New chemical evolution analytical solutions including environment effects

TL;DR

This paper derives new analytical solutions for galaxy metallicity evolution considering environmental effects like gas inflow, outflow, and galactic fountains, aiding understanding of high-redshift galaxy observations.

Contribution

It introduces novel analytical models that incorporate environmental effects such as enriched infall and galactic fountains into galaxy chemical evolution analysis.

Findings

Metallicity evolution is similar in closed-box and outflow models under a linear Schmidt law.

Enriched infall shifts the mass-metallicity relation to lower metallicities.

Primordial infall dominates when combined with enriched infall.

Abstract

In the last years, more and more interest has been devoted to analytical solutions, including inflow and outflow, to study the metallicity enrichment in galaxies. In this framework, we assume a star formation rate which follows a linear Schmidt law, and we present new analytical solutions for the evolution of the metallicity (Z) in galaxies. In particular, we take into account environmental effects including primordial and enriched gas infall, outflow, different star formation efficiencies, and galactic fountains. The enriched infall is included to take into account galaxy-galaxy interactions. Our main results can be summarized as: i) when a linear Schmidt law of star formation is assumed, the resulting time evolution of the metallicity Z is the same either for a closed-box model or for an outflow model. ii) The mass-metallicity relation for galaxies which suffer a chemically enriched infall, originating from another evolved galaxy with no pre-enriched gas, is shifted down in parallel at lower Z values, if compared the closed box model. iii) When a galaxy suffers at the same time a primordial infall and a chemically enriched one, the primordial infall always dominates the chemical evolution. iv) We present new solutions for the metallicity evolution in a galaxy which suffers galactic fountains and an enriched infall from another galaxy at the same time. The analytical solutions presented here can be very important to study the metallicity (oxygen), which is measured in high-redshift objects. These solutions can be very useful: a) in the context of cosmological semi-analytical models for galaxy formation and evolution, and b) for the study of compact groups of galaxies.