The impact of stellar feedback on galaxies

Small-scale stellar feedback can impact the large-scale evolution of galaxies by regulating star formation and by driving galactic fountain flows and outflows. Using modern high-performance computing simulations, we can study the relative importance of stellar winds, radiation, and supernovae in shaping the multi-phase interstellar medium. Using these simulations, we find that pre-supernova feedback is highly relevant for regulating star formation. In particular, the ionizing radiation of massive stars is dominating over the impact of non-ionizing radiation or stellar winds. On the other hand, supernovae drive hot bubbles and super-bubbles with substantially higher pressure than the typical midplane pressure of a disk galaxy, thereby pushing gas out into the circum-galactic medium. Additionally, cosmic rays, which are in this context most importantly accelerated by supernova shocks, help to sustain the galactic outflow via a vertical cosmic ray pressure gradient.