The Nuclear Cluster of the Milky Way: Total Mass and Luminosity (long
  version)
  Like many other late-type galaxies, the Milky Way contains a nuclear star
cluster. In this work we obtain the basic properties of its dominant old
stellar population. Firstly, we derive its structural properties by
constructing a stellar surface density map of the central 1000" using
extinction corrected star counts from VISTA, WFC3/IR and VLT/NACO data. We can
describe the profile with a two-component model. The inner, slightly flattened
(q=0.80+/-0.04) component is the nuclear cluster, while the outer component
corresponds to the stellar component of the circumnuclear zone. We measure for
the nuclear cluster a half-light radius of 178+/-51"~7+/-2 pc and a luminosity
of M_Ks=-16.0+/-0.5. Secondly, we enlarge the range over which detailed
dynamics are available from 1 pc to 4 pc. We obtain more than 10000 individual
proper motions from NACO data, and more than 2500 radial velocities from
VLT/SINFONI data. We determine the cluster mass by means of isotropic spherical
Jeans modeling. We fix the distance to the Galactic Center and the mass of the
supermassive black hole. We model the cluster either with a constant mass to
light ratio or with a power law mass model. For the latter we obtain a slope of
delta_M=1.18+/-0.06. Assuming spherical symmetry, we get a nuclear cluster mass
within 100" of M_100"=6.09+/- 0.53_(fix_R_0) +/- 0.97_(R_0) * 10^6 M_sun for
both modeling approaches. A model which includes the observed flattening gives
a 47% larger mass, see Chatzopoulos et al. 2015. Our results slightly favor a
core over a cusp in the mass profile. By minimizing the number of unbound stars
within 8" in our sample we obtain a distance estimate of
R$_0=8.53^{+0.21}_{-0.15}$ kpc, where an a priori relation between R_0 and SMBH
mass from stellar orbits is used. Combining our mass and flux we obtain
M/L=0.51+/-0.12 M_sun/L_(sun Ks). This is roughly consistent with a Chabrier
IMF.
