The Massive Star IMF at High Metallicity

Abstract

The question of the variation of the upper IMF at high metallicity is briefly reviewed. I show recent results suggesting a revision in the definition of `high metallicity' in extragalactic H II regions. I present preliminary results concerning constraints on the upper mass limit in metal-rich spiral galaxies derived from the detection of Wolf-Rayet stars in the spectra of their H II regions. The current evidence is in support of an IMF extending up to at least 60-70 solar masses at an oxygen abundance 1-1.5 times the solar value.