  Using the SDSS DR4 group catalogue of Yang et al. (2007), we investigate
sizes, concentrations, colour gradients and surface brightness profiles of
central and satellite galaxies. We compare central and satellite galaxies at
fixed stellar mass, in order to disentangle environmental from stellar mass
dependencies. Early and late type galaxies are defined according to
concentration. We find that at fixed stellar mass, late type satellite galaxies
have smaller radii and larger concentrations than late type central galaxies.
No such differences are found for early-type galaxies. We have also constructed
surface brightness and colour profiles for the central and satellite galaxies
in our sample. We find that late-type satellite galaxies have a lower surface
brightness and redder colours than late-type central galaxies. We show that all
observed differences between satellite and central galaxies can be explained by
a simple fading model, in which the star formation in the disk decreases over
timescales of 2-3 Gyr after a galaxy becomes a satellite. Processes that induce
strong morphological changes (e.g. harassment) and processes that strip the
galaxy of its entire ISM need not to be invoked in order to explain the
environmental dependencies we find.
