BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN 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:20241114T092402Z UID:indico-contribution-54-191@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:20241114T092402Z UID:indico-contribution-54-180@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:Constraining the Total Mass of M31 with Precision Astrometry DTSTART;VALUE=DATE-TIME:20230321T105500Z DTEND;VALUE=DATE-TIME:20230321T111000Z DTSTAMP;VALUE=DATE-TIME:20241114T092402Z UID:indico-contribution-54-192@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:20241114T092402Z UID:indico-contribution-54-195@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:20241114T092402Z UID:indico-contribution-54-223@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:The Mass of the Local Group DTSTART;VALUE=DATE-TIME:20230321T134500Z DTEND;VALUE=DATE-TIME:20230321T141000Z DTSTAMP;VALUE=DATE-TIME:20241114T092402Z UID:indico-contribution-54-171@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:20241114T092402Z UID:indico-contribution-54-252@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:20241114T092402Z UID:indico-contribution-54-251@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:20241114T092402Z UID:indico-contribution-54-248@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:20241114T092402Z UID:indico-contribution-54-243@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:20241114T092402Z UID:indico-contribution-54-189@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:20241114T092402Z UID:indico-contribution-54-188@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:20241114T092402Z UID:indico-contribution-54-288@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:20241114T092402Z UID:indico-contribution-54-250@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:20241114T092402Z UID:indico-contribution-54-246@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:20241114T092402Z UID:indico-contribution-54-194@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:20241114T092402Z UID:indico-contribution-54-249@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:20241114T092402Z UID:indico-contribution-54-244@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:20241114T092402Z UID:indico-contribution-54-231@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:20241114T092402Z UID:indico-contribution-54-173@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:20241114T092402Z UID:indico-contribution-54-289@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:20241114T092402Z UID:indico-contribution-54-190@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: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:20241114T092402Z UID:indico-contribution-54-172@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 END:VCALENDAR