Extinction Map of Baade's Window

Abstract

Recently Wo\'zniak \& Stanek (1996) 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 (OGLE) to construct an extinction map of $(40')^2 $ region of Baade's Window, with resolution of $\sim30\;arcsec$. 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 {\tt anonymous ftp}. The total extinction $A_V$ varies from $1.26\;mag$ to $2.79\;mag$ within the $(40')^2 $ field of view centered on $(\alpha_{2000}, \delta_{2000}) =$ (18:03:20.9,--30:02:06), i.e. $(l,b)=(1.001,-3.885)$. The ratio $ A_V/E(V-I) = 2.49\pm0.02 $ is determined with this new method.