LABOCA mapping of the infrared dark cloud MSXDC G304.74+01.32

摘要

Infrared dark clouds (IRDCs) likely represent very early stages of high-massstar/star cluster formation. In this study, we aim to determine the physicalproperties and spatial distribution of dense clumps in the IRDC MSXDCG304.74+01.32 (G304.74), and bring these characteristics into relation totheories concerning the origin of IRDCs and their fragmentation into clumps andstar-forming cores. G304.74 was mapped in the 870 $\mu$m dust continuum withthe LABOCA bolometer on APEX. Archival MSX and IRAS infrared data were used tostudy the nature and properties of the submillimetre clumps within the cloud.There are 8 clumps within G304.74 which are not associated with mid-infrared(MIR) emission. Some of them are candidates for being/harbouring high-massstarless cores (HMSCs). We compared the clump masses and their spatialdistribution in G304.74 with those in several other recently studied IRDCs.There is a high likelihood that the clump mass distributions in G304.74 and inseveral other IRDCs represent the samples of the same parent distribution. Inmost cases the spatial distributions of clumps in IRDCs do not deviatesignificantly from random distributions. This is consistent with the idea thatthe origin of IRDCs, and their further sub-fragmentation down to scales ofclumps is caused by supersonic turbulence in accordance with results from giantmolecular clouds.