Warm and hot gas and the evolution of dwarf galaxies

This paper discusses results of multi-wavelength studies of low-mass galaxi es with outflows. As a case study the extreme low-metallicity dwarf galaxy I Zw 18 is presented. The results from HST imaging, long-slit echelle spect roscopy and X-ray imaging are discussed in the context of chemical enrichme nt of dwarf galaxies. If outflows work primarily as a temporary repository of metals and not as a loss of metals into the intergalactic medium, we sho w that galactic winds can explain the relatively low N/O scatter seen in ne arby low-metallicity dwarf galaxies as well as the apparent increase of N/O scatter observed in damped Ly(alpha) systems with metallicities near that of I Zw 18 and below.