The Influence of Environment on the Circumgalactic Medium

TL;DR

This study compares the circumgalactic medium (CGM) in the Virgo Cluster and the field, revealing environment-dependent differences in gas density and covering fraction, which impact galaxy evolution and star formation.

Contribution

It provides the first systematic survey of the CGM in the Virgo Cluster, demonstrating how environment influences CGM properties and galaxy quenching.

Findings

CGM density correlation with impact parameter disappears in Virgo.

Lower CGM covering fraction in the cluster environment.

CGM suppression may lead to star formation quenching.

Abstract

The effect of environment on the circumgalactic medium (CGM) is investigated through a comparison of Lya absorption line data in the Virgo Cluster and the field. This Letter uses the first systematic survey of background QSOs in and around the Virgo Cluster and large existing surveys of galaxies at low redshift. While previous studies found denser gas (higher equivalent width) closer to a galaxy (lower impact parameter), this correlation disappears in the Virgo environment. In addition, the covering fraction of the CGM is lower in the cluster environment than in the circumcluster environment and field. The results indicate that the CGM is suppressed for cluster galaxies while galaxies in the circumcluster environment have abundant CGM. The truncation of the CGM may result in the quenching of star formation through starvation. Our results also show that CGM surveys must consider the role of environment.