Metal Abundances and Depletions in the Neutral Interstellar Medium of Galaxies: the Local Volume as a Laboratory

TL;DR

This study uses high-resolution UV and optical spectroscopy of stars in nearby galaxies to measure metal abundances and depletions, helping to understand chemical enrichment and galaxy evolution.

Contribution

It provides detailed measurements of metal abundances and dust depletion in the neutral interstellar medium of local galaxies, advancing understanding of metal lifecycle in galaxies.

Findings

Quantitative depletion corrections for metals in neutral gas.

Variation of metal abundances across different galaxy types.

Insights into chemical enrichment processes over cosmic time.

Abstract

The comparison of chemical abundances in the neutral gas of galaxies to photospheric abundances of old and young stars, ionized gas abundances, and abundances in galactic halos can trace the chemical enrichment of the universe through cosmic times. In particular, our understanding of chemical enrichment through spectroscopic observations of damped Lyman alpha systems (DLAs) relies on corrections for depletion of metals from the gas to the dust phase. These corrections must be determined in the nearby universe, where both gas-phase abundances and photospheric abundances of young stars recently formed out of the interstellar medium can be measured. Multi-object high-resolution (R>50,000) ultraviolet (970-2400 A) and optical (300-600 nm) spectroscopy toward massive stars in local volume galaxies (D < 15 Mpc) covering a wide range of metallicities (a few % solar to solar) and morphological types will provide the abundance and depletion measurements needed to obtain a detailed and comprehensive characterization of the lifecycle of metals in neutral gas and dust in galaxies, thereby observationally addressing important questions about chemical enrichment and galaxy evolution.