Strangulation in Galaxy Groups

TL;DR

This study uses cosmological simulations to show that hot gas stripping in galaxy groups can quench star formation by cutting off cold gas supply, leading to galaxy evolution towards S0 types.

Contribution

It demonstrates that hot gas stripping, or strangulation, effectively suppresses star formation in low mass galaxy groups, a process previously less understood.

Findings

Hot gas is stripped over ~1 Gyr, halting cold gas replenishment.

Ram pressure alone is insufficient to remove cold gas in these groups.

Strangulation explains lower star formation rates in group galaxies.

Abstract

We use a cosmological chemodynamical simulation to study how the group environment impacts the star formation properties of disk galaxies. The simulated group has a total mass of M~8x10^12 Msun and a total X-ray luminosity of L_X~10^41 erg s^-1. Our simulation suggests that ram pressure is not sufficient in this group to remove the cold disk gas from a V_rot~150 km s^-1 galaxy. However, the majority of the hot gas in the galaxy is stripped over a timescale of approximately 1 Gyr. Since the cooling of the hot gas component provides a source for new cold gas, the stripping of the hot component effectively cuts off the supply of cold gas. This in turn leads to a quenching of star formation. The galaxy maintains the disk component after the cold gas is consumed, which may lead to a galaxy similar to an S0. Our self-consistent simulation suggests that this strangulation mechanism works even in low mass groups, providing an explanation for the lower star formation rates in group galaxies relative to galaxies in the field.