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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:20241114T092455Z
UID:indico-contribution-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/
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