H I Shells in the Large Magellanic Cloud
H I Shells in the Large Magellanic Cloud
复制标题
大麦哲伦星云中的 H I 壳层
DOI：
10.1086/301116
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
M. Bessell
中科院分区：
文献类型：
--
作者：
Sungeun Kim;M. Dopita;L. Staveley;M. Bessell
最近对大麦哲伦云（LMC）的高分辨率H I观测表明，中性原子星际气体的结构主要是由大量的壳层和空穴以及复杂的螺旋结构所组成。我们提出了一个最新的目录的候选人H I超巨星和巨壳在LMC。使用所描述的选择和分类标准从H1数据立方体视觉地选择候选。23个超巨星壳，定义为那些区域的范围是远远大于H I标度的高度，编目; 103巨壳（半径小于H I气体的标度高度）编目。根据H I与Hα发射的比较，我们进一步将H I壳层分为五种不同的类型。为此，我们用塞丁泉天文台16英寸（0.41米）望远镜上的CCD照相机获得了大麦哲伦星云的新的宽视场Hα图像。20″的像素尺寸和12°的视场与H I调查很好地匹配。H I壳的尺寸分布遵循粗略的幂律，N（log R）= 1.5。当入射到H I壳层的能量恒定，壳层产生速率恒定时，得到了形式为λ（L）λ L-β的壳层光度谱，其中β = 1.75 ± 0.2.这与Kennicut、埃德加和Hodge观测到的大麦哲伦星云H II区光度谱相吻合，后者的β = 1.75 ± 0.15。包含H II区域和OB协会的H I壳似乎比没有的更迅速地膨胀，为星星形成区域的机械能的大量输入提供了直接证据。
A recent high-resolution H I survey of the Large Magellanic Cloud (LMC) shows that the structure of the neutral atomic interstellar gas is dominated by numerous shells and holes, as well as complex filamentary and spiral-type structure. We present an up-to-date catalog of candidate H I supergiant and giant shells in the LMC. The candidates are visually selected from the H I data cube using selection and classification criteria that are described. Twenty-three supergiant shells, defined as those regions whose extent is much larger than the H I scale height, are cataloged; 103 giant shells (radii less than the scale height of the H I gas) are cataloged. We further classify the H I shells into five different types, based on the comparison of the H I with their associated Hα emission. For this purpose, we obtained new wide-field Hα images of the LMC with a CCD camera mounted on a 16 inch (0.41 m) telescope at Siding Spring Observatory. The pixel size of 20″ and the field of view of 12° are well matched to the H I survey. The size distribution of H I shells follows a crude power law, N(log R) ∝ R-1.5. For constant energy input to the H I shells and a constant shell creation rate, a shell luminosity spectrum of the form ϕ(L) ∝ L-β, where β = 1.75 ± 0.2, is obtained. This agrees well with the observed H II region luminosity spectrum for the LMC of Kennicut, Edgar, & Hodge, which has β = 1.75 ± 0.15. H I shells containing H II regions and OB associations seem to expand more rapidly than those without, providing direct evidence for substantial input of mechanical energy from regions of star formation.