Extinction Map of Baade’s Window

Recently Woźniak & Stanek proposed a new method to investigate interstellar extinction, based on two-band photometry, which uses red clump stars as a means to construct the reddening curve. I apply this method to the color-magnitude diagrams obtained by the Optical Gravitational Lensing Experiment to construct an extinction map of a 40' × 40' region of Baade's window, with resolution of ~30''. Such a map should be useful for studies of this frequently observed region of the Galactic bulge. The map and software useful for its applications are available via anonymous ftp. The total extinction A V varies from 1.26 to 2.79 mag within the 40' × 40' field of view centered on (α 2000 , δ 2000 ) = (18:03:20.9, -30:02:06), i.e., ( l , b ) = (1.001, -3.885). The ratio A V / E ( V - I ) = 2.49 ± 0.02 is determined with this new method.