Theoretical Models of the Halo Occupation Distribution: Separating Central and Satellite Galaxies

The halo occupation distribution (HOD) describes the relation between galaxies and dark matter at the level of individual dark matter halos. The properties of galaxies residing at the centers of halos differ from those of satellite galaxies because of differences in their formation histories. Using a smoothed particle hydrodynamics (SPH) simulation and a semi-analytic (SA) galaxy formation model, we examine the separate contributions of central and satellite galaxies to the HOD, more specifically to the probability P(N|M) that a halo of virial mass M contains N galaxies of a particular class. In agreement with earlier results for dark matter subhalos, we find that the mean occupation function <N> for…

• NS
  National Science Foundation

  Award: NAS 5-26555
• NA
  National Aeronautics and Space Administration

  Awards: NAS 5-26555, 5-26555
• OS
  Ohio State University
• ST
  Space Telescope Science Institute

  Awards: NAS 5-26555, 5-26555, 26555