BAADES WINDOW AT 2.2-MU-M - THE LUMINOSITY FUNCTION AND A COMPARISON WITH THE BULGE OF M31

We have obtained K-band (2.2 mum) photometry of approximately 17 000 s tars in a 604 arcmin2 field of Baade's Window. The derived luminosity function is consistent with that obtained from unbiased samples of gri sm-selected M giants in the same region. There is no evidence that the bulge contains a significant number of stars that are bright at K and missed by grism surveys. We synthesized images of the bulge field as it would appear at the distance of M31 and show that image crowding wi ll produce an artificial enhancement of the bright end of the measured luminosity function. We conclude that the upper part of the luminosit y function in M31's bulge may be identical to that in Baade's Window.