The nuclear star cluster
Our long-term monitoring of the Galactic Center region with NACO and SINFONI has led to a very valuable data base of stellar motions: We have measured proper motions for more than 10000 stars and radial velocities for almost 3000 stars (Fritz et al. 2016). Together with the density profile, we can determine the dynamic configuration of the nuclear cluster (Chatzopoulos et al. 2015). This allows measuring completely independent from the stellar orbits the mass of the central point source, the distance to the system, and the mass profile of the extended cluster.
Mass of and distance to Sgr A* are consistent with our results from the stellar orbits. The mass profile shows that massive black hole dominates the mass in the central parsec.