文章基本信息

标题：Giant molecular filaments in the Milky Way - II. The fourth Galactic quadrant
其他标题：II. The fourth Galactic quadrant⋆
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作者：J. Abreu-Vicente ; J. Abreu-Vicente ; S. Ragan 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2016
卷号：590
页码：1-20
DOI：10.1051/0004-6361/201527674
语种：English
出版社：EDP Sciences
摘要：Context. Filamentary structures are common morphological features of the cold, molecular interstellar medium (ISM). Recent studies have discovered massive, hundred-parsec-scale filaments that may be connected to the large-scale, Galactic spiral arm structure. Addressing the nature of these giant molecular filaments (GMFs) requires a census of their occurrence and properties. Aims. We perform a systematic search of GMFs in the fourth Galactic quadrant and determine their basic physical properties. Methods. We identify GMFs based on their dust extinction signatures in the near- and mid-infrared and the velocity structure probed by 13CO line emission. We use the 13CO line emission and ATLASGAL dust emission data to estimate the total and dense gas masses of the GMFs. We combine our sample with an earlier sample from literature and study the Galactic environment of the GMFs. Results. We identify nine GMFs in the fourth Galactic quadrant: six in the Centaurus spiral arm and three in inter-arm regions. Combining this sample with an earlier study using the same identification criteria in the first Galactic quadrant results in 16 GMFs, nine of which are located within spiral arms. The GMFs have sizes of 80–160 pc and 13CO-derived masses between 5−90 × 104M⊙. Their dense gas mass fractions are between 1.5–37%, which is higher in the GMFs connected to spiral arms. We also compare the different GMF-identification methods and find that emission and extinction-based techniques overlap only partially, thereby highlighting the need to use both to achieve a complete census.
关键词：ISM: general;ISM: clouds;ISM: structure