Galaxy Groups in the SDSS DR4: II. halo occupation statistics

Understand

We investigate various halo occupation statistics using a large galaxy group catalogue constructed from the SDSS DR4 with an adaptive halo-based group finder.

• The conditional luminosity function (CLF) is measured separately for all, red and blue galaxies, as well as in terms of central and satellite galaxies.
• The CLFs for central and satellite galaxies can be well modelled with a log-normal distribution and a modified Schechter form, respectively.
• About 85% of the central galaxies and about 80% of the satellite galaxies in halos with masses $M_h\ga 10^{14}\msunh$ are red galaxies.