The JCMT Legacy Survey of the Gould Belt: a first look at Orion B with HARP

The Gould Belt Legacy Survey will survey nearby star-forming regions (within 500 pc), using HARP (Heterodyne Array Receiver Programme), SCUBA-2 (Submillimetre CommonUser Bolometer Array 2) and POL-2 (Polarimeter 2) on the James Clerk Maxwell Telescope (JCMT). This paper describes the initial data obtained using HARP to observe 12 CO, 13 CO and C 18 O J = 3! 2 towards two regions in Orion B, NGC 2024 and NGC 2071. We describe the physical characteristics of the two clouds, calculating temperatures and opacities utilizing all three isotopologues. We find good agreement between temperatures calculated from CO and from dust emission in the dense, energetic regions. We determine the mass and energetics of the clouds, and of the high-velocity material seen in 12 CO emission, and compare the relative energetics of the high- and low-velocity material in the two clouds. We present a CLUMPFIND analysis of the 13 CO condensations. The slope of the condensation mass functions, at the high-mass ends, is similar to the slope of the initial mass function.