A New Model for the Milky Way Bar (1209.0963v1)
Abstract: We use Schwarzschild's orbit-superposition technique to construct self-consistent models of the Galactic bar. Using $\chi2$ minimisation, we find that the best-fit Galactic bar model has a pattern speed $\Omega_{\rm p}=60 \rm{km s{-1} kpc{-1}}$, disk mass $\rm{M_{\rm d}=1.0\times10{11}M_{\odot}}$ and bar angle $\theta_{\rm bar}=20{\circ}$ for an adopted bar mass $\rm{M_{\rm bar}=2\times10{10}M_{\odot}}$. The model can reproduce not only the three-dimensional and projected density distributions but also velocity and velocity dispersion data from the BRAVA survey. We also predict the proper motions in the range $l=[-12{\circ},12{\circ}]$, $b=[-10{\circ},10{\circ}]$, which appear to be higher than observations in the longitudinal direction. The model is stable within a timescale of 0.5 Gyr, but appears to deviate from steady-state on longer timescales. Our model can be further tested by future observations such as those from GAIA.