Environmentally-Driven Evolution of Simulated Cluster Galaxies

TL;DR

This study uses cosmological simulations to analyze how environmental factors like ram-pressure stripping influence gas loss in cluster galaxies, revealing that gas removal is mainly due to gas-only stripping events and occurs over timescales exceeding 1 Gyr.

Contribution

It provides a detailed theoretical analysis of gas loss mechanisms in cluster galaxies, highlighting the dominant role of ram-pressure stripping and the spatial variation of gas accretion.

Findings

Gas loss primarily occurs via gas-only stripping events.

Gas stripping correlates with ram-pressure experienced by galaxies.

Gas removal timescale exceeds 1 Gyr.

Abstract

Galaxies in clusters are gas-deficient and a number of possible explanations for this observation have been advanced, including galaxy-cluster tidal interactions, galaxy harassment, and ISM-ICM gas stripping. In this paper, we use a cosmological simulation of cluster formation and evolution in order to examine this issue from a theoretical standpoint. We follow a large number of galaxies over time and track each galaxy's gas and stellar mass changes to discover what mechanism(s) dominate the evolution of the cluster galaxies. We find that while gas is lost due to a wide variety of mechanisms, the most common way is via a gas-only stripping event, and the amount of gas lost correlates with the ram-pressure the galaxy is experiencing. Although this gas-stripping occurs primarily in the central region (r < 1 Mpc), it is an important mechanism out to the virial radius of the cluster. This is due to the wide scatter in ram-pressure strength that a galaxy experiences at fixed radius. We find that the timescale for complete gas removal is > 1 Gyr. In addition, we find that galaxies in the field and in the cluster periphery (r > 2.4 Mpc) often accrete cool gas; the accretion stops between 1-2.4 Mpc, possibly indicating the onset of galaxy starvation.