Wolf-Rayet galaxies - an introduction and a catalog

Abstract

The first catalog of Wolf-Rayet galaxies is presented and discussed. These are a subset of emission-line galaxies in which a broad 4686 He II emission feature due to WR stars is observed in the integrated spectrum. About one-quarter of these galaxies also show a broad line at 4640 A due to N III which is prominent in the latest type WN stars. The number of Lyman-continuum photons emitted by WR galaxies scales roughly with their integrated magnitudes, similar to emission-line galaxies. Both WR galaxies and emission-line galaxies form an overlap with and luminous extension of giant H II regions in these properties. The fraction of WR stars to O stars in some of these galaxies appears to be large, which if confirmed by more detailed quantitative work would imply that the initial mass function was relatively 'flat'.