Molecular clumps in the W51 giant molecular cloud

作者：Parsons H^*; Thompson M A; Clark J S; Chrysostomou A

来源：Monthly Notices of the Royal Astronomical Society, 2012, 424(3): 1658-1671.

DOI：10.1111/j.1365-2966.2012.21106.x

• molecular data
• catalogues
• stars: formation
• ISM: clouds
• submillimetre: ISM

In this paper, we present a catalogue of dense molecular clumps located within the W51 giant molecular cloud (GMC). This work is based on Heterodyne Array Receiver Programme 13CO J = 32 observations of the W51 GMC and uses the automated CLUMPFIND algorithm to decompose the region into a total of 1575 clumps of which 1130 are associated with the W51 GMC. We clearly see the distinct structures of the W51 complex and the high-velocity stream previously reported. We find the clumps have characteristic diameters of 1.4?pc, excitation temperatures of 12?K, densities of 5.6 x 1021?cm-2, surface densities 0.02?g?cm-2 and masses of 90?M circle dot. We find a total mass of dense clumps within the GMC of 1.5 x 105?M circle dot, with only 1 per cent of the clumps detected by number and 4 per cent by mass found to be supercritical. We find a clump-forming efficiency of 14 +/- 1 per cent for the W51 GMC and a supercritical clump-forming efficiency of 0.5-0.5+2.3 per cent. Looking at the clump mass distribution, we find it is described by a single power law with a slope of alpha=2.4-0.1+0.2 above similar to 100?M circle dot. By comparing locations of supercritical clumps and young clusters, we see that any future star formation is likely to be located away from the currently active W51A region.

• 出版日期2012-8