Astrophys. J., 653, 383-397 (2006/December-2)
Large-area mapping at 850 µm. V. Analysis of the clump distribution in the Orion A South molecular cloud.
JOHNSTONE D. and BALLY J.
Abstract (from CDS):
We present results from a 2300 arcmin2 survey of the Orion A molecular cloud at 450 and 850 µm using the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope. The region mapped lies directly south of the OMC 1 cloud core and includes OMC 4, OMC 5, HH 1/2, HH 34, and L1641N. We identify 71 independent clumps in the 850 µm map and compute size, flux, and degree of central concentration in each. Comparison with isothermal, pressure-confined, self-gravitating Bonnor-Ebert spheres implies that the clumps have internal temperatures Td∼22±5 K and surface pressures log(k–1 P cm–3 K)=6.0±0.2. The clump masses span the range 0.3-22 M☉assuming a dust temperature Td∼20 K and a dust emissivity κ850=0.02 cm2/g. The distribution of clump masses is well characterized by a power law N(M)∝M–α with α=2.0±0.5 for M>3.0 M☉, indicating a clump mass function steeper than the stellar initial mass function. Significant incompleteness makes determination of the slope at lower masses difficult. A comparison of the submillimeter emission map with an H22.122 µm survey of the same region is performed. Several new Class 0 sources are revealed and a correlation is found between both the column density and degree of concentration of the submillimeter sources and the likelihood of coincident H2shock emission.
Infrared: ISM: Continuum - ISM: individual (HH 1/2) - ISM: individual (HH 34) - ISM: Individual: Alphanumeric: L1641N - ISM: individual (OMC 4) - ISM: individual (OMC 5) - ISM: individual (Orion A South) - ISM: Structure - Stars: Formation
VizieR on-line data:
<Available at CDS (J/ApJ/653/383): table1.dat>
Table 1: [JB2006] SMM JHHMMmm+DDMMm = [JB2006] NN (Nos 1-71). Paragr. 4.2.2: OMC N (No. 5) added.
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