On the scatter of the present-day stellar metallicity-mass relation of cluster dwarf galaxies

TL;DR

This study investigates the variability in the stellar metallicity-mass relation of cluster dwarf galaxies using the Illustris simulation, highlighting the role of stellar mass stripping and metallicity enrichment processes.

Contribution

It reveals that stellar mass stripping influences the scatter in the metallicity-mass relation and links metallicity increases to stripping of low-metallicity stars in galaxy outskirts.

Findings

Smallest scatter at peak stellar mass

Mass stripping broadens the metallicity-mass relation

Mass stripping can increase stellar metallicity in some galaxies

Abstract

We examine the scatter of the relation between stellar mass and stellar metallicity for cluster dwarf galaxies in the cosmological simulation Illustris. The mass-metallicity relation exhibits the smallest intrinsic scatter at the galaxies' times of peak stellar mass, suggesting stellar mass stripping to be the primary effect responsible for the rather broad relation at present. However, for about 40% of galaxies in the high-metallicity tail of the relation, we find mass stripping to coincide with an increased enrichment of stellar metallicity, possibly caused by the stripping of low-metallicity stars in the galaxy outskirts.