Program: GN-2005B-Q-59

We propose to use NIRI to obtain deep M?? images of the central 20 x 40 arcsec of M31. The data will be used to study the properties of the most luminous AGB stars in circumstellar envelopes near the center of this galaxy. When observed at 5 microns, these stars stand out against the unresolved background of the galaxy, and can be detected to within a few arcsec of the nucleus during typical observing conditions. These data will provide a clean means of determining if an intermediate age population is present near the center of M31. For example, if the central regions of M31 contain only an old population then the brightest AGB stars will have M?? between 15.4 and 14.4 magnitudes. However, if an intermediate age population with an age of 1 Gyr or younger is present then there should be a population of stars that are at least as bright as M??=13.4.