CO EMISSION FROM MOLECULAR CLOUDS IN THE CENTRAL REGION OF M31

We detected (CO)-C-12 (J = 1-0) line emission from a complex of dark c loud located at approximately 250 pc from M31's center, which is the m ost conspicuous extinction feature within the central few hundred pars ecs as observed with B, V, R, and I band CCD observations. The darkest cloud has a 30 pc size, and the virial mass is estimated to be approx imately 8.7 x 10(5) M., which is the most massive molecular cloud in t he bulge of M31. The conversion factor from CO intensity to H-2 column mass is found to be by an order of magnitude greater than that for ga lactic molecular clouds. The hydrogen mass-to-color excess ratio is al so found to be anomalously large.