A complete CO survey of the Large Magellanic Cloud

Abstract

A complete CO survey of the central 6 deg x 6 deg of the LMC was performed in order to determine the distribution of molecular clouds. At least 10 percent of the region studied exhibits CO line emission, with peak line temperatures of order 0.15 K. The emission is dominated by an extremely large complex of molecular clouds extending south from 30 Doradus for nearly 2400 pc. There is an extended high-velocity CO component in the vicinity of 30 Doradus itself. Positions, masses, other physical characteristics, and related objects at other wavelengths are given for the 40 identified molecular clouds. The clouds follow a relation between CO luminosity and linewidth similar to that of Galactic clouds, but for a given linewidth appear about six times fainter, suggesting that CO luminosity scales roughly with metallicity or gas-to-dust ratio. The total mass of molecular clouds in the LMC is estimated to be 140 million solar, implying a ratio of molecular to atomic mass over the survey region of about 30 percent.