Structure and Mass Distribution of the Milky Way Bulge and Disk

This article summarizes the structural parameters of the Galactic bulge and disk, and discusses the interpretation of the bulge microlensing observations and the determination of the Milky Way’s luminous mass from the terminal velocity curve and the Oort limit. The bulge is a rotating bar with corotation radius around 4 kpc. The NIR disk has a short scale-length. The measured surface density of the local disk is in good agreement with the prediction of a maximum NIR disk model for the Milky Way. The preliminary new value for the microlensing optical depth of clump giant sources is within 1.7σ of the prediction by the maximum NIR disk model, while the optical depth for all sources is still significantly higher. These results imply that cold dark matter cannot dominate inside the solar radius.