An improved bulge model for M31

New mass models are derived with emphasis on determining the bulge mass/light ratio. Inside 6 kpc, the gas rotation curve is complex and probably does not measure the true circular velocity. Therefore, the bulge M/L ratio is constrained primarily by the bulge stellar velocity dispersion. The bulge kinematics inside 1' are consistent with the bulge being an oblate isotropic rotator. Overall, the best-fitting model has an apparent bulge M/L = 5 and disk M/L = 10. The rotation curve predicted by this model rises smoothly from the center to 1 kpc and then is nearly flat out to 30 kpc. The predicted inner rotation curve forms an upper envelope to the observed complex gas kinematics.