JHK IMAGING OF A FIELD IN BAADE WINDOW

A 256 x 256 Hg:Cd:Te array has been used to obtain J, H, and K images of a field in Baade's Window. The data extend down to K approximately 16, which is near the base of the red giant branch at the distance of the Galactic bulge. The distribution of data points on the (K, J - K) and (J - H), H-K) diagrams is similar to that defined by previous aperture measurements. Furthermore, the redward edge of the data envelope on the (K, J - K) diagram roughly follows the giant branch of the cluster M67 to K approximately 15, indicating that the blanketing agent thought to dominate the broad-band photometric properties of super metal-rich stars must be present over a broad range of photospheric temperatures and surface gravities. The data are also used to investigate the horizontal branch content of Baade's Window, although the number of horizontal branch stars found in the current field is small, and the results should be considered as preliminary. Horizontal branch stars are found over an interval spanning almost two magnitudes in K, with the bluest of these centered near K approximately 13.2. It is also noted that the relative frequency of horizontal branch stars, measured with respect to bright red giants, is significantly lower than that derived from I band observations, a difference which may be due to blanketing at wavelengths shortward of 1-mu-m.