Investigating the Projected Phase Space of Gaussian and Non-Gaussian Clusters

TL;DR

This study examines how galaxy properties and cluster environments differ between Gaussian and non-Gaussian clusters using projected phase-space analysis, revealing differences in mass accretion, galaxy ages, and metallicity.

Contribution

It introduces a comparative analysis of Gaussian and non-Gaussian galaxy clusters based on phase-space distributions and infall histories, highlighting environmental impacts on galaxy evolution.

Findings

NG clusters are more massive and less concentrated than G clusters.

NG clusters have an excess of faint galaxies and higher recent stellar mass accretion.

Galaxy properties and infall times differ significantly between G and NG clusters.

Abstract

By way of the projected phase-space (PPS), we investigate the relation between galaxy properties and cluster environment in a subsample of groups from the Yang Catalog. The sample is split according to the gaussianity of the velocity distribution in the group into gaussian (G) and non-gaussian (NG). Our sample is limited to massive clusters with $\rm M_{200} \geq 10^{14} M_{\odot}$ and $\rm 0.03\leq z \leq 0.1$. NG clusters are more massive, less concentrated and have an excess of faint galaxies compared to G clusters. NG clusters show mixed distributions of galaxy properties in the PPS compared to the G case. Using the relation between infall time and locus on the PPS, we find that, on average, NG clusters accreted $\rm \sim 10^{11}\,M_{\odot}$ more stellar mass in the last $\sim 5$ Gyr than G clusters. The relation between galaxy properties and infall time is significantly different for galaxies in G and NG systems. The more mixed distribution in the PPS of NG clusters translates into shallower relations with infall time. Faint galaxies whose first crossing of the cluster virial radius happened 2-4 Gyr ago in NG clusters are older and more metal-rich than in G systems. All these results suggest that NG clusters experience a higher accretion of pre-processed galaxies, which characterizes G and NG clusters as different environments to study galaxy evolution.