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首页> 外文期刊>The Astrophysical journal >Large-Area Mapping at 850 μm. V. Analysis of the Clump Distribution in the Orion A South Molecular Cloud
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Large-Area Mapping at 850 μm. V. Analysis of the Clump Distribution in the Orion A South Molecular Cloud

机译:850μm的大面积贴图。五,猎户座南分子云团块分布分析

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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-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 H2 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 H2 shock emission.
机译:我们使用James Clerk Maxwell望远镜上的亚毫米级通用用户测微计阵列(SCUBA),对Orion A分子云在450和850μm处的2300 arcmin2测量结果进行了介绍。映射的区域直接位于OMC 1云核心的南部,包括OMC 4,OMC 5,HH 1/2,HH 34和L1641N。我们在850μm的图中确定了71个独立的团块,并计算了每个团块的大小,通量和中心浓度。与等温,压力限制,自重Bonnor-Ebert球的比较表明,团块的内部温度Td〜22±5 K,表面压力log(k-1 P cm-3 K)= 6.0±0.2。假设粉尘温度为Td〜20 K,粉尘发射率κ850= 0.02 cm2 g-1,则团块质量范围为0.3-22 M span。团块质量的分布通过幂律N(M)∝M-α很好地表征,对于M> 3.0M☉,α= 2.0±0.5,表明团块质量函数比恒星初始质量函数陡。显着的不完整性使得在较低质量下难以确定斜率。使用同一区域的H2 2.122μm测量值比较亚毫米发射图。揭示了几个新的0级震源,并且在柱密度和亚毫米波震源的集中度与同时发生H2冲击波的可能性之间发现了相关性。

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