Cosmological gas accretion of Milky Way-type galaxies and the build-up of galactic discs

Abstract

In this work, we present results on the assembly of stellar discs belonging to Milky Way-type galaxies in the Auriga simulated sample. We study the net accretion of gas onto the disc region as a function of time and radius to assess the feasibility of the so-called inside-out formation of galaxy discs. We found that most of the galaxies in our sample exhibit an inside-out disc growth, with younger stellar populations preferentially formed in the outer regions as accreted material turns into starts. This produces stable discs as long as late-time accretion is free from significant external perturbations.