The Three Hundred project: connection between star formation quenching and dynamical evolution in and around simulated galaxy clusters

TL;DR

This study links star formation quenching in galaxy clusters to dynamical history, showing that most quenched galaxies are ancient infallers affected by ram-pressure stripping, with pre-processing influencing recent infallers and backsplash galaxies.

Contribution

It combines semi-analytic modeling with simulations to analyze how galaxy orbital history impacts star formation quenching in clusters, revealing the dominant role of ram-pressure stripping and pre-processing.

Findings

85% of quenched galaxies are ancient infallers with low gas content.

Quenching often occurs after the first pericentric passage due to ram-pressure stripping.

Pre-processing affects the quenching of recent infallers and backsplash galaxies.

Abstract

In this work, we combine the semi-analytic model of galaxy formation and evolution SAG with the $102$ relaxed simulated galaxy clusters from The Three Hundred project, and we study the link between the quenching of star formation (SF) and the physical processes that galaxies experience through their dynamical history in and around clusters. We classify galaxies in four populations based on their orbital history: recent and ancient infallers, and backsplash and neighbouring galaxies. We find that $\sim 85$ per cent of the current population of quenched galaxies located inside the clusters are ancient infallers with low or null content of hot and cold gas. The fraction of quenched ancient infallers increases strongly between the first and second pericentric passage, due to the removal of hot gas by the action of ram-pressure stripping (RPS). The majority of them quenches after the first pericentric passage, but a non-negligible fraction needs a second passage, specially galaxies with $M_\star \leq 10^{10.5} \, {\rm M_\odot}$. Recent infallers represent $\sim 15$ per cent of the quenched galaxies located inside the cluster and, on average, they contain a high proportion of hot and cold gas; moreover, pre-processing effects are the responsible for quenching the recent infallers prior to infall onto the main cluster progenitor. The $\sim 65$ per cent of quenched galaxies located around clusters are backsplash galaxies, for which the combination of RPS acting during a pre-processing stage and inside the cluster is necessary for the suppression of SF in this population.