Linking the Metallicity Enrichment History to the Star Formation History: An SFH-regulated Chemical Evolution Model and Its Implications for the Gas Cycling Process

TL;DR

This paper introduces a SFH-regulated chemical evolution model that links a galaxy's star formation history to its metallicity enrichment, successfully reproducing observed data for multiple dwarf galaxies with minimal free parameters.

Contribution

The paper presents a novel SFH-regulated model that directly connects star formation history to metallicity evolution, simplifying the understanding of galaxy chemical enrichment processes.

Findings

Model accurately reproduces MEHs of six dwarf galaxies

Only one free parameter (wind efficiency) needed for all cases

Provides a physically motivated link between SFH and MEH

Abstract

The metallicity enrichment history (MEH) of a galaxy is determined by its star formation history (SFH) and the gas cycling process. In this paper, we construct a chemical evolution model that is regulated by the SFH of the system. In this SFH-regulated model, the evolution of all other variables, including the MEH, can be determined by the SFH. We test this model on six locally isolated dwarf galaxies covering three dwarf types that were observed by the Local Cosmology from Isolated Dwarfs (LCID) project. The SFHs and MEHs of these LCID galaxies have been measured from the deep color-magnitude diagrams that are down to the main sequence turn-offs stars. With simple assumptions of the star formation law and the mass-dependent outflows, our SFH-regulated model successfully reproduces the MEHs of all six LCID galaxies from their SFHs, with only one free parameter, the wind efficiency $\eta \sim 1.0$, for all six galaxies. This model provides a physically motivated link that directly connects the SFH and MEH of a galaxy, which will be useful to accommodate into the state-of-the-art stellar population synthesis models to help relieve the nuisance of the heavy degeneracy between the ages and metallicities of the stellar populations.