The Three Hundred Project: The influence of environment on simulated galaxy properties

TL;DR

This study uses hydrodynamical simulations to explore how galaxy properties like color and star formation rate relate to their environment, revealing that denser regions host redder, more quenched galaxies, consistent with observations.

Contribution

It provides a detailed analysis of environmental effects on galaxy properties using simulated data, highlighting the role of local overdensity in galaxy evolution.

Findings

Galaxies in denser environments are redder and more quenched.

Star formation rate decreases with local overdensity mainly due to higher stellar mass in dense regions.

Color at fixed overdensity is independent of cluster membership, but sample fractions vary with environment.

Abstract

The relationship between galaxy properties and environment is a widely discussed topic within astrophysics. Here we use galaxy samples from hydrodynamical re-simulations to examine this relationship. We use the over-density ($\delta_1$) within a $1 h^{-1}{\rm Mpc}$ sphere around a galaxy to evaluate its environment. Then the relations between galaxy properties, such as specific star formation rate(sSFR), fraction of star forming galaxies, $g-r$ colour and $\delta_1$ are examined within three galactic samples formed from galaxies within large clusters, those in the vicinity of large clusters and those in the field. We find tight environmental correlations for these galaxy properties. In brief, galaxies in denser environments tend to be redder and are more likely to be quenched. This is consistent with observations. We find that although the sSFR decreases with $\delta_1$, this is mainly because that galaxies with higher stellar mass reside in environment with higher overdensity. At fixed over-density a galaxy's color is also independent of whether it lives within a cluster or within the field, but the relative fractions of the two samples varies dramatically with over-density and this drives an apparent evolution.