Polarimetric and Photometric Investigation of the Dark Globule LDN 1225: Distance, Extinction Law, and Magnetic Fields

doi:10.3847/1538-4357/ab0a0c

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	Polarimetric and Photometric Investigation of the Dark Globule LDN 1225: Distance, Extinction Law, and Magnetic Fields
	Eswaraiah,Chakali 2,3,4,5; Lai,Shih-Ping 2; Ma,Yuehui 6,8; Pandey,Anil K.9; Jose,Jessy 1; Chen,Zhiwei 6; Samal,Manash R.10; Wang,Jia-Wei 2; Sharma,Saurabh 9; Ojha,D. K.7
刊名	The Astrophysical Journal
	2019-04-16
卷号	875 期号:1
关键词	dust, extinction ISM: clouds local interstellar matter magnetic fields polarization
ISSN号	0004-637X
DOI	10.3847/1538-4357/ab0a0c
英文摘要	Abstract We present results based on the optical R-band observations of the polarization of 280 stars distributed toward the dark globule LDN 1225. Parallaxes from Gaia data release 2 along with the polarization data of ～200 stars have been used to (a) constrain the distance of LDN 1225 as 830?±?83 pc, (b) determine the contribution of interstellar polarization, and (c) characterize the dust properties and delineate the magnetic field (B-field) morphology of LDN 1225. We find that B-fields are more organized and exhibit a small dispersion of 12°. Using the 12CO molecular line data from the Purple Mountain Observatory, along with the column density and dispersion in B-fields, we estimate the B-field strength to be ～56?±?10 μG, the ratio of magnetic to turbulent pressure to be ～3?±?2, and the ratio of mass to magnetic flux (in units of the critical value) to be <1. These results indicate the dominant role of B-fields in comparison to turbulence and gravity in rendering the cloud support. B-fields are aligned parallel to the low-density parts (traced by a 12CO map) of the cloud; in contrast, they are neither parallel nor perpendicular to the high-density core structures (traced by 13CO and C18O maps). LDN 1225 hosts two 70 μm sources, which seem to be low-mass Class 0 sources. The ratio of total to selective extinction derived using optical and near-infrared photometric data is found to be anomalous (RV = 3.4), suggesting the growth of dust grains in LDN 1225. The polarization efficiency of dust grains follows a power law with an index of ?0.7, implying that optical polarimetry traces B-fields in the outer parts of the cloud.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:0004-637X-875-1-AB0A0C
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/25982]
专题	中国科学院国家天文台
作者单位	1.Indian Institute of Science Education and Research Tirupati, Rami Reddy Nagar, Karakambadi Road, Mangalam (P.O.), Tirupati 517 507, India 2.Institute of Astronomy, National Tsing Hua University (NTHU), 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan, Republic of China eswaraiahc@nao.cas.cn, eswaraiahc@outlook.com 3.CAS Key Laboratory of FAST, NAOC, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China 4.National Astronomical Observatories, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, People’s Republic of China 5.Indian Institute of Astrophysics, Koramangala 2nd Block, Bengaluru 560 034, India 6.Purple Mountain Observatory and Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008, People’s Republic of China 7.Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India 8.University of Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, People’s Republic of China 9.Aryabhatta Research Institute of Observational Sciences (ARIES), Manora-peak, Nainital, Uttarakhand-state, 263002, India 10.Physical Research Laboratory (PRL), Navrangpura, Ahmedabad 380 009, Gujarat, India
推荐引用方式 GB/T 7714	Eswaraiah,Chakali,Lai,Shih-Ping,Ma,Yuehui,et al. Polarimetric and Photometric Investigation of the Dark Globule LDN 1225: Distance, Extinction Law, and Magnetic Fields[J]. The Astrophysical Journal,2019,875(1).
APA	Eswaraiah,Chakali.,Lai,Shih-Ping.,Ma,Yuehui.,Pandey,Anil K..,Jose,Jessy.,...&Ojha,D. K..(2019).Polarimetric and Photometric Investigation of the Dark Globule LDN 1225: Distance, Extinction Law, and Magnetic Fields.The Astrophysical Journal,875(1).
MLA	Eswaraiah,Chakali,et al."Polarimetric and Photometric Investigation of the Dark Globule LDN 1225: Distance, Extinction Law, and Magnetic Fields".The Astrophysical Journal 875.1(2019).