The gas discs of galaxies as probes of the baryonic physics of galaxy evolution

The exact nature of the star formation (SF) and feedback (FB) physics driving galaxy evolution remains uncertain. Understanding what shapes the cold gas component, which both provides the fuel for SF and is strongly affected by the subsequent stellar FB, is a crucial step towards a better understanding of the baryon cycle and thus galaxy evolution. I will present detailed analysis of a sample of 60 Milky Way halo-mass galaxies from cosmological simulations. This set of simulations comprises galaxies evolved self-consistently across cosmic time with several different SF and stellar FB models (including early stellar FB). I show that despite broadly similar stellar masses at z=0, other galaxy properties, particularly those of the cold interstellar medium (ISM; e.g. mass, density, morphology) differ significantly between the samples evolved with different baryonic physics. This is a direct consequence of the different models leading to SF in different ISM conditions, thus affecting the impact of the subsequent stellar FB and further evolution of the galaxy. Finally, focussing on the neutral gas, I will demonstrate that the ISM morphology is a particularly promising observable to disentangle the degeneracy between the physics of SF and stellar FB. Comparing the predictions from these simulations with the wealth of observations expected from current and upcoming facilities (e.g. SKA) will significantly advance our understanding of the baryonic physics driving galaxy evolution.