  Although supernova explosions and stellar winds happens at scales bellow 100
pc, they affect the interstellar medium(ISM) and galaxy formation. We use
cosmological N-body+Hydrodynamics simulations of galaxy formation, as well as
simulations of the ISM to study the effect of stellar feedback on galactic
scales. Stellar feedback maintains gas with temperatures above a million
degrees. This gas fills bubbles, super-bubbles and chimneys. Our model of
feedback, in which 10%-30% of the feedback energy is coming from runaway stars,
reproduces this hot gas only if the resolution is better than 50 pc. This is 10
times better than the typical resolution in cosmological simulations of galaxy
formation. Only with this resolution, the effect of stellar feedback in galaxy
formation is resolved without any assumption about sub-resolution physics.
Stellar feedback can regulate the formation of bulges and can shape the inner
parts of the rotation curve.
