JCMT BISTRO Survey Observations of the Ophiuchus Molecular Cloud: Dust Grain Alignment Properties Inferred Using a Ricean Noise Model
文献类型：期刊论文
| 作者 | Pattle,Kate1,2; Lai,Shih-Ping1,3; Hasegawa,Tetsuo2; Wang,Jia-Wei1; Furuya,Ray S.4; Ward-Thompson,Derek5; Bastien,Pierre6; Coudé,Simon7; Eswaraiah,Chakali8,9; Fanciullo,Lapo3 |
| 刊名 | The Astrophysical Journal
 |
| 出版日期 | 2019-07-22 |
| 卷号 | 880期号:1 |
| 关键词 | dust, extinction ISM: magnetic fields submillimeter: ISM stars: formation techniques: polarimetric |
| ISSN号 | 0004-637X |
| DOI | 10.3847/1538-4357/ab286f |
| 英文摘要 | Abstract The dependence of the polarization fraction p on total intensity I in polarized submillimeter emission measurements is typically parameterized as p?∝?I?α (α?≤?1) and used to infer dust grain alignment efficiency in star-forming regions, with an index α?=?1 indicating near-total lack of alignment of grains with the magnetic field. In this work, we demonstrate that the non-Gaussian noise characteristics of the polarization fraction may produce apparent measurements of α?～?1 even in data with significant signal-to-noise in Stokes Q, U, and I emission, and so with robust measurements of polarization angle. We present a simple model demonstrating this behavior and propose a criterion by which well-characterized measurements of the polarization fraction may be identified. We demonstrate that where our model is applicable, α can be recovered by fitting the p–I relationship with the mean of the Rice distribution without statistical debiasing of the polarization fraction. We apply our model to JCMT BISTRO Survey POL-2 850 μm observations of three clumps in the Ophiuchus molecular cloud, finding that in the externally illuminated Oph A region, α?≈?0.34, while in the more isolated Oph B and C, despite their differing star formation histories, α?～?0.6–0.7. Our results thus suggest that dust grain alignment in dense gas is more strongly influenced by the incident interstellar radiation field than by star formation history. We further find that grains may remain aligned with the magnetic field at significantly higher gas densities than has previously been believed, thus allowing investigation of magnetic field properties within star-forming clumps and cores. |
| 语种 | 英语 |
| WOS记录号 | IOP:0004-637X-880-1-AB286F |
| 出版者 | The American Astronomical Society |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/27133]  |
| 专题 | 中国科学院国家天文台 |
| 作者单位 | 1.Institute for Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan; kpattle@gapp.nthu.edu.tw 2.National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Osawa, Mitaka, Tokyo 181-8588, Japan 3.Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan 4.Institute of Liberal Arts and Sciences, Tokushima University, Minami Jousanajima-machi 1-1, Tokushima 770-8502, Japan 5.Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK 6.Centre de recherche en astrophysique du Québec & département de physique, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montréal, QC, H3C 3J7, Canada 7.SOFIA Science Center, Universities Space Research Association, NASA Ames Research Center, Moffett Field, CA 94035, USA 8.CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences, People's Republic of China 9.National Astronomical Observatories, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, People’s Republic of China 10.NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada |
| 推荐引用方式 GB/T 7714 | Pattle,Kate,Lai,Shih-Ping,Hasegawa,Tetsuo,et al. JCMT BISTRO Survey Observations of the Ophiuchus Molecular Cloud: Dust Grain Alignment Properties Inferred Using a Ricean Noise Model[J]. The Astrophysical Journal,2019,880(1). |
| APA | Pattle,Kate.,Lai,Shih-Ping.,Hasegawa,Tetsuo.,Wang,Jia-Wei.,Furuya,Ray S..,...&Soam,Archana.(2019).JCMT BISTRO Survey Observations of the Ophiuchus Molecular Cloud: Dust Grain Alignment Properties Inferred Using a Ricean Noise Model.The Astrophysical Journal,880(1). |
| MLA | Pattle,Kate,et al."JCMT BISTRO Survey Observations of the Ophiuchus Molecular Cloud: Dust Grain Alignment Properties Inferred Using a Ricean Noise Model".The Astrophysical Journal 880.1(2019). |
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来源：国家天文台
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