Milky Way\, provides us with a unique opportunity to measure the 3D shap e of its dark-matter halo\, thus testing the properties of the dark sector and the fundamental cosmological model. Until recently\, however\, these efforts have been thwarted by the scarcity of observational data\, especia lly in the outer halo\, as well as reliance on the assumption of a dynamic al equilibrium\, resulting in estimates of the total Milky Way mass spanni ng a factor of a few. I will discuss how the 6D phase-space data from the Gaia mission and ground-based surveys\, combined with novel modeling metho ds\, have been used to precisely map not just the Milky Way's halo at the present\, but also reconstruct its accretion history.\n\nhttps://iaus379.a ip.de/event/20/contributions/289/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/289/ END:VEVENT BEGIN:VEVENT SUMMARY:DESI and the matter density distribution of the Milky Way from fie ld halo stars DTSTART;VALUE=DATE-TIME:20230320T162500Z DTEND;VALUE=DATE-TIME:20230320T164000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-190@meetings.aip.de DESCRIPTION:Speakers: Monica Valluri (University of Michigan)\nThe Dark En ergy Spectroscopic Instrument (DESI) is currently one of the most powerful instruments for wide-field multi-object spectroscopy. The synergy of DESI with current (e.g. ESA’s Gaia satellite) and future observing facilitie s including the Vera Rubin Observatory’s Legacy Survey of Space and Time (LSST)\, and the Nancy Grace Roman Space Telescope’s High Latitude Surv ey (HLS) will yield datasets of unprecedented size and coverage that will enable strong constraints on the dark matter distribution in the Milky Way (MW) and Local Group galaxies including M31. By the end of 2024 DESI spec tra (350nm-980nm) will be obtained for 7.2 million stars in the main progr am and for up to another 5 million stars via the backup program (bright/po or sky condition) in the MW alone. As of May 2021 (when Kitt Peak shut dow n due to the Conteras Fire) DESI had already obtain spectra of 3.6 million unique stars. After a brief introduction to the DESI MW survey\, its spec troscopic pipeline and what to expect in the early data release (mid 2023) \, I will present results from two new modeling codes that have been recen tly developed to constrain the mass distribution of the MW that utilize th e full 6D as well as 5D phase space data. First I will describe a new B-sp line based non-parametric spherical Jeans modeling code (NIMBLE\, Rehemtul la et al. 2022). Tests of NIMBLE with mock data from the Latte cosmologica l simulations show that it is possible to constraint the mass of the MW ou t to ~80kpc with ~15\\% accuracy even in the presence of halo substructure and moderate amounts of disequilibrium. I will then show preliminary resu lts of the application of NIMBLE to Survey Validation data from DESI. Fina lly\, I will describe results from an axisymmetric distribution function f itting code (Hattori et al. 2021) and results from its application to Gaia RRLyrae data.\n\nhttps://iaus379.aip.de/event/20/contributions/190/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/190/ 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:20241114T092322Z UID:indico-contribution-20-241@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:20241114T092322Z UID:indico-contribution-20-240@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:20241114T092322Z UID:indico-contribution-20-238@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:20241114T092322Z UID:indico-contribution-20-229@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:Forming the Local Group satellite planes in a past Milky Way-Andro meda flyby DTSTART;VALUE=DATE-TIME:20230324T113000Z DTEND;VALUE=DATE-TIME:20230324T114500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-218@meetings.aip.de DESCRIPTION:Speakers: Indranil Banik (University of Saint Andrews)\nThe sa tellite galaxy systems of the Milky Way (MW) and M31 both show a very thin kinematically coherent structure or satellite plane. It has previously be en shown that each plane is in 3.55σ tension with ΛCDM expectations\, wh ich combined with the similar structure around Centaurus A falsifies the m odel at 5.3σ confidence. In this talk\, I will present hydrodynamical sim ulations of the MW and M31 in Milgromian dynamics (MOND)\, which requires them to have experienced a past close flyby roughly 9 Gyr ago. While the f ormation of tidal dwarf galaxies is not resolved\, the tidal debris around each galaxy ends up distributed anisotropically. In each case\, the prefe rred orientation matches that of the actually observed satellite galaxy pl ane (MNRAS\, 513\, 129). The MW and M31 retain thin discs with realistic s cale lengths\, orientations\, and present separation. I will therefore arg ue that the Local Group satellite planes are best understood as arising fr om a past close MW-M31 flyby in MOND\, whose enhancement to gravity at low accelerations naturally explains the apparent dark matter content of the satellite plane members. This contrasts with the Newtonian picture where t idal dwarfs should lack dark matter\, while primordial dwarfs should be di stributed almost isotropically and should moreover constitute the dominant satellite population.\n\nhttps://iaus379.aip.de/event/20/contributions/21 8/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/218/ END:VEVENT BEGIN:VEVENT SUMMARY:Dark matter content and dynamical masses of ultra-diffuse galaxies in the Coma cluster DTSTART;VALUE=DATE-TIME:20230323T134000Z DTEND;VALUE=DATE-TIME:20230323T135500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-217@meetings.aip.de DESCRIPTION:Speakers: Igor Chilingarian (Center for Astrophysics - Harvard and Smithsonian)\nUltra-diffuse galaxies (UDGs) are spatially extended\, low surface brightness stellar systems with regular elliptical-like morpho logy found in a wide range of environments. Studies of the internal dynami cs and dark matter content of UDGs that would elucidate their formation an d evolution have been hampered by their low surface brightnesses. We ident ified a sample of low-mass early-type post-starburst galaxies in the Coma cluster still populated with young stars\, which will passively evolve int o UDGs in the next 5-10 Gyr. We collected deep observations for a large sa mple of low-mass galaxies in the Coma cluster using MMT Binospec. Here\, w e present spatially resolved velocity profiles out to 1 half-light radius\ , stellar velocity dispersions\, ages\, and metallicities for dozens of ol d UDGs in the Coma cluster and the same quantities derived out to 2-3 half -light radii for young dwarf post-starburst galaxies\, the future UDGs. We derived their dynamical masses and dark matter content using Jeans modell ing. High dark matter fractions\, low degrees of rotational support\, mode rately low metallicities place UDGs onto the extension of the dwarf ellipt ical galaxy locus in several galaxy scaling relations such as the Fundamen tal Plane\, the baryonic Tully-Fisher and the mass-metallicity relation. W e demonstrate that statistically at least a half of present-day `old' UDGs were formed by ram-pressure stripping of disky progenitors. We discuss wh ether the same evolutionary scenario is applicable to the entire UDG popul ation.\n\nhttps://iaus379.aip.de/event/20/contributions/217/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/217/ END:VEVENT BEGIN:VEVENT SUMMARY:The Formation of Magellanic System and the total mass of Large Mag ellanic Cloud DTSTART;VALUE=DATE-TIME:20230322T164500Z DTEND;VALUE=DATE-TIME:20230322T170000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-208@meetings.aip.de DESCRIPTION:Speakers: Jianling WANG (National Astronomical Observatories\, Chinese Academy of Sciences)\nThe Magellanic Stream is unique to sample t he MW potential from ~50kpc to 300\nkpc\, and is also unique in constraini ng the LMC mass\, an increasingly important\nquestion for the Local Group/ Milky Way modeling. I will compare on the\nstrengths and weaknesses of th e two types of models (tidal and ram-pressure) of\nthe Magellanic Stream formation. I will present our modeling for the formation\nof the Magellan ic System\, including those of the most recent discoveries in the\nStream\ , in the Bridge and at the outskirts of Magellanic Clouds. This model has\ nbeen successful in predicting most recent observations in both properties of\nstellar and gas phase. It appears that it is an over-constrained mode l and\nprovides a good path to investigate the Stream properties. In part icular\, this\nmodel requires LMC mass significantly smaller than 10^11 Ms un.\n\nhttps://iaus379.aip.de/event/20/contributions/208/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/208/ END:VEVENT BEGIN:VEVENT SUMMARY:Mass models of nearby galaxies from cold gas dynamics DTSTART;VALUE=DATE-TIME:20230324T080000Z DTEND;VALUE=DATE-TIME:20230324T084000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-292@meetings.aip.de DESCRIPTION:Speakers: Federico Lelli (INAF)\nIn this talk I will review te chniques and idiosyncrasies in building mass models of disk galaxies using cold gas dynamics. I will particularly focus on HI disks\, which are gene rally more extended than stellar disks\, so they allow tracing galaxy dyna mics out to the most dark-matter-dominated regions. The combination of HI observations and near-infrared photometry\, tracing the distribution of st ellar mass\, has proven extremely powerful to test both LCDM models of gal axy formation and modified gravity theories such as MOND.\n\nhttps://iaus3 79.aip.de/event/20/contributions/292/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/292/ END:VEVENT BEGIN:VEVENT SUMMARY:Stepping beyond our backyard: the era of Near-Field Cosmology DTSTART;VALUE=DATE-TIME:20230323T130000Z DTEND;VALUE=DATE-TIME:20230323T134000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-291@meetings.aip.de DESCRIPTION:Speakers: Denija Crnojevic (The University of Tampa)\nThe stud y of resolved stellar populations in the nearest galaxies\, or "near-field cosmology"\, provides key constraints on the physics underlying galaxy fo rmation and evolution. In this talk\, I will present an overview of how de ep\, wide-field surveys of nearby groups of galaxies allow us to character ize the past and ongoing accretion processes shaping the halos of Milky Wa y-mass galaxies. This field is set to experience significant advancements with the current and future generations of state-of-the-art telescopes (JW ST\, Roman\, TMT\, VRO).\n\nhttps://iaus379.aip.de/event/20/contributions/ 291/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/291/ 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:20241114T092322Z UID:indico-contribution-20-186@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:20241114T092322Z UID:indico-contribution-20-184@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:Lopsidedness in Andromeda's satellite galaxy distribution: A renew ed tension with CDM simulations DTSTART;VALUE=DATE-TIME:20230322T112500Z DTEND;VALUE=DATE-TIME:20230322T114000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-196@meetings.aip.de DESCRIPTION:Speakers: Kosuke Jamie Kanehisa (Leibniz-Institut für Astroph ysik Potsdam)\nDwarf satellite galaxies around Andromeda (M31) and the Mil ky Way form thin\, coherently rotating planes argued to be in tension with expectations from the cold-dark-matter (CDM) model of cosmology. For M31\ , this disagreement is compounded by a prominent asymmetry in its satellit e distribution\; over 80% of its dwarfs lie in the hemisphere facing the M ilky Way. To a degree\, lopsided dwarf galaxy systems appear to be ubiquit ous in the local Universe and may reflect an underlying asymmetry in their hosts' dark matter halo morphology - in turn carrying implications for ha lo mass estimates derived from satellite dynamics. Adopting a recently pub lished set of homogeneous\, RR Lyrae-based distances to the M31 satellites \, we discovered that the existing asymmetry is strengthened. 34 out of 35 satellites are contained within a cone with an opening angle of 202 degre es (or 213 degrees facing the Milky Way)\, while the luminous dwarf M110 d ominates the nearly hemispheric void on the other side. We further studied the rarity of similarly asymmetric dwarf galaxy distributions in several state-of-the-art cosmological simulations. Even when accounting for the lo ok-elsewhere effect in selecting a preferred opening angle\, less than 0.4 % of M31 analogs host satellite systems that match or exceed the observed asymmetry. The significance of the M31 satellites' observed asymmetry towa rds the Milky Way in CDM simulations now rivals that of M31's plane-of-sat ellites\, cementing the Andromeda system as a striking outlier from cosmol ogical expectations.\n\nhttps://iaus379.aip.de/event/20/contributions/196/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/196/ END:VEVENT BEGIN:VEVENT SUMMARY:Gaia EDR3 proper motions\, energies\, angular momenta of Milky Way dwarfs: a recent infall to the Milky Way halo DTSTART;VALUE=DATE-TIME:20230322T110000Z DTEND;VALUE=DATE-TIME:20230322T112500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-174@meetings.aip.de DESCRIPTION:Speakers: Yanbin Yang (CNRS France / Paris Observatory)\nGaia EDR3 has provided proper motions of Milky Way (MW) dwarf galaxies with an unprecedented accuracy\, which allows us to investigate their orbital prop erties. We found that the total energy and angular momentum of MW dwarfs a re much larger than that of MW K-giant stars\, Sagittarius stream stars an d globular clusters. It suggests that many MW dwarfs have recently infall into the Milky Way halo. We also confirmed that Milky Way dwarfs lie prefe rentially near their pericenters and many of them belong to a vast polar s tructure perpendicular to the Milky Way disk\, which suggests that Milky W ay dwarfs do not behave like satellite systems derived from LCDM cosmologi cal simulations. These new results require revisiting the origin of MW dwa rf galaxies\, e.g.\, if they came recently\, they were likely to have expe rienced gas removal due to the ram pressure induced by MW’s hot gas\, an d to be affected by MW tides. We will discuss the consequences of these pr ocesses on their mass estimation.\n\nhttps://iaus379.aip.de/event/20/contr ibutions/174/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/174/ END:VEVENT BEGIN:VEVENT SUMMARY:Precise constrained cosmological simulations of the Local Group DTSTART;VALUE=DATE-TIME:20230324T111500Z DTEND;VALUE=DATE-TIME:20230324T113000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-221@meetings.aip.de DESCRIPTION:Speakers: Ewoud Wempe (Kapteyn Astronomical Institute)\nCosmol ogical simulations have been used to understand the formation of structure in the LCDM paradigm on small and large scales. Most simulations start wi th unconstrained Gaussian initial conditions\, and therefore generically d o not produce good analogues of the Local Group at present day. While cons trained simulations exist\, these have difficulty in precisely satisfying all our observational constraints on the Local Group\, and their result is not an unbiased and fair sample of the posterior distribution of LCDM uni verses subject to the observational constraints of the Local Group. Some a pplications of such a sample include putting into cosmological context our distribution of satellites\, the alignment of the dark-matter haloes and their spin and the relation to the assembly history\, and to determine the effect of our environment on the Local Group's spatial configuration and kinematics.\n\nIn this work\, we extend the BORG algorithm (Bayesian Origi n Reconstruction from Galaxies)\, that has already been used to model the Local Large-Scale Structure\, to reconstruct the Local Group. Using this t oolset\, we perform a statistical inference on the history of the Local Gr oup\, following a LCDM prior on the cosmological initial conditions\, and a likelihood that constrains local observational quantities\, like the mas ses\, positions\, and velocities of the Milky Way and Andromeda haloes. In the near future\, we plan to embed our Local Group in a realistic large-s cale structure as well. To the best of our knowledge\, this is the first t ime a cosmological simulation has been able to reproduce all these propert ies simultaneously with high precision.\n\nhttps://iaus379.aip.de/event/20 /contributions/221/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/221/ END:VEVENT BEGIN:VEVENT SUMMARY:A dynamical mass map of the nearby Fornax galaxy cluster DTSTART;VALUE=DATE-TIME:20230324T114500Z DTEND;VALUE=DATE-TIME:20230324T120000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-220@meetings.aip.de DESCRIPTION:Speakers: Avinash Chaturvedi (European Southern Observatory)\n The Fornax cluster provides an unparalleled opportunity to investigate the formation and evolution of early-type galaxies in a dense environment. Us ing the spectroscopic data from the Visible Multi-Object Spectrograph at V ery Large Telescope (VLT/VIMOS) from the FVSS survey\, we have kinematical ly characterised the photometrically detected globular cluster (GC) candid ates in the core of the cluster. We confirm a total of 777 GCs new velocit y measurements. Combined with previous literature\, radial velocity measur ements of GCs in Fornax\, we compile the most extensive spectroscopic GC s ample of 2341 objects in this environment.\n\nWith the final goal of under standing the mass assembly of the Fornax galaxy cluster\, we are using our GC radial velocity catalogue to perform dynamical mass modelling of NGC13 99 out to 200 kpc (∼ 6 𝑟𝑒𝑓𝑓 of NGC1399). Using the spherical Jeans modelling\, we have performed the dispersion-kurtosis modelling to obtain the mass profile of NGC1399 and the orbital anisotropy of GCs. We h ave investigated the effect of the intra-cluster GCs in the mass-modelling results.\n\nWe find that both cusp (NFW) and core (Burkert) dark matter ( DM) halo can produce the observed kinematics. Including the intra-cluster GCs in mass-modelling analysis produces a heavier DM halo. Independent of the DM halo profiles used in modelling\, we find that GCs in intra-cluster s have mild radial anisotropy\, especially for the blue GCs. In this talk\ , I will discuss the baryonic and dark matter distribution of the Fornax g alaxy cluster out to half of its virial radius. Specifically\, I will talk about the impact of the intra-cluster GCs on the Fornax cluster mass prof ile. In addition\, I will present the orbital distribution of the intra-cl uster GCs in the Fornax assembly\, showing their accreted nature.\n\nhttps ://iaus379.aip.de/event/20/contributions/220/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/220/ END:VEVENT BEGIN:VEVENT SUMMARY:EDGE: Predicting Scatter in the Stellar Mass–Halo Mass Relation for Dwarf Galaxies DTSTART;VALUE=DATE-TIME:20230324T091000Z DTEND;VALUE=DATE-TIME:20230324T092500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-215@meetings.aip.de DESCRIPTION:Speakers: Stacy Kim (University of Surrey)\nOne of the primary hurdles in pushing dark matter constraints to dwarf scales the uncertaint y in the stellar-mass--halo-mass (SMHM) relation. Results from simulation s differ by two orders of magnitude at halo masses \n\nhttps://iaus379.aip .de/event/20/contributions/215/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/215/ END:VEVENT BEGIN:VEVENT SUMMARY:The oblateness of the dark matter halos of nearby galaxies and its correlation with gas mass fractions DTSTART;VALUE=DATE-TIME:20230324T085500Z DTEND;VALUE=DATE-TIME:20230324T091000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-214@meetings.aip.de DESCRIPTION:Speakers: Mousumi Das (Indian Institute of Astrophysics)\nWe p resent a method to measure the the oblateness parameter q of the dark matt er halo of gas rich galaxies that have extended HI disks. We have applied our model to a sample of 20 nearby galaxies that are gas rich and close to face-on\, of which 6 are large disk galaxies\, 8 have moderate stellar ma sses and 6 are low surface brightness dwarf galaxies. We have used the sta cked HI velocity dispersion and HI surface densities to derive q in the ou ter disk regions. Our most important result is that gas dominated galaxies (such as LSB dwarfs) that have M(gas)/M(baryons)>0.5 have oblate halos (q \n\nhttps://iaus379.aip.de/event/20/contributions/214/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/214/ END:VEVENT BEGIN:VEVENT SUMMARY:On the baryon-driven contraction of dark matter halos DTSTART;VALUE=DATE-TIME:20230324T084000Z DTEND;VALUE=DATE-TIME:20230324T085500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-213@meetings.aip.de DESCRIPTION:Speakers: Pengfei Li (Leibniz-Institute for Astrophysics at Po tsdam)\nThe gravitational interaction between dark matter (DM) and baryons has long been ignored when building galaxies semi-empirically and observa tionally. In this talk\, I will show that the baryonic gravity leads to an adiabatic contraction of DM halos\, ignoring which would result in the bu ilt galaxies that are not in a dynamic equilibrium and hence cannot exist in reality. We propose a new approach to fitting galaxy rotation curves by numerically calculating the contraction of DM halos. We find adiabatic co ntraction makes DM halos more cuspy for massive galaxies\, so that their r otation curves cannot be fit without systematically reducing baryonic cont ributions. We also examine the baryonic effect on the predicted radial acc eleration relation of cold DM model\, and find the predicted relations of massive galaxies are systematically higher than observed. Both tensions po int to a core-cusp problem\, a classical problem for dwarf galaxies but pe rsisting in massive galaxies as well due to strong adiabatic contraction. In order to reconcile this problem\, feedback must work in massive galaxie s as efficiently as in dwarf galaxies.\n\nhttps://iaus379.aip.de/event/20/ contributions/213/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/213/ END:VEVENT BEGIN:VEVENT SUMMARY:The LMC-induced distortion of the Milky Way (and vice versa) DTSTART;VALUE=DATE-TIME:20230323T084000Z DTEND;VALUE=DATE-TIME:20230323T085500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-209@meetings.aip.de DESCRIPTION:Speakers: Michael Petersen (University of Edinburgh)\nThe ongo ing interaction of the Large Magellanic Cloud (LMC) and Milky Way (MW) all ows for constraint of the mass (and profile) of both. Through comparison o f models of the interaction and 6d halo star data\, we determined that the LMC is currently both pulling the MW stellar disc away from the barycentr e of the MW at 30 km/s\, as well as inducing a measurable distortion in th e outer halos of both the MW and LMC. These effects emphasise the need to move away from equilibrium models when attempting to measure the mass dist ributions of either. Models for the M33-M31 interaction -- a similar mass ratio -- reveal a markedly different interaction\, with significantly smal ler effects owing to the orbital history.\n\nhttps://iaus379.aip.de/event/ 20/contributions/209/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/209/ END:VEVENT BEGIN:VEVENT SUMMARY:The OC stream's evolution in the dark matter haloes of the Milky W ay and the LMC DTSTART;VALUE=DATE-TIME:20230323T080000Z DTEND;VALUE=DATE-TIME:20230323T082500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-178@meetings.aip.de DESCRIPTION:Speakers: Denis Erkal (University of Surrey)\nThe OC stream is a dwarf galaxy stream and is one of the longest and best-measured streams in the Galaxy\, spanning over 200 degrees on the sky. It extends from the inner Milky Way ($\\sim$15 kpc) to the outer halo ($\\sim$60 kpc)\, givin g us a great tool with which to measure our Galaxy's dark matter halo. In addition\, portions of the stream pass remarkably close to the LMC ($\\sim $5 kpc)\, allowing us to simultaneously measure the properties of our Gala xy and the LMC. By combining data from Gaia DR3 with the S5 survey\, LAMOS T\, SDSS\, and APOGEE\, I will present a 6D view of the stream. In light o f this powerful data\, we fit the OC stream using a flexible model of the Milky Way halo and the LMC. In particular\, we measure the Milky Way's mas s to a precision of 4% in the middle of the stream's radial extent\, $\\si m$2.85$\\times10^{11}M_\\odot$ at $\\sim$32.4 kpc. We also infer a highly flattened dark matter halo of the Milky Way\, with the data preferring an oblate (q = $\\sim$0.55) and prolate (q = $\\sim$1.40) halo over a spheric al one. Interestingly\, we find that both of these haloes are producing a similar forcefield in the orbital plane of the OC stream\, suggesting they may be attempting to mimic a forcefield which cannot be described with by a flattened halo. We also measure the LMC's dark matter halo. In particul ar\, we find the LMC has a mass of $\\sim1.3\\times10^{11} M_\\odot$\, whi ch is one-sixth the Milky Way's virial mass. Our fits also suggest that th e LMC's dark matter halo must extend out to at least $\\sim$53 kpc from th e LMC\, consistent with the LMC being on first approach to the Milky Way. Finally\, we find that the OC stream's close passage with the LMC occurs $ \\sim$300 Myr ago. Since the OC stream is very sensitive to the LMC's loca tion at this time\, this allows us to better constrain the LMC's past orbi t up to that time. For the first time\, we constrain the amount of dynamic al friction the LMC has experienced and find that it is consistent with wh at is expected given the LMC's substantial dark matter halo. I will end wi th the future directions of this work and how these results can be used to constrain alternative gravity and alternative dark matter models.\n\nhttp s://iaus379.aip.de/event/20/contributions/178/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/178/ END:VEVENT BEGIN:VEVENT SUMMARY:Proper Motions of M31 Satellite Galaxies: M31 Mass\, Satellite Orb its\, and the Dynamical State of the Satellite Plane DTSTART;VALUE=DATE-TIME:20230321T103000Z DTEND;VALUE=DATE-TIME:20230321T105500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-172@meetings.aip.de DESCRIPTION:Speakers: Tony Sohn (Space Telescope Science Institute)\nPrope r motions (PMs) from HST and Gaia have revolutionized the field of Galacti c archaeology in the Milky Way (MW). However\, PM studies in and around ou r neighbor spiral galaxy M31 are still in their early stages with measurem ents being available for only a few satellites and M31 itself at the momen t. Gaia can only detect some of the brightest stars in star forming region s at the distance of M31\, so HST and JWST remain the only reliable option s for measuring PMs of M31 satellite dwarf spheroidals. Three-dimensional kinematics based on PM measurements of satellites will allow constraining the total mass of M31 and testing the dynamical stability of the Great Pla ne of Andromeda. Furthermore\, orbital histories of individual satellites based on the PM results will provide clues to disentangle the processes th at have contributed to the quenching of star formation and help connect so me satellite galaxies to M31 substructures. In this contribution\, I will present the progress of our HST and JWST programs to measure PMs of M31 sa tellite galaxies.\n\nhttps://iaus379.aip.de/event/20/contributions/172/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/172/ 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:20241114T092322Z UID:indico-contribution-20-237@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:20241114T092322Z UID:indico-contribution-20-230@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:20241114T092322Z UID:indico-contribution-20-228@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:20241114T092322Z UID:indico-contribution-20-185@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:20241114T092322Z UID:indico-contribution-20-183@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:20241114T092322Z UID:indico-contribution-20-170@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:20241114T092322Z UID:indico-contribution-20-169@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 BEGIN:VEVENT SUMMARY:Welcome Remarks DTSTART;VALUE=DATE-TIME:20230320T080000Z DTEND;VALUE=DATE-TIME:20230320T081500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-287@meetings.aip.de DESCRIPTION:Speakers: Francois Hammer ()\, Marcel Pawlowski (AIP)\nhttps:/ /iaus379.aip.de/event/20/contributions/287/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/287/ END:VEVENT BEGIN:VEVENT SUMMARY:Closing Remarks DTSTART;VALUE=DATE-TIME:20230324T143000Z DTEND;VALUE=DATE-TIME:20230324T150000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-286@meetings.aip.de DESCRIPTION:Speakers: Francois Hammer ()\, Marcel Pawlowski (AIP)\nhttps:/ /iaus379.aip.de/event/20/contributions/286/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/286/ END:VEVENT BEGIN:VEVENT SUMMARY:Plenary Discussion 5 DTSTART;VALUE=DATE-TIME:20230324T133000Z DTEND;VALUE=DATE-TIME:20230324T143000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-285@meetings.aip.de DESCRIPTION:Speakers: Marina Rejkuba (ESO)\, Stacy McGaugh (Case Western R eserve University)\nhttps://iaus379.aip.de/event/20/contributions/285/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/285/ END:VEVENT BEGIN:VEVENT SUMMARY:Plenary Discussion 4 DTSTART;VALUE=DATE-TIME:20230323T104500Z DTEND;VALUE=DATE-TIME:20230323T114500Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-284@meetings.aip.de DESCRIPTION:Speakers: Maria-Rosa Cioni (Leibniz-Institüt für Astrophysik Potsdam)\, Roeland van der Marel (STScI)\nhttps://iaus379.aip.de/event/20 /contributions/284/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/284/ END:VEVENT BEGIN:VEVENT SUMMARY:Plenary Discussion 3 DTSTART;VALUE=DATE-TIME:20230322T133000Z DTEND;VALUE=DATE-TIME:20230322T143000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-283@meetings.aip.de DESCRIPTION:Speakers: Elena Sacchi (AIP)\, Matthew Walker (Carnegie Mellon University)\nhttps://iaus379.aip.de/event/20/contributions/283/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/283/ END:VEVENT BEGIN:VEVENT SUMMARY:Plenary Discussion 2 DTSTART;VALUE=DATE-TIME:20230321T141000Z DTEND;VALUE=DATE-TIME:20230321T151000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-282@meetings.aip.de DESCRIPTION:Speakers: Beatriz Barbuy (Universidade de Sao Paulo)\, Magda A rnaboldi (ESO)\nhttps://iaus379.aip.de/event/20/contributions/282/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/282/ END:VEVENT BEGIN:VEVENT SUMMARY:Plenary Discussion 1 DTSTART;VALUE=DATE-TIME:20230320T142500Z DTEND;VALUE=DATE-TIME:20230320T150000Z DTSTAMP;VALUE=DATE-TIME:20241114T092322Z UID:indico-contribution-20-281@meetings.aip.de DESCRIPTION:Speakers: Alexander Ji (University of Chicago)\, Roger Ianjama simanana ()\nhttps://iaus379.aip.de/event/20/contributions/281/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/281/ END:VEVENT END:VCALENDAR