Observations of individual star-forming regions in the nucleus of M33

The CO emission from the nucleus of M33 has been observed with the Owens Valley Millimeter Interferometer at 20 pc resolution, sufficient to begin to resolve clouds comparable to the giant molecular clouds in the Galaxy. The properties of the three clouds detected in M33 are similar to those observed in the Galaxy. Masses derived using both the virial theorem and the observed CO flux are in reasonable agreement. Three-color CCD data obtained at the Canada-France-Hawaii telescope are used to provide a direct lower-limit estimate of the number of stars in the field more massive than 15 solar masses. The molecular gas in this nuclear field has formed at least 1 percent of its mass into high-mass stars during the last 10 to the 7th yr. 19 references