  We investigate the generation of galactic outflows by supernova feedback in
the context of SPH cosmological simulations. We use a modified version of the
code GADGET-2 which includes chemical enrichment and energy feedback by
Supernova. We find that energy feedback plays a fundamental role in the
evolution of galaxies, heating up the cold material in the centre of the haloes
and triggering outflows which efficiently transport gas from the centre to the
outskirts of galaxies. The impact of feedback is found to depend on the virial
mass of the system with smaller systems, such as dwarf galaxies, being more
strongly affected. The outflows help to establish a self-regulated star
formation process, and to transport a significant amount of metals into the
haloes and even out of the systems. According to our results, energy feedback
by supernovae could be the mechanism responsible for the chemical enrichment of
the intergalactic medium.
