CLASH-VLT: Is there a dependence in metallicity evolution on galaxy structures?

TL;DR

This study examines how galaxy environment influences metallicity evolution and galaxy structures at z~0.4, finding minimal morphological differences but some variations in the mass-metallicity relation between cluster and field galaxies.

Contribution

It provides new insights into the environmental effects on metallicity and galaxy morphology in clusters at intermediate redshift, using a combined analysis of gas metallicities, SFRs, and structures.

Findings

No significant morphological differences between cluster and field galaxies.

A ~-0.3 dex shift in the MZ relation compared to local SDSS trends.

High mass cluster galaxies often lie below the star-forming main sequence.

Abstract

We investigate the environmental dependence of the mass-metallicty (MZ) relation and it's connection to galaxy stellar structures and morphologies. In our studies, we analyze galaxies in massive clusters at z~0.4 from the CLASH (HST) and CLASH-VLT surveys and measure their gas metallicities, star-formation rates, stellar structures and morphologies. We establish the MZ relation for 90 cluster and 40 field galaxies finding a shift of ~-0.3 dex in comparison to the local trends seen in SDSS for the majority of galaxies with logM<10.5. We do not find significant differences of the distribution of 4 distinct morphological types that we introduce by our classification scheme (smooth, disc-like, peculiar, compact). Some variations between cluster and field galaxies in the MZ relation are visible at the high mass end. However, obvious trends for cluster specific interactions (enhancements or quenching of SFRs) are missing. In particular, galaxies with peculiar stellar structures that hold signs for galaxy interactions, are distributed in a similar way as disc-like galaxies - in SFRs, masses and O/H abundances. We further show that our sample falls around an extrapolation of the star-forming main sequence (the SFR-M* relation) at this redshift, indicating that emission-line selected samples do not have preferentially high star-formation rates (SFRs). However, we find that half of the high mass cluster members (M*>10^10Msun) lie below the main sequence which corresponds to the higher mass objects that reach solar abundances in the MZ diagram.