Stellar density profile and mass of the Milky Way bulge from VVV data

Abstract

We present the first stellar density profile of the MilkyWay bulge that reaches latitude b = 0°. The profile was derived by counting red clump stars within the colour-magnitude diagram that was constructed using the new PSF-fitting photometry from VISTA Variables in the Vía Láctea (VVV) survey data. The new stellar density map covers the area between |l| ≤ 10° and |b| ≤ 4:5° with unprecedented accuracy, allowing the stellar kinematics from the Giraffe Inner Bulge Spectroscopic Survey (GIBS) to be linked to the stellar mass density distribution. In particular, the location of the central velocity-dispersion peak from GIBS matches a high over-density in the VVV star count map. By scaling the total luminosity function (LF) obtained from all VVV fields to the LF from Zoccali et al.(2003), we obtain the first fully empirical estimate of the mass in stars and in remnants of the Galactic bulge. Within (|b| < 9:5°, |l| < 10°), the Milky Way bulge stellar mass is 2:0 ± 0:3 × 1010 M⊙.