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Paper: Kinematics of the Old Stellar Population at the Galactic Centre
Volume: 439, The Galactic Center: a Window to the Nuclear Environment of Disk Galaxies
Page: 232
Authors: Trippe, S.; Gillessen, S.; Gerhard, O. E.; Bartko, H.; Fritz, T. K.; Eisenhauer, F.; Ott, T.; Dodds-Eden, K.; Genzel, R.; Maness, H. L.; Martins, F.
Abstract: We discuss the kinematic properties of the old, (several Gyrs) late-type CO-absorption star population among the Galactic centre (GC) cluster stars. This cluster is composed of a central supermassive black hole (Sgr A*) and a self-gravitating system of stars. Understanding its kinematics thus offers the opportunity to understand the dynamical interaction between a central point mass and the surrounding stars in general, especially in view of understanding other galactic nuclei. We applied AO-assisted, near-infrared imaging and integral-field spectroscopy using the instruments NAOS/CONICA and SINFONI at the VLT. We obtained proper motions for 5445 stars and 3D velocities for 664 stars. We detect for the first time significant cluster rotation in the sense of the general Galactic rotation in proper motions. Out of the 3D velocity dispersion, we derive an improved statistical parallax for the GC of R0 = 8.07 ± 0.32stat ± 0.13sys kpc. The distribution of 3D stellar speeds can be approximated by local Maxwellian distributions. Kinematic modelling provides deprojected 3D kinematic parameters, including the mass profile of the cluster. Overall, the GC late-type cluster is described well as a uniform, isotropic, rotating, dynamically relaxed system. The results presented at this conference have been published in Trippe et al. (2008).
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