The Color–magnitude Diagram in Baade’s Window Revisited

We have reanalyzed the OGLE V and I photometry of ∼ 500, 000 stars in Baade’s Window, and we confirm the extinction map published by Stanek (1996). However, we find that the interpretation of the OGLE color–magnitude diagram for the disk stars proposed by Paczyński et al. (1994) was incorrect: the dominant disk population in Baade’s Window is old, and we find no evidence for a large hole in the inner Galactic disk. We find evidence for a small systematic error in the OGLE photometry for stars below the “red clump”: the faint stars with V > 18 have their (V − I) color indices too red by ∼ 0.1 mag . We find tentative evidence from the OGLE and HST photometry that the the bulge main sequence turn–off point is brighter by ∼ 0.5 mag than it is in either 47 Tuc or NGC 6791, indicating that the dominant population of the Galactic bulge is considerably younger than those clusters. Subject headings: galaxy: structure – ISM: extinction – photometry On leave from N. Copernicus Astronomical Center, Bartycka 18, Warszawa 00–716, Poland Current address: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 20, Cambridge, MA 02138, USA