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SUMMARY:Dynamical constraints on the galaxy-halo connection - Harry Desmon
 d (Stanford)
DTSTART:20160812T103000Z
DTEND:20160812T113000Z
UID:TALK66722@talks.cam.ac.uk
CONTACT:Martin Haehnelt
DESCRIPTION:While the correlations of galaxy variables are known from surv
 eys\, and the correlations of halo variables from N-body simulations\, the
  relation between galaxy and halo properties -- the galaxy-halo connection
  -- is far from clear. I will describe an ongoing programme aimed at const
 raining this connection using dynamical scaling relations of galaxies\, in
  particular the Tully-Fisher (TFR)\, Faber-Jackson (FJR) and mass discrepa
 ncy-acceleration (MDAR) relations\, and the Fundamental Plane (FP). I deve
 lop an Approximate Bayesian Computation framework to evaluate abundance ma
 tching-based models of the galaxy-halo connection by comparing the predict
 ed and observed values of a number of summary statistics of these relation
 s. I find that while abundance matching naturally accounts for several imp
 ortant statistics (including the slope and normalisation of the TFR\, the 
 tilt of the FP\, and the "acceleration scale" of the MDAR)\, others imply 
 specific constraints on galaxy formation physics: haloes expand in respons
 e to disc formation\, galaxy and halo specific angular momenta are similar
 \, spirals occupy less massive haloes than ellipticals at fixed stellar ma
 ss\, and surface brightness is correlated with halo mass or concentration.
  Several aspects of the relations\, however\, are difficult to accommodate
  within the abundance matching paradigm\; these include the correlation of
  velocity and size residuals in spirals\, and the small scatter of the FP 
 and MDAR. These problems likely indicate correlations of galaxy and halo v
 ariables beyond the scope of current empirical models.
LOCATION:Kavli LMR\, IoA
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