Large Area Mapping at 850 Microns. III. Analysis of the Clump Distribution in the Orion B Molecular Cloud

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Abstract
We present results from a survey of a 900 arcmin2 region of the Orion B molecular cloud, including NGC 2068, NGC 2071, and HH 24/25/26, at 850 μm using the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope. Following the techniques developed by Johnstone et al., we identify 75 independent objects and compute size, flux, and degree of central concentration. Comparison with isothermal, pressure-confined, self-gravitating Bonnor-Ebert spheres implies that the clumps have internal temperatures of 20-40 K and surface pressures 5.5 < log P/k < 6.5. The clump masses span 0.2-12.3 M☉ assuming typical dust temperatures and a dust emissivity κ850 = 0.01 cm2 g-1. The distribution of clump masses is well characterized by a power-law N(M) ∝ M-α with α = 1.5-2.0 for M > 1.0 M☉. Significant incompleteness makes determination of the slope at lower masses difficult. The two-point correlation function of the clump separations is measured revealing clustering on size scales r < 1.5 × 105 AU with a radial power-law exponent γ = 0.75.

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