The molecular cloud Sagittarius B2
The molecular cloud Sagittarius B2
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分子云人马座 B2
DOI：
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发表时间：
1975
期刊：
影响因子：
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通讯作者：
A. Penzias
中科院分区：
文献类型：
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作者：
N. Scoville;P. Solomon;A. Penzias
通过对CO、$sup 13$CO、CS和H$sub 2$CO （2-cm）跃迁的详细和广泛的映射，研究了Sgr B2分子云的结构。该云团由位于OH脉泽位置的致密核心和一个非常大的直径为45pc的包层组成。人马座B2是银河系中质量最大的天体之一，含有大约3倍10$sup 6$ M/sub sun/：这一估计独立于计算$sup 13$CO柱密度、应用维里定理和远红外测量得出。分子气体的平均温度T/subk/约为20K;这与发射远红外辐射的颗粒的温度相似，被认为是尘埃颗粒与H$sub 2$之间接近热平衡的证据。发现云中气体的动力学受大尺度系统运动支配，其速度不是半径的单调函数。(AIP)
The structure of the Sgr B2 molecular cloud has been studied by detailed and extensive mappings of the CO, $sup 13$CO, CS, and H$sub 2$CO (2-cm) transitions. The cloud consists of a dense core at the OH maser position plus a very large envelope 45 pc across. Sagittarius B2 is one of the most massive objects in the Galaxy, containing about 3times10$sup 6$ M/sub sun/: an estimate arrived at independently from calculated $sup 13$CO column densities, from application of the virial theorem, and from far-infrared measurements. The molecular gas has an average temperature T/subk/ of approx.20 K; that this is similar to the temperature of grains emitting far-infrared radiation is taken as evidence of near thermal equilibrium between dust grains and H$sub 2$. The dynamics of the gas in the cloud are found to be dominated by large-scale systematic motions with velocity not a monotonic function of radius. (AIP)