An exceptional population of late-type WC stars in the metal-rich spiral galaxy

Abstract

We have surveyed the metal-rich spiral galaxy M83 (NGC5236) for its Wolf-Rayet population using VLT-FORS2 narrow-band imaging and follow-up spectroscopy. From a total of 280 candidates identified using HeII 4686 imaging, Multi Object Spectroscopy of 198 sources was carried out, revealing 132 objects containing bona-fide Wolf-Rayet features. From this sample, an exceptional W-R content of 1030 is inferred, with N(WC)/N(WN)=1.3, continuing the trend to larger values at higher metallicity amongst Local Group galaxies. More dramatic is the dominance of late-type WC stars in M83 with N(WC8-9)/N(WC4-7)=9 which we attribute to the sensitivity of the classification line CIII 5696 to mass-loss, providing the strength of WC winds scale with metallicity. One young massive compact cluster, #74 in our catalogue, hosts 20% of the entire galactic population, namely 180 late WC stars and 50 late WN stars.

arXiv comment4 pages, 2 figures, revised manuscript, accepted by A&A Letters

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• A Spectroscopic Search for the non-nuclear Wolf-Rayet Population of the metal-rich spiral galaxy M83
• Do Wolf-Rayet stars have similar locations in hosts as type Ib/c supernovae and long gamma-ray bursts?
• Chemical abundances in Seyfert galaxies -IX. Helium abundance estimates
• Physical Properties of Young Stellar Populations in 24 Starburst Galaxies Observed with FUSE
• The Young Outer Disk of M83