Hydrodynamical N-body simulations of galactic coronae in Milky Way-like galaxies

Star-forming galaxies like the Milky Way are surrounded by a hot gaseous atmosphere, the so-called hot corona, that plays a fundamental role in their evolution. The corona is a potential reservoir of fresh, low-metallicity gas that can replenish the disc with new material to sustain the star-formation activity over a Hubble time. Furthermore, galactic fountain flows, ejected from the disc by supernova feedback, interact with the hot coronal gas with major implications for galaxy evolution. This Thesis project is focused on the study of the gas circulation between the disc and the corona of star-forming galaxies like the Milky Way. To analyze this circulation, we used high-resolution hydrodynamical N-body simulations of a Milky Way-type galaxy with the inclusion of an observationally-motivated hot corona around the galaxy. First, we created suitable galaxy models representative of the Milky Way with a hot gaseous halo in hydrostatic equilibrium. After checking the dynamical equilibrium of such configurations with adiabatic simulations, we evolved the initial conditions thus generated with the SMUGGLE model, an explicit ISM and stellar feedback model which is part of the moving-mesh code Arepo. We focused on the interaction between the material ejected from the disc and the galactic corona, analyzing the differences that emerge changing the mass of the latter and studying gas inflows and outflows and their temperature and metallicity distributions. We found that gas accreted from the corona is the primary fuel for the star formation, helping in maintaining a constant level of cold gas mass in the disc of the galaxy. The accretion of coronal gas is promoted by its mixing with the galactic fountains. At the disc-corona interface, the corona and the gaseous outflows from the disc mix efficiently, forming regions of gas at intermediate temperatures and metallicities that enhance the cooling of the corona. This gas is then accreted onto the disc diluting its metallicity.