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

Abstract

ABSTRACT We investigate the mass–metallicity relation (MZR)for galaxies in the Abell cluster AC114 from 7 h of VIMOS/MR data collected at the European Southern Observatory-Very Large Telescope in 2009. The dynamical analysis completed in our previous paper allowed us to select cluster members, whose spectra are here analysed with stellar population synthesis models. Active and passive galaxies are identified based on the presence/absence of the [O ii] λ3727, [O iii] λλ4959, 5007 and/or Hβ 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 MZR of the cluster is found to be steeper than that for galaxies in the local universe.