OH Survey along Sightlines of Galactic Observations of Terahertz C+
文献类型：期刊论文
| 作者 | Tang,Ningyu3,4; Li,Di3,4,5; Heiles,Carl6; Yue,Nannan3,4; Dawson,J. R.1,8; Goldsmith,Paul F.2; Kr?o,Marko3; McClure-Griffiths,N. M.7; Wang,Shen3,4; Zuo,Pei3,4 |
| 刊名 | The Astrophysical Journal
 |
| 出版日期 | 2017-04-07 |
| 卷号 | 839期号:1 |
| 关键词 | evolution ISM: clouds ISM: molecules. |
| ISSN号 | 0004-637X |
| DOI | 10.3847/1538-4357/aa67e9 |
| 英文摘要 | Abstract We have obtained OH spectra of four transitions in the ground state, at 1612, 1665, 1667, and 1720 MHz, toward 51 sightlines that were observed in the Herschel project Galactic Observations of Terahertz C+. The observations cover the longitude range of (32°, 64°) and (189°, 207°) in the northern Galactic plane. All of the diffuse OH emissions conform to the so-called “Sum Rule” of the four brightness temperatures, indicating optically thin emission conditions for OH from diffuse clouds in the Galactic plane. The column densities of the H i “halos” N(H i) surrounding molecular clouds increase monotonically with OH column density, N(OH), until saturating when cm?2 and cm?2, indicating the presence of molecular gas that cannot be traced by H i. Such a linear correlation, albeit weak, is suggestive of halos’ contribution to the UV shielding required for molecular formation. About 18% of OH clouds have no associated CO emission (CO-dark) at a sensitivity of 0.07 K, but are associated with C+ emission. A weak correlation exists between C+ intensity and OH column density for CO-dark molecular clouds. These results imply that OH seems to be a better tracer of molecular gas than CO in diffuse molecular regions. |
| 语种 | 英语 |
| WOS记录号 | IOP:0004-637X-839-1-AA67E9 |
| 出版者 | The American Astronomical Society |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/36039]  |
| 专题 | 中国科学院国家天文台 |
| 作者单位 | 1.Department of Physics and Astronomy and MQ Research Centre in Astronomy, Astrophysics and Astrophotonics, Macquarie University, NSW 2109, Australia 2.Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA 3.National Astronomical Observatories, CAS, Beijing 100012, China; nytang@nao.cas.cn, dili@nao.cas.cn 4.University of Chinese Academy of Sciences, Beijing 100049, China 5.Key Laboratory of Radio Astronomy, Chinese Academy of Science, Nanjing, 210008, China 6.Department of Astronomy, University of California, Berkeley, 601 Campbell Hall 3411, Berkeley, CA 94720-3411, USA 7.Research School for Astronomy & Astrophysics, Australian National University, Canberra, ACT 2611, Australia 8.Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710, Australia |
| 推荐引用方式 GB/T 7714 | Tang,Ningyu,Li,Di,Heiles,Carl,et al. OH Survey along Sightlines of Galactic Observations of Terahertz C+[J]. The Astrophysical Journal,2017,839(1). |
| APA | Tang,Ningyu.,Li,Di.,Heiles,Carl.,Yue,Nannan.,Dawson,J. R..,...&Wang,Jun-Jie.(2017).OH Survey along Sightlines of Galactic Observations of Terahertz C+.The Astrophysical Journal,839(1). |
| MLA | Tang,Ningyu,et al."OH Survey along Sightlines of Galactic Observations of Terahertz C+".The Astrophysical Journal 839.1(2017). |
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来源：国家天文台
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