The James Clerk Maxwell telescope Legacy Survey of the Gould Belt: a molecular line study of the Ophiuchus molecular cloud
The James Clerk Maxwell telescope Legacy Survey of the Gould Belt: a molecular line study of the Ophiuchus molecular cloud
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DOI：
10.1093/mnras/stu2323
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发表时间：
2014-11
影响因子：
4.8
通讯作者：
G. White;E. Drabek-Maunder;E. Rosolowsky;D. Ward-Thompson;C. Davis;J. Gregson;J. Hatchell;M. Etxaluze;S. Stickler;J. Buckle;D. Johnstone;R. Friesen;S. Sadavoy;K. V. Natt;M. Currie;J. Richer;K. Pattle;M. Spaans;J. Francesco;M. Hogerheijde
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文献类型：
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作者：
G. White;E. Drabek-Maunder;E. Rosolowsky;D. Ward-Thompson;C. Davis;J. Gregson;J. Hatchell;M. Etxaluze;S. Stickler;J. Buckle;D. Johnstone;R. Friesen;S. Sadavoy;K. V. Natt;M. Currie;J. Richer;K. Pattle;M. Spaans;J. Francesco;M. Hogerheijde
CO、13CO 和 C18O J = 3-2 观测结果显示了蛇夫座分子云。 13CO 和 C18O 排放主要由 Oph A 团块以及 Oph B1、B2、C、E、F 和 J 区域组成。光学上较细的 C18O 谱线被用作柱密度示踪剂，由此估计引力结合能为 4.5 × 1039 J (2282 M⊙ km2 s-2)。湍流动能是 6.3 × 1038 J (320 M⊙ km2 s-2)，比这个小七倍，因此 Oph 云作为一个整体受到引力束缚。研究人员对 30 颗原恒星进行了搜寻，以寻找高速气体，其中 8 颗显示出气体流出，另外 20 颗原恒星的视线范围内有高速气体存在的证据。总流出动能为1.3 × 1038 J (67 M⊙ km2 s-2)，相当于云层湍流动能的21%。尽管流出的湍流注入很重要，但似乎并不是云中湍流的主要来源。鉴定出 105 个致密分子团块，其半径约为 0.01-0.05 pc，维里质量约为 0.1-12 M⊙，光度约为 0.001-0.1 K km s-1 pc-2，激发温度约为 10-50 K。这些与基于标准巨分子云 (GMC) 的尺寸线宽关系一致，表明比例定律延伸至 尺寸尺度为百分之一秒差距，以及太阳下质量凝结。然而，没有令人信服的证据表明大多数团块正在经历自由落体塌陷，也没有证据表明它们受到压力限制。
CO, 13CO, and C18O J = 3-2 observations are presented of the Ophiuchus molecular cloud. The 13CO and C18O emission is dominated by the Oph A clump, and the Oph B1, B2, C, E, F, and J regions. The optically thin(ner) C18O line is used as a column density tracer, from which the gravitational binding energy is estimated to be 4.5 × 1039 J (2282 M⊙ km2 s-2). The turbulent kinetic energy is 6.3 × 1038 J (320 M⊙ km2 s-2), or seven times less than this, and therefore the Oph cloud as a whole is gravitationally bound. 30 protostars were searched for high-velocity gas, with 8 showing outflows, and 20 more having evidence of high-velocity gas along their lines of sight. The total outflow kinetic energy is 1.3 × 1038 J (67 M⊙ km2 s-2), corresponding to 21 per cent of the cloud's turbulent kinetic energy. Although turbulent injection by outflows is significant, but does not appear to be the dominant source of turbulence in the cloud. 105 dense molecular clumplets were identified, which had radii ˜0.01-0.05 pc, virial masses ˜0.1-12 M⊙, luminosities ˜0.001-0.1 K km s-1 pc-2, and excitation temperatures ˜10-50 K. These are consistent with the standard Giant Molecular Cloud (GMC) based size-linewidth relationships, showing that the scaling laws extend down to size scales of hundredths of a parsec, and to subsolar-mass condensations. There is however no compelling evidence that the majority of clumplets are undergoing free-fall collapse, nor that they are pressure confined.