A Schwarzschild model of the Galactic bar with initial density from N-body simulations

Using the potential from N-body simulations, we construct the Galactic bar models with the Schwarzschild method. By varying the pattern speed and the position angle of the bar, we find that the best-fitting bar model has pattern speed Ωp = 40 km s−1 kpc−1, and bar angle θbar = 45°. N-body simulations show that the best-fitting model is stable for more than 1.5 Gyr. Combined with the results in Wang et al., we find that the bar angle and/or the pattern speed are not well constrained by Bulge Radial Velocity Assay data in our Schwarzschild models. The proper motions predicted from our model are slightly larger than those observed in four fields. In the future, more kinematic data from the ground- and space-based observations will enable us to refine our model of the Milky Way bar.