The Dearth of Difference between Central and Satellite Galaxies?

I will introduce our recent works on the difference between central and satellite galaxies. Based on SDSS galaxy and group catalogs, we investigate the star formation activities, AGN activities, size and morphology for both centrals and satellites. We found there is no difference between the two population as long as stellar mass and halo mass are controlled. We compare our results with semi-analytic model and hydrodynamical simulations. We found hydro-simulation can well reproduce our results while SAM fails. We found that environmental processes work in different ways for galaxies below and above a transitional stellar mass. We suggested that the classification based on the transitional stellar mass is more fundamental than the central-satellite dichotomy.