How does the stellar disk of the Milky Way get its gas?

TL;DR

This study uses cosmological simulations to examine how gas accretion onto the Milky Way's stellar disk varies over time and depends on the galaxy's formation history, supporting the inside-out formation model.

Contribution

It provides a detailed analysis of gas accretion patterns in Milky Way-like galaxies from cosmological simulations, highlighting the influence of assembly history.

Findings

Gas inflows generally decrease with galactocentric distance.

Early high accretion fluxes are consistent with chemical abundance differences.

Accretion behavior varies depending on individual galaxy assembly histories.

Abstract

In chemodynamical evolution models it is usually assumed that the Milky Way galaxy forms from the inside-out implying that gas inflows onto the disk decrease with galactocentric distance. Similarly, to reproduce differences between chemical abundances of the thick disk and bulge with respect to those of the thin disk, higher accretion fluxes at early times are postulated. By using a suite of Milky Way-like galaxies extracted from cosmological simulations, we investigate the accretion of gas on the simulated stellar disks during their whole evolution. In general, we find that the picture outlined above holds, although the detailed behavior depends on the assembly history of the Galaxy and the complexities inherent to the physics of galaxy formation.