2000MNRAS.312L..29M

We report the first detection of CO in the bulge of M31. The ¹²CO (1-0) and (2-1) lines are both detected in the dust complex D395A/393/384, at 1.3arcmin (∼0.35kpc) from the centre. From these data and from visual extinction data, we derive a CO luminosity to reddening ratio (and a CO luminosity to H₂ column density ratio) quite similar to that observed in the local Galactic clouds. The (2-1) to (1-0) line intensity ratio points to a CO rotational temperature and a gas kinetic temperature of >10K. The molecular mass of the complex, inside a 25-arcsec (100pc) region, is 1.5x10⁴M_☉.