BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN 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:20241114T092404Z UID:indico-contribution-57-280@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:20241114T092404Z UID:indico-contribution-57-277@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:20241114T092404Z UID:indico-contribution-57-235@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:20241114T092404Z UID:indico-contribution-57-234@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:20241114T092404Z UID:indico-contribution-57-227@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:20241114T092404Z UID:indico-contribution-57-226@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: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:20241114T092404Z UID:indico-contribution-57-181@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:20241114T092404Z UID:indico-contribution-57-182@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:20241114T092404Z UID:indico-contribution-57-219@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: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:20241114T092404Z UID:indico-contribution-57-225@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:20241114T092404Z UID:indico-contribution-57-216@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: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:20241114T092404Z UID:indico-contribution-57-218@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:20241114T092404Z UID:indico-contribution-57-217@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:Mass models of nearby galaxies from cold gas dynamics DTSTART;VALUE=DATE-TIME:20230324T080000Z DTEND;VALUE=DATE-TIME:20230324T084000Z DTSTAMP;VALUE=DATE-TIME:20241114T092404Z UID:indico-contribution-57-292@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:20241114T092404Z UID:indico-contribution-57-291@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:Precise constrained cosmological simulations of the Local Group DTSTART;VALUE=DATE-TIME:20230324T111500Z DTEND;VALUE=DATE-TIME:20230324T113000Z DTSTAMP;VALUE=DATE-TIME:20241114T092404Z UID:indico-contribution-57-221@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:20241114T092404Z UID:indico-contribution-57-220@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:20241114T092404Z UID:indico-contribution-57-215@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:20241114T092404Z UID:indico-contribution-57-214@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:20241114T092404Z UID:indico-contribution-57-213@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 END:VCALENDAR