Cosmology at small scales: ultra-light dark matter and baryon cycles in galaxies

The standard model of cosmology has been quite successful in describing how baryonic matter and dark matter cluster by means of gravity, forming the structures we can see today while looking at the sky, and it can reproduce many of the general properties of the observed Universe. However, on the scales of individual galaxies, this model has several complications due to the fact that the true nature of dark matter is still unknown and physical processes involving ordinary matter withing galaxies are not fully understood. By means of computer simulations, I first studied a specific class of dark matter models, called Ultra-Light Dark Matter. I showed that these models better describe some of the properties of dark matter halos, and they develop distinct features which can be tested against astronomical observations. Then, I studied how stars can affect the life cycle of galaxies and dark matter halos. I showed that using a realistic model for supernova explosions can potentially solve the discrepancies between the theoretical predictions of the standard model of cosmology and astronomical observations, reproducing dwarf galaxies and dark matter halos that closely resemble observed ones