The galaxy cluster AC114 -- II. Stellar populations and the mass-metallicity relation

TL;DR

This study examines the relationship between stellar mass and metallicity in galaxies within the galaxy cluster AC114, revealing that active galaxies are less massive and metal-poor, with a steeper mass-metallicity relation than local universe counterparts.

Contribution

It provides the first detailed analysis of the mass-metallicity relation for cluster galaxies at intermediate redshift using spectroscopic data.

Findings

Active galaxies have lower average masses and metallicities.

The mass-metallicity relation in AC114 is steeper than in the local universe.

Spectroscopic analysis distinguishes active and passive galaxy populations.

Abstract

We investigate the mass-metallicity relation for galaxies in the Abell cluster AC114 from 7 hours of VIMOS/MR data collected at the ESO-VLT telescope in 2009. The dynamical analysis completed in our previous paper allowed us to select cluster members, whose spectra are here analyzed with stellar population synthesis models. Active and passive galaxies are identified based on the presence/absence of the [\ion{O}{II}]\lambda3727, [\ion{O}{III}]\lambda\lambda4959,5007 and/or H\beta emission lines, depending on the galaxy redshift. We find that active galaxies have lower average masses than passive ones, and have lower average metallicities. The mass-metallicity relation (MZR) of the cluster is found to be steeper than that for galaxies in the local universe.