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Keywords:

  • Galaxy: bulge;
  • Galaxy: centre;
  • Galaxy: formation;
  • Galaxy: kinematics and dynamics;
  • Galaxy: nucleus;
  • Galaxy: structure

ABSTRACT

We use Schwarzschild's orbit-superposition technique to construct self-consistent models of the Galactic bar. Using χ2 minimization, we find that the best-fitting Galactic bar model has a pattern speed Ωp = 60 km s−1 kpc−1, disc mass Md = 1.0 × 1011 M and bar angle θbar = 20° for an adopted bar mass Mbar = 2 × 1010 M. The model can reproduce not only the three-dimensional and projected density distributions but also velocity and velocity dispersion data from the Bulge Radial Velocity Assay (BRAVA) survey. We also predict the proper motions in the range l = [−12°, 12°], b = [−10°, 10°], which appear to be higher than observations in the longitudinal direction. The model is stable within a time-scale of 0.5 Gyr, but appears to deviate from steady state on longer time-scales. Our model can be further tested by future observations such as those from GAIA.