Alexis FINOGUENOV
(MPE/UMBC)
X-ray catalog of galaxy groups in COSMOS has reached the high-level, having complete identification at z<1.2 and weak lensing mass calibration at z<1.2. A number of statistical tests have been developed to probe the galaxy evolution using the knowledge of halo mass available for this sample. Of particular success is the direct calculation of the halo occupation statistics for galaxies of various type. I will review the current progress on this analysis and conclude on what drives some of the galaxy appearance in the groups.