Gas depletion in cluster galaxies depends strongly on their internal structure

TL;DR

This study shows that in galaxy clusters, a galaxy's internal structure, especially its stellar density, strongly influences how much gas it loses, with lower density galaxies being more depleted regardless of their mass or cluster location.

Contribution

It introduces a photometric gas mass indicator to analyze gas depletion and reveals that stellar surface density is a key factor in gas loss in cluster galaxies.

Findings

Lower density galaxies are more gas-depleted than higher density ones.

Gas depletion depends more on stellar surface density than on stellar mass.

No clear trend between cluster velocity dispersion and gas depletion.

Abstract

We analyze galaxies in 300 nearby groups and clusters identified in the Sloan Digital Sky Survey using a photometric gas mass indicator that is useful for estimating the degree to which the interstellar medium of a cluster galaxy has been depleted. We study the radial dependence of inferred gas mass fractions for galaxies of different stellar masses and stellar surface densities. At fixed clustercentric distance and at fixed stellar mass, lower density galaxies are more strongly depleted of their gas than higher density galaxies. An analysis of depletion trends in the two-dimensional plane of stellar mass $M_*$ and stellar mass surface density $\mu_*$ reveals that gas depletion at fixed clustercentric radius is much more sensitive to the density of a galaxy than to its mass. We suggest that low density galaxies are more easily depleted of their gas, because they are more easily affected by ram-pressure and/or tidal forces. We also look at the dependence of our gas fraction/radius relations on the velocity dispersion of the cluster, finding no clear systematic trend.