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The Nuclear Star Cluster of the Milky Way: Star Formation, Stellar Collisions and Central Dark Mass

Published online by Cambridge University Press:  25 May 2016

R. Genzel
R. Genzel*
Affiliation:
Max-Planck Institut fuer extraterrestrische Physik Garching, FRG

Abstract

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High resolution near-infrared imaging and spectroscopy now gives detailed information about the structure, evolution and mass distribution in the nuclear star cluster of the Milky Way. The central parsec is powered by a cluster of luminous and helium rich, blue supergiants/Wolf-Rayet stars. The most likely scenario for the formation of the massive stars is a star formation burst a few million years ago at which time a dense gas cloud may have fallen into the center. The stellar density in the ∼ 0.3 pc radius central core is high enough that collisions with main sequence stars destroy the largest late type giant stars. Radial velocity measurements for about 300 early and late type stars between 0.1 and 5pc radius from the dynamic center now strongly favor the existence of a central dark mass of 2.5 − 3.3 × 106M⊙ (density (109M⊙pc−3, M/L2μm) ∼ 100M⊙/L⊙) within 0.1pc of the dynamic center. This central dark mass cannot be a cluster of neutron stars. It is either a compact cluster of stellar black holes or, most likely, a single massive black hole.

Type
August 23: Observations of Fundamental Properties — Continued
Information
Symposium - International Astronomical Union , Volume 174: Dynamical Evolution of Stars Clusters , 1996 , pp. 81 - 90
Copyright
Copyright © Kluwer 1996 

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