Satellite Metallicity Enhancement I: Suppressed Star Formation, Stellar Mass Loss, and Enriched Inflow of DESI and EAGLE Galaxies around Massive Clusters

TL;DR

This study investigates how environmental factors in massive galaxy clusters enhance satellite galaxy metallicities, revealing the roles of gas inflow, star formation suppression, and stellar mass loss through observations and simulations.

Contribution

It introduces a novel chemical evolution model that decomposes satellite metallicity enhancement into physical processes, validated by DESI data and EAGLE simulations.

Findings

Enriched gas inflow dominates the metallicity plateau within the cluster virial radius.

Mass loss and quenching jointly cause rapid metallicity decline in cluster cores.

The observed SME profile is accurately reproduced by the EAGLE simulation.

Abstract

Environmental effects are a primary driver of elevated gas-phase metallicities in galaxies around massive clusters, but the underlying physical mechanisms for this satellite metallicity enhancement (SME) are still unclear. Using the Dark Energy Spectroscopic Instrument (DESI) Data Release 1, we present the first measurement of the average SME as a function of projected cluster-centric distance. The resulting profile reveals three distinct regimes: a steep decline from the cluster center, a plateau near the cluster boundary, and an extended downturn across several cluster radii. Remarkably, the complex shape and amplitude of this observed SME profile are successfully reproduced in the EAGLE cosmological simulation. Drawing insights from EAGLE, we develop a novel satellite chemical evolution model to decompose the observed SME into physical contributions from suppressed star formation, stellar mass loss, and enriched gas inflow. Our analysis shows that continuous accretion of enriched intracluster medium dominates the SME plateau within the cluster virial radius, while mass loss and quenching jointly drive the rapid metallicity decline in the cluster core. Our method disentangles the impacts of three environmental processes on galactic chemical enrichment in the cosmic web, providing a powerful framework for understanding cluster galaxy evolution with current and future spectroscopic surveys.