An observational study of GMCs in the Magellanic Clouds with the ASTE telescope

We report the results of the submillimeter observations with the ASTE 10 m telescope toward the giant molecular clouds (GMCs) in the Magellanic Clouds to reveal the physical properties of dense molecular gas, the principle sites of star and cluster formation. Six GMCs in the Large Magellanic Cloud have been mapped in the ¹²CO(J = 3 - 2) transition and 32 clumps are identified in these GMCs at a resolution of 5 pc. These data are combined with ¹²CO(J = 1 - 0) and ¹³CO(J = 1 - 0) results and compared with LVG calculations to derive the density and temperature of clumps. The derived density and temperature are distributed in wide ranges. We have made small mapping observations in the ¹³CO(J = 3 - 2) transition toward 9 representative peak positions of clumps to determine the density and temperature of clumps. These physical properties are constrained well and there are differences in density and temperature among clumps. We suggest that these differences of clump properties represent an evolutionary sequence of GMCs in terms of density increase leading to star formation.