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The Central Dark Mass of the Milky Way

Published online by Cambridge University Press:  13 May 2016

A. Eckart
Affiliation:
I. Physikalisches Institut, Universität zu Köln, Zülpicherstraße 77, 50937 Köln, Germany
R. Genzel
Affiliation:
MPE, Garching, Postfach 1312, 85741 Garching, Germany
T. Ott
Affiliation:
MPE, Garching, Postfach 1312, 85741 Garching, Germany

Abstract

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Measurements of the proper motions and radial velocities of stars in the central cluster of the Milky Way have revealed the presence of a 2-3 million solar mass black hole at the position of the compact radio source Sagittarius A* (SgrA*). The overall stellar motions do not deviate strongly from isotropy and are consistent with a spherical isothermal stellar cluster. Speckle spectroscopy with SHARP at the NTT and slit spectroscopy with ISAAC at the VLT suggests that several of them are early type stars. This is consistent with the idea that these stars are members of an early type cluster with small angular momentum and therefore are now in the immediate vicinity of SgrA*. Most recent data now allows to measure the curvatures of the stellar orbits for a few of the stars that are closest to the center and have the largest proper motions of up to 1400 km/s. The curvatures indicate that the stars indeed orbit the central compact object and will allow to further determine its mass and compactness.

Type
The Inner Regions of Galaxies
Copyright
Copyright © Astronomical Society of the Pacific 2001 

References

Backer, D.C. 1996, Proc. of the 169th Symp. of the IAU, p.193.Google Scholar
Eckart, A., Ott, T., Genzel, R., 1999a, A&A, 352, 22.Google Scholar
Eckart, A., Genzel, R., 1997, MNRAS 284, 576.Google Scholar
Eckart, A., Genzel, R., 1996, Nature 383, 415417.CrossRefGoogle Scholar
Figer, D., et al. 2000, ApJ 533, 49.Google Scholar
Fragile, P.C., & Mathews, G.J., 2000, ApJ 542, 328.Google Scholar
Gebhardt, K., et al., 1996, AJ, 112, 105.Google Scholar
Genzel, R., Pichon, C., Eckart, , Gerhard, O.E., Ott, T., 2000, MNRAS 317, 348.Google Scholar
Genzel, R., et al. 1996, ApJ 274, 153.Google Scholar
Genzel, R., Eckart, A., Ott, T., Eisenhauer, F., 1997, MNRAS 291, 219.Google Scholar
Ghez, A., Morris, M., Becklin, E.E., Kremenek, T., Tanner, A., 2000, Nat. 407, 349.Google Scholar
Ghez, et al. 1999; ESO Symp. on “Black Holes in Binaries and Galactic Nuclei” in Sept. 1999.Google Scholar
Ghez, A. M., Klein, B. L., Morris, M., Becklin, E. E., 1998, ApJ 509, 678.Google Scholar
Greenhill, L. et al. 1995, ApJ 440, 619.CrossRefGoogle Scholar
Klein, B., Ghez, A.M., Morris, M., Becklin, E.E., 1996, ASP Conf. Vol. 102.Google Scholar
Leonard, P. J. T., Merritt, D., 1989, ApJ 339, 195.Google Scholar
Maoz, E., 1998, ApJ, 494, L13.Google Scholar
Menten, K.M., Reid, M.J., Eckart, A., Genzel, R., 1996, ApJL 475, L111114.Google Scholar
Myoshi, M., et al., 1995, Nature, 373, 127.Google Scholar
Reid, M. J., Readhead, A.C.S., Vermeulen, R.C., Treuhaft, , 1999, ApJ, 524, 816.Google Scholar
Rubilar, G.F. & Eckart, A., 2000, in preparation.Google Scholar