Probing baryonic processes and gastrophysics in the formation of the Milky Way dwarf satellites: I. metallicity distribution properties

TL;DR

This study uses a semi-analytical model to analyze how baryonic processes like supernova feedback and reionization influence the metallicity distribution in Milky Way dwarf satellites, providing insights into galaxy formation.

Contribution

It identifies the sensitivities of metallicity properties to specific baryonic processes and constrains reionization timing and feedback strength using simulated and observational data.

Findings

Metallicity--stellar mass slope sensitive to SN feedback and reionization epoch.

Metal-rich tails mainly influenced by SN feedback.

Metal-poor tails mainly influenced by reionization epoch.

Abstract

In this paper, we study the chemical properties of the stars in the dwarf satellites around the MW-like host galaxies, and explore the possible effects of several baryonic processes, including supernova (SN) feedback, the reionization of the universe and H$_2$ cooling, on them and how current and future observations may put some constraints on these processes. We use a semi-analytical model to generate MW-like galaxies, for which a fiducial model can reproduce the luminosity function and the stellar metallicity--stellar mass correlation of the MW dwarfs. Using the simulated MW-like galaxies, we focus on investigating three metallicity properties of their dwarfs: the stellar metallicity--stellar mass correlation of the dwarf population, and the metal-poor and metal-rich tails of the stellar metallicity distribution in individual dwarfs. We find that (1) the slope of the stellar metallicity--stellar mass correlation is sensitive to the SN feedback strength and the reionization epoch; (2) the extension of the metal-rich tails is mainly sensitive to the SN feedback strength; (3) the extension of the metal-poor tails is mainly sensitive to the reionization epoch; (4) none of the three chemical properties are sensitive to the H$_2$ cooling process; and (5) comparison of our model results with the current observational slope of the stellar metallicity--stellar mass relation suggests that the local universe is reionized earlier than the cosmic average and local sources may have a significant contribution to the reionization in the local region, and an intermediate to strong SN feedback strength is preferred. Future observations of metal-rich and metal-poor tails of stellar metallicity distributions will put further constraints on the SN feedback and the reionization processes.