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The (quite dark) stellar cluster around the supermassive black hole Sagittarius A* at the center of the Milky Way

Published online by Cambridge University Press:  01 July 2007

Rainer Schödel  and
A. Eckart
Rainer Schödel
Affiliation:
I.Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany email: rainer@ph1.uni-koeln.de, eckart@ph1.uni-koeln.de
A. Eckart
Affiliation:
I.Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany email: rainer@ph1.uni-koeln.de, eckart@ph1.uni-koeln.de
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Abstract

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High-resolution seeing limited and adaptive optics near-infrared imaging observations of the stellar cluster within about one parsec of the massive black hole Sagittarius A* allow us to obtain a detailed picture of the structure of the nuclear star cluster of the Milky Way. We find that the stellar number counts and the diffuse light of the unresolved stellar population can be described very well by a stellar density function in the form of a broken-power law. This agrees well with theoretical predictions on the structure of a dynamically relaxed star cluster around a massive black hole. However, the cusp slope is found to be too shallow, which may be related to mixing of different stellar populations and continuous star formation, phenomena that are not taken into account by current theory. Mass densities larger than 107 solar masses per pc3 are reached within 0.1 pc of the central black hole. Intriguingly, up to several tens of percent of the total cluster mass in the central parsec may be in the form of dark stellar remnants.

Keywords

Galaxy: centerGalaxy: nucleusGalaxy: structureinfrared: starstechniques: high angular resolution
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 3 , Symposium S245: Formation and Evolution of Galaxy Bulges , July 2007 , pp. 207 - 210
Copyright
Copyright © International Astronomical Union 2008

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