Derivation of chemical abundances in star-forming galaxies at intermediate redshift

TL;DR

This study analyzes intermediate-redshift, metal-poor, star-forming galaxies using high-resolution spectra to understand their chemical abundances and the luminosity-metallicity relation, shedding light on galaxy evolution processes.

Contribution

It provides detailed chemical abundance measurements of intermediate-redshift galaxies using high-quality spectra, expanding understanding of galaxy evolution and the luminosity-metallicity relation.

Findings

Oxygen abundances between 7.69 and 8.15, 1/3 to 1/10 of solar

High spectral resolution enables detailed chemical analysis

Diversity among galaxies of similar luminosities observed

Abstract

We have studied a sample of 11 blue, luminous, metal-poor galaxies at redshift 0.744 < z < 0.835 from the DEEP2 redshift survey. They were selected by the presence of the [OIII]4363 auroral line and the [OII]3726,3729 doublet together with the strong emission nebular [OIII] lines in their spectra from a sample of around 6000 galaxies within a narrow redshift range. All the spectra have been taken with DEIMOS, which is a multi-slit, double-beam spectrograph which uses slitmasks to allow the spectra from many objects to be imaged at the same time. The selected objects present high luminosities (20.3 < MB < 18.5), remarkable blue color index, and total oxygen abundances between 7.69 and 8.15 which represent 1/3 to 1/10 of the solar value. The wide spectral coverage (from 6500 to 9100 angstroms) of the DEIMOS spectrograph and its high spectral resolution, R around 5000, bring us an opportunity to study the behaviour of these star-forming galaxies at intermediate redshift with high quality spectra. We put in context our results together with others presented in the literature up to date to try to understand the luminosity-metallicity relation this kind of objects define. The star-forming metal-poor galaxies would be of special relevance in showing the diversity among galaxies of similar luminosities and could serve to understand the processes of galaxy evolution.