An exceptional population of late-type WC stars in the metal-rich spiral galaxy M 83

被引:11
作者
Crowther, PA
Hadfield, LJ
Schild, H
Schmutz, W
机构
[1] Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, S Yorkshire, England
[2] ETH Zentrum, Inst Astron, CH-8092 Zurich, Switzerland
[3] Phys Meteorol Observ, CH-7260 Davos, Switzerland
关键词
galaxies : individual : M 83; stars : Wolf-Rayet;
D O I
10.1051/0004-6361:20040128
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We have surveyed the metal-rich spiral galaxy M 83 (NGC 5236) for its Wolf-Rayet population using VLT-FORS2 narrow-band imaging and follow-up spectroscopy. From a total of 280 candidates identified using He 11 14686 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 similar to1030 is inferred, with N(WC)/N(WN) similar to 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 M 83 with N(WC8-9)/N(WC4-7) = 9 which we attribute to the sensitivity of the classification line C in lambda5696 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 similar to 180 late WC stars and similar to50 late WN stars.
引用
收藏
页码:L17 / L20
页数:4
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