Stellar Dynamics in the Central Parsec: 1000 Proper Motions in 100 Nights

Thomas Ott, Reinhard Genzel, Andreas Eckart, Rainer Schödel

1 Max-Planck-Institut fur extraterrestrische Physik, Giessenbachstr., 85748 Garching, Germany
2 Max-Planck-Institut fur extraterrestrische Physik, Giessenbachstr., 85748 Garching, Germany
3 I. Physikalisches Institut, Universitat zu Koln, Zulpicher Strasse 77, 50937 Koln, Germany
4 Max-Planck-Institut furr extraterrestrische Physik, Giessenbachstr., 85748 Garching, Germany

E-mail contact: ott@mpe.mpg.de

We have performed a comprehensive analysis of all near-infrared imaging data taken with the SHARP experiment at the NTT, which now cover the decade from 1992 to 2002. By developing a largely automatized approach, we were able to increase the number of measured proper motions in the Galactic Center stellar cluster by about an order of magnitude in comparison to previous work done on this issue. We thus have made astrometric positions and projected sky velocities available for about 1000 stars in the central parsec of our galaxy. This database enables us to assess the dynamical properties of the central stellar cluster with unprecedented accuracy and completeness.

In addition to the already known high velocity stars within 1" of Sgr A*, we find a number of fast stars at larger radii which show projected velocities of approximately 500 km/s. Those stars seem to be witnesses of the unusually strong interactions between the stars in this very dense cluster.

The new and extensive data on precise positions and velocities of Galactic Center cluster stars will also facilitate further analysis like anisotropy and the dynamical properties of different stellar subgroups in this region.