The Impact of Gas Stripping and Stellar Mass Loss on Satellite Galaxy Evolution

TL;DR

This paper improves galaxy formation models by implementing more realistic gas stripping and stellar mass loss processes, leading to better agreement with observed satellite galaxy properties.

Contribution

It introduces a gradual ram pressure and tidal stripping model and detailed stellar mass loss prescriptions, enhancing the accuracy of satellite galaxy evolution simulations.

Findings

Gradual gas stripping aligns model predictions with observed passive galaxy fractions.

Stellar mass loss has a lesser impact compared to diffuse gas stripping.

Residual star formation is mainly influenced by gas stripping processes.

Abstract

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.