Proper-motion anisotropy, rotation, and the shape of the galactic bulge

We explain the apparent proper-motion anisotropy σ_l/σ_b, = 1.15 ± aade's window (l, b) = (1°, -4°) observed by Spaenhauer, Jones, & Whitford by rotation broadening in the longitude direction. We find that the observed solid-body rotation rate of the bulge can account for the observed proper-motion anisotropy. We find also that the sample is not homogeneous in kinematics. The M giants and the late-type and/or metal-rich K giants in the sample have a bigger apparent anisotropy σ_l/σ_b and smaller intrinsic dispersion ab than the whole sample. Also, σ_r > σ_b for the metal-rich stars. We show that these anisotropies are consistent with a rapidly rotating and intrinsically anisotropical bar in the center.