We construct dynamical models of the Milky Way ’ s Box/Peanut ( B/P ) bulge , using the recently measured 3D density of Red Clump Giants ( RCGs ) as well as kinematic data from the brava survey .
We match these data using the nmagic Made-to-Measure method , starting with N-body models for barred discs in different dark matter haloes .
We determine the total mass in the bulge volume of the RCGs measurement ( \pm 2.2 \times \pm 1.4 \times \pm 1.2 kpc ) with unprecedented accuracy and robustness to be 1.84 \pm 0.07 \times 10 ^ { 10 } M _ { \odot } .
The stellar mass in this volume varies between 1.25 - 1.6 \times 10 ^ { 10 } M _ { \odot } , depending on the amount of dark matter in the bulge .
We evaluate the mass-to-light and mass-to-clump ratios in the bulge and compare them to theoretical predictions from population synthesis models .
We find a mass-to-light ratio in the K-band in the range 0.8 - 1.1 .
The models are consistent with a Kroupa or Chabrier IMF , but a Salpeter IMF is ruled out for stellar ages of 10 Gyr .
To match predictions from the Zoccali IMF derived from the bulge stellar luminosity function requires \sim 40 \% or \sim 0.7 \times 10 ^ { 10 } M _ { \odot } dark matter in the bulge region .
The brava data together with the RCGs 3D density imply a low pattern speed for the Galactic B/P bulge of \Omega _ { p } = 25 - 30 { km s ^ { -1 } kpc ^ { -1 } } .
This would place the Galaxy among the slow rotators ( \R \geq 1.5 ) .
Finally , we show that the Milky Way ’ s B/P bulge has an off-centred X structure , and that the stellar mass involved in the peanut shape accounts for at least 20 \% of the stellar mass of the bulge , significantly larger than previously thought .