Red clump giant stars as tracers of Galactic structure

By isolating the red clump giant population in the color-magnitude diagrams and inverting their star counts, we can obtain directly the density distribution of the old stellar population along the line of sight. We have applied this method to several near infrared surveys and obtained information on the disc, bulge and long bar. The disc is well fitted by an exponential distribution in both the galactocentric distance and height, flared and warped in the outer parts, and with a deficit of stars in the inner in-plane regions. The long bar occupies these in-plane regions within R