Galactic winds in dwarf galaxies

Galactic winds are mayor ingredients of our current paradigms of galaxy formation and evolution. They are needed to explain the chemical evolution of galaxies and the intergalactic medium, the luminosity function of galaxies, the formation of galaxies, and the reionization of the universe, just to name a few topics. While the observational support for the presence of galactic winds in massive galaxies and gas-rich mergers is quite strong, the case for galactic winds in dwarf galaxies is much weaker. This is rather surprising, given their shallow potential well and the many examples of star bursts in local dwarf galaxies. Apparently, the physics is complicated in the low-mass case. In this paper we first comment on the theoretical framework for galactic winds in dwarf galaxies and the problems of the observational verification in massive, intermediate mass, and true dwarf galaxies. We then present new observations underlining the complexity of the gas structure of gas halos of dwarf galaxies and the resulting effects on the formation of galactic winds.