Adding Environmental Gas Physics to the Semi-Analytic Method for Galaxy Formation: Gravitational Heating

Understand

We present results of an attempt to include more detailed gas physics motivated from hydrodynamical simulations within semi-analytic models (SAM) of galaxy formation, focusing on the role that environmental effects play.

• The main difference to previous SAMs is that we include 'gravitational' heating of the intra-cluster medium (ICM) by the net surplus of gravitational potential energy released from gas that has been stripped from infalling satellites.
• Gravitational heating appears to be an efficient heating source able to prevent cooling in environments corresponding to dark matter halos more massive than $\sim 10^{13} $M$_{\odot}$.
• The energy release by gravitational heating can match that by AGN-feedback in massive galaxies and can exceed it in the most massive ones.