Insights on the Milky Way bulge formation from the correlations between kinematics and metallicity

Understand

Two main scenarios for the formation of the Galactic bulge are invoked, the first one through gravitational collapse or hierarchical merging of subclumps, the second through secular evolution of the Galactic disc.

• We aim to constrain the formation of the Galactic bulge through studies of the correlation between kinematics and metallicities in Baade's Window (l=1, b=-4) and two other fields along the bulge minor axis (l=0, b=-6 and b=-12).
• We combine the radial velocity and the [Fe/H] measurements obtained with FLAMES/GIRAFFE at the VLT with a spectral resolution of R=20000, plus for the Baade's Window field the OGLE-II proper motions, and compare these with published N-body simulations of the Galactic bulge.
• We confirm the presence of two distinct populations in Baade's Window found in Hill et al.