Wolf-Rayet stars in starburst galaxies

Wolf-Rayet stars have been detected in a large number of galaxies experienc ing intense bursts of star formation. All stars initially more massive than a certain, metallicity-dependent, value are believed to experience the Wol f-Rayet phase at the end of their evolution, just before collapsing in supe rnova explosion. The detection of Wolf-Rayet stars puts, therefore, importa nt constraints on the evolutionary status of starbursts, the properties of their Initial Mass Functions and their star formation regime. In this contr ibution we review the properties of galaxies hosting Wolf-Rayet stars, with special emphasis on the factors that determine their presence and evolutio n, as well as their impact on the surrounding medium. (C) 2000 Elsevier Sci ence B.V. All rights reserved.