Gas-phase metallicity of 27 galaxies at intermediate redshift

TL;DR

This study provides new measurements of gas-phase oxygen abundance for 27 intermediate-redshift galaxies, using emission line ratios from VLT spectra, confirming previous metallicity trends at this epoch.

Contribution

It offers new metallicity data for a sample of galaxies at intermediate redshift, expanding the available measurements with consistent analysis methods.

Findings

Gas-phase oxygen abundances are consistent with previous intermediate-redshift galaxy studies.

Derived metallicity indicators R23 and O32 are presented for the sample.

The results support existing models of galaxy chemical evolution at z~0.4.

Abstract

The purpose of this work is to make available new gas-phase oxygen abundance measurements for a serendipitous sample of 27 galaxies with redshift 0.35<z<0.52. We measured the equivalent widths of the [O II]{\lambda}3727, H{\beta}, and [O III]{\lambda}{\lambda}4959, 5007 emission lines observed in the galaxy spectra obtained with the Visible Multi-Object Spectrograph mounted at the Very Large Telescope. For each galaxy, we derived the metallicity-sensitive emission lines ratio R23, ionization-sensitive emission lines ratio O32, and gas-phase oxygen abundance 12+log(O/H). The values of gas-phase oxygen abundance 12+log(O/H) we obtained for the sample galaxies are consistent with previous findings for galaxies at intermediate redshift.