Open AccessMolecular clumps in the W51 giant molecular cloud
Author(s) -
Parsons H.,
Thompson M. A.,
Clark J. S.,
Chrysostomou A.
Publication year - 2012
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2012.21106.x
Subject(s) - physics , molecular cloud , astrophysics , supercritical fluid , star formation , astronomy , stars , thermodynamics
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 13 CO J = 3–2 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 × 10 21 cm −2 , surface densities 0.02 g cm −2 and masses of 90 M ⊙ . We find a total mass of dense clumps within the GMC of 1.5 × 10 5 M ⊙ , 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 + 2.3per cent. Looking at the clump mass distribution, we find it is described by a single power law with a slope of α = 2 . 4 − 0.1 + 0.2above ∼100 M ⊙ . 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.