2006/09/06 by Doug Johnstone, John Bally · 2 citations
Chemical Engineering · Chemistry · Physics and Astronomy · #Advanced Combustion Engine Technologies #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Bolometer #Chemistry #Degree (music) #Emissivity #Flux (metallurgy) #Galaxy #James Clerk Maxwell Telescope #Luminosity #Mass distribution #Molecular cloud #Optics #Physics #Star formation #Stars #Stellar, planetary, and galactic studies #Telescope #astro-ph
paper · pdf · doi:10.1086/508852
published as Astrophys.J.653:383-397,2006 · 44 pages, 17 figures, accepted by ApJ
arxiv created 2006/09/06 · openalex publication_date 2006/12/05 · arxiv updated 2009/12/01 · openalex created_date 2017/04/07 · openalex updated_date 2026/08/05
We present results from a 2300 arcmin 2 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 T d ~ 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 T d ~ 20 K and a dust emissivity κ 850 = 0.02 cm 2 g -1 . 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 H 2 2.122 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 H 2 shock emission.