The nuclear cluster of the Milky Way: total mass and luminosity

T. K. Fritz, S. Chatzopoulos, O. Gerhard, S. Gillessen, R. Genzel, O. Pfuhl, S. Tacchella, F. Eisenhauer, T. Ott
2013 Proceedings of the International Astronomical Union  
Here we present the fundamental properties of the nuclear cluster of the Milky Way. First, we derive its structural properties by constructing a density map of the central 1000" using extinction-corrected star counts. We can describe the data with a two-component model built from Sersic profiles. The inner nearly spherical component is the nuclear cluster. The outer, strongly flattened component can be identified with the stellar component of the circumnuclear zone. Second, we enlarge the
more » ... inside which detailed dynamics are available from 1 pc to 4 pc. We use more than 10000 individual proper motions and more than 2700 radial velocities. We determine the cluster mass by means of isotropic spherical Jeans modeling. We get a nuclear cluster mass within 100" of M_100"=(6.11 ± 0.52|_fix R_0± 0.97|_R_0) × 10^6 M_, which corresponds to a total cluster mass of M_NC=(13.08 ± 2.51|_fix R_0± 2.08|_R_0) × 10^6 M_. By combination of our mass with the flux we calculate M/L=0.50 ± 0.12 M_/L_,Ks for the central 100". That is broadly consistent with a Chabrier IMF. With its mass and a luminosity of M_Ks=-15.30±0.26 the nuclear cluster is a bright and massive specimen with a typical size.
doi:10.1017/s1743921314000684 fatcat:al7firstcrbw5mgrfatflpdcd4