The Impact of Gas Stripping and Stellar Mass Loss on Satellite Galaxy
  Evolution
  Current semi-analytic models (SAMs) of galaxy formation over-predict the
fraction of passive small late-type satellite galaxies in dense environments by
a factor of two to three. We hypothesize that this is due to inaccurate
prescriptions on cold gas evolution. In the hope of solving this problem we
apply detailed prescriptions on the evolution of diffuse hot gases in
satellites and on stellar mass loss, both of which are critical to model cold
gas evolution. We replace the conventional shock-heating motivated instant
stripping with a realistic gradual prescription based on ram pressure and tidal
stripping. We also carefully consider stellar mass loss in our model. When both
mechanisms are included, the fraction of passive late types matches the data
much more closely. The satellite over-quenching problem is still present in
small galaxies in massive haloes, however. In terms of the detectable residual
star formation rates, gradual diffuse gas stripping appears to be much more
important than stellar mass loss in our model. The implications of these
results and other possibilities, such as redshift-dependent merging geometry
and tidal disruption, are also discussed.
