The evolution of the mass-metallicity relation at z~3

TL;DR

This study investigates how the relationship between galaxy mass and metallicity evolves at redshift around 3, revealing a stronger evolution than at lower redshifts and challenging some hierarchical galaxy formation models.

Contribution

First measurement of the mass-metallicity relation at z~3.3 using deep near-IR spectroscopy, highlighting significant evolution and potential downsizing effects.

Findings

Mass-metallicity relation at z~3.3 shows strong evolution.

Low mass galaxies exhibit more rapid metallicity evolution.

Results challenge some hierarchical galaxy formation models.

Abstract

We present preliminary results of an ESO-VLT large programme (AMAZE) aimed at determining the evolution of the mass-metallicity relation at z~3 by means of deep near-IR spectroscopy. Gas metallicities and stellar masses are measured for an initial sample of nine star forming galaxies at z~3.3. When compared with previous surveys, the mass-metallicity relation inferred at z~3.3 shows an evolution significantly stronger than observed at lower redshifts. There are also some indications that the metallicity evolution of low mass galaxies is stronger relative to high mass systems, an effect which can be considered as the chemical version of the galaxy downsizing. The mass-metallicity relation observed at z~3.3 is difficult to reconcile with the predictions of some hierarchical evolutionary models. We shortly discuss the possible implications of such discrepancies.