THE SECOND SURVEY OF THE MOLECULAR CLOUDS IN THE LARGE MAGELLANIC CLOUD BY NANTEN. I. CATALOG OF MOLECULAR CLOUDS

Abstract

The second survey of the molecular clouds in the Large Magellanic Cloud in (CO)-C-12 (J = 1-0) was carried out by NANTEN. The sensitivity of this survey is twice as high as that of the previous NANTEN survey, leading to a detection of molecular clouds with M-CO greater than or similar to 2 x 10(4) M-circle dot. We identified 272 molecular clouds, 230 of which are detected at three or more observed positions. We derived the physical properties, such as size, line width, and virial mass, of the 164 GMCs that have an extent more than the beam size of NANTEN in both the major and minor axes. The CO luminosity and virial mass of the clouds show a good correlation of M-vir proportional to L-CO(1.1 +/- 0.1), with a Spearman rank correlation of 0.8, suggesting that the clouds are in nearly virial equilibrium. Assuming the clouds are in virial equilibrium, we derived an X-CO-factor of similar to 7 x 10(20) cm(-2) (K km s(-1))(-1). The mass spectrum of the clouds is fitted well by a power law of N-cloud(> M-CO) proportional to M-CO(-0.75 +/- 0.06) above the completeness limit of 5 x 10(4) M-circle dot. The slope of the mass spectrum becomes steeper if we fit only the massive clouds, e. g., N-cloud(> M-CO) proportional to M-CO(-1.2 +/- 0.2) for M-CO >= 3 x 10(5) M-circle dot.