Results of the ESO-SEST Key Programme on CO in the Magellanic Clouds - IX. The giant LMC HII region complex N 11
Results of the ESO-SEST Key Programme on CO in the Magellanic Clouds - IX. The giant LMC HII region complex N 11
复制标题
ESO-SEST 麦哲伦星云中二氧化碳关键计划的结果 - IX。
DOI：
10.1051/0004-6361:20021582
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发表时间：
2002
影响因子：
6.5
通讯作者：
M. Rubio
中科院分区：
文献类型：
--
作者：
F. Israel;T. Graauw;L. Johansson;R. Booth;F. Boulanger;G. Garay;M. Kutner;J. Lequeux;L. Nyman;M. Rubio
第二亮的星星形成复杂的大麦哲伦云，N 11，进行了广泛的调查，在J = 1-0过渡的12 CO。在本文中，我们提出的地图和目录包含的参数29个单独的分子云的复杂性，虽然可能存在更多。分子气体在N11复合体中的分布是高度结构化的.在N 11的西南部，分子云以环或壳的形式围绕着主OB星星组合LH 9。在东北部，一连串的分子云勾勒出大麦哲伦星云中一个所谓的超巨星壳的边缘。在个别界限分明的云之间似乎只有很少的弥散分子气体，特别是在西南环。在J = 2- 112 CO跃迁中也观察到了J = 1- 012 CO跃迁中的一个云子集，在J = 2- 112 CO上以高两倍的角分辨率绘制的云图显示出更清晰的亚结构。然而，该子结构的元件的尺寸再次与映射梁的尺寸相当。对于少数云，有足够的信息可以保证尝试模拟其物理参数。它们含有相当温暖（Tkin = 60-150 K）和中等密度（nH 2 = 3000 cm −3）的气体。东北链的CO云，虽然缺乏弥漫的云间发射，是LMC的更安静的地区的特点，似乎已经受到相对较少的照片处理。然而，形成西南壳或环的云几乎没有弥漫的云间发射，并且还表现出极端光子主导区（PDR）的其他特征。
The second-brightest star formation complex in the Large Magellanic Cloud, N 11, was surveyed extensively in the J = 1-0 transition of 12 CO. In this paper we present maps and a catalogue containing the parameters of 29 individual molecular clouds in the complex, although more may be present. The distribution of molecular gas in the N 11 complex is highly structured. In the southwestern part of N 11, molecular clouds occur in a ring or shell surrounding the major OB star association LH 9. In the northeastern part, a chain of molecular clouds delineates the rim of one of the so-called supergiant shells in the LMC. There appears to be very little diffuse molecular gas in-between the individual well-defined clouds, especially in the southwestern ring. Most of the clouds have dimensions only slightly larger than those of the survey beam, i.e. diameters of 25 pc or less. A subset of the clouds mapped in J = 1-0 12 CO transition was also observed in the J = 2-1 12 CO transition, and in the corresponding transitions of 13 CO. Clouds mapped in J = 2-1 12 CO with a two times higher angular resolution show further, clear substructure. The elements of this substructure, however, have dimensions once again comparable to those of the mapping beam. For a few clouds, sufficient information was available to warrant an attempt at modelling their physical parameters. They contain fairly warm (Tkin = 60-150 K) and moderately dense (nH2 = 3000 cm −3 ) gas. The northeastern chain of CO clouds, although lacking in diffuse intercloud emission, is characteristic of the more quiescent regions of the LMC, and appears to have been subject to relatively little photo-processing. The clouds forming part of the southwestern shell or ring, however, are almost devoid of diffuse intercloud emission, and also exhibit other characteristics of an extreme photon-dominated region (PDR).