The nuclear cluster of the milky way: Star formation and velocity dispersion in the central 0.5 parsec

A. Krabbe, R. Genzel, A. Eckart, F. Najarro, D. Lutz, M. Cameron, H. Kroker, L. E. Tacconi-Garman, N. Thatte, L. Weitzel, S. Drapatz, T. Geballe, A. Sternberg, R. Kudritzki

Research output: Contribution to journalArticlepeer-review

Abstract

We report the first results of an extensive new study of the Galactic center stellar cluster. The central parsec is powered by a cluster of about two dozen luminous and helium-rich blue supergiants/Wolf-Rayet stars (Teff i 20,000-30,000 K) with ZAMS masses up to -100 MQ. The most likely scenario for the formation of the massive stars is a small star formation burst between 3 X 106 and 7 X 106 years ago. In this scenario the Galactic center is presently in a short-lived, post-main-sequence “wind phase.” In addition, there is evidence for another star formation event about 108 years ago, as well as for recently formed massive stars that may have been transported into the central core along with orbiting gas streamers. The radial velocity dispersion of 35 early- and late-type stars with distances of 1"-12" from Sgr A* is 154 ± 19 km s-1. Our new results strongly favor the existence of a central dark mass of -3 X 106 M⊙ (density > 108.5 M⊙ pc-3, M/L > 10 M⊙/L⊙) within 0.14 pc of the dynamic center.

Original languageEnglish
Pages (from-to)L95-L99
JournalAstrophysical Journal
Volume447
Issue number2
DOIs
StatePublished - 10 Jul 1995

Keywords

  • Galaxy: center
  • Stars: Wolf-Rayet
  • Stars: formation

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