The Three Hundred Project: The stellar angular momentum evolution of cluster galaxies

TL;DR

This study uses simulated galaxy clusters to analyze how stellar angular momentum and kinematic properties of galaxies evolve during infall into clusters, finding that most galaxies retain their original stellar kinematics despite environmental stripping.

Contribution

It provides new insights into the resilience of stellar kinematic properties of galaxies during cluster infall, highlighting the limited impact of environmental effects on stellar angular momentum.

Findings

Most galaxies retain their stellar kinematics after infall.

Stellar mergers and close encounters can spin-up galaxies near cluster centers.

Dark matter and gas are stripped, but stellar kinematics remain largely unchanged.

Abstract

Using 324 numerically modelled galaxy clusters as provided by THE THREE HUNDRED project, we study the evolution of the kinematic properties of the stellar component of haloes on first infall. We select objects with M$_{\textrm{star}}>5\times10^{10} h^{-1}M_{\odot}$ within $3R_{200}$ of the main cluster halo at $z=0$ and follow their progenitors. We find that although haloes are stripped of their dark matter and gas after entering the main cluster halo, there is practically no change in their stellar kinematics. For the vast majority of our `galaxies' -- defined as the central stellar component found within the haloes that form our sample -- their kinematic properties, as described by the fraction of ordered rotation, and their position in the specific stellar angular momentum$-$stellar mass plane $j_{\rm star}$ -- M$_{\rm star}$, are mostly unchanged by the influence of the central host cluster. However, for a small number of infalling galaxies, stellar mergers and encounters with remnant stellar cores close to the centre of the main cluster, particularly during pericentre passage, are able to spin-up their stellar component by $z=0$.