The temporal evolution of gas accretion onto the discs of simulated Milky Way-mass galaxies

TL;DR

This study analyzes how gas accretion rates onto Milky Way-like galaxy discs evolve over time using cosmological simulations, highlighting the dynamic nature of inflows and outflows affecting galaxy evolution.

Contribution

It provides a detailed temporal analysis of gas inflow and outflow rates in simulated Milky Way-mass galaxies, revealing their evolution over cosmic time.

Findings

Gas inflow rates vary significantly over time.

Outflow rates are correlated with star formation activity.

Accretion processes influence galaxy morphology and dynamics.

Abstract

In the standard model of structure formation, galaxies form in the centre of dark matter haloes that develop as a result of inhomogeneities in the primordial mass distribution of the Universe. Afterwards, galaxies grow by means of continuous accretion of gaseous material stemming from the intergalactic medium, both in diffuse form and through collisions with other systems. After an initial period of violent growth, the gas settles into a rotationally-supported structure where stars are born, giving birth to the stellar disc. The accretion of gaseous material onto the disc plays a fundamental role in its evolution as it can change its dynamical and morphological properties, generating gas flows within the disc. In this work, we use 30 galaxies from the Auriga Project, a set of cosmological magnetohydrodynamical simulations of disc galaxies, to study the temporal dependence of the gas accretion rates, focusing on the inflowing and outflowing fluxes.