“Missing Link” Clouds in the Southern Galactic Plane Survey
“Missing Link” Clouds in the Southern Galactic Plane Survey
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DOI：
10.1086/430296
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发表时间：
2004-12
期刊：
影响因子：
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通讯作者：
D. Kavars;J. Dickey;J. Dickey;N. McClure-Griffiths;B. Gaensler;A. J. Green
中科院分区：
文献类型：
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作者：
D. Kavars;J. Dickey;J. Dickey;N. McClure-Griffiths;B. Gaensler;A. J. Green
我们提出了一个自动化的例行搜索H I自吸收功能内的南银河平面调查（SGPS）。这些数据是由澳大利亚望远镜紧凑阵列（ATCA）和帕克斯射电望远镜拍摄的，涵盖了银河平面上3° × 105°的天空。我们应用我们的例程，这整个区域，并获得自旋温度和列密度为70个较大的HISA复合物，发现自旋温度范围从6至41 K与H I数密度的几个cm-3。这些“缺失的环节”云填补了致密分子云和弥散原子云之间的自旋温度和密度差距。我们比较了H I发射与12 CO发射，发现~60%的检测到的H I自吸收在空间和速度与分子对应物相关。这可能是由于分子/原子气体转变。我们还比较了H I自吸收与银河系旋臂，并讨论了使用它作为旋臂示踪剂的可能性。
We present an automated routine to search for H I self-absorption features within the Southern Galactic Plane Survey (SGPS). The data were taken with the Australia Telescope Compact Array (ATCA) and the Parkes Radio Telescope and encompass 3° × 105° of sky in the Galactic plane. We apply our routine to this entire region and derive spin temperatures and column densities for 70 of the larger HISA complexes, finding spin temperatures ranging from 6 to 41 K with H I number densities of a few cm-3. These "missing link" clouds fill in the spin temperature and density gaps between dense molecular clouds and diffuse atomic clouds. We compare the H I emission with 12CO emission and find that ~60% of detected H I self-absorption is correlated in space and in velocity with a molecular counterpart. This is potentially due to a molecular/atomic gas transition. We also compare H I self-absorption with Galactic spiral arms and discuss the possibility of using it as a spiral arm tracer.