The JCMT BISTRO Survey: An 850/450 μm Polarization Study of NGC 2071IR in Orion B
A-Ran Lyo, Jongsoo Kim, Sarah Sadavoy, Doug Johnstone, David Berry, Kate Pattle, Woojin Kwon, Pierre Bastien, Takashi Onaka, James Di Francesco, Ji‐hyun Kang, Ray S. Furuya, Charles L. H. Hull, Motohide Tamura, Patrick M. Koch, D. Ward–Thompson, Tetsuo Hasegawa, Thiem Hoang, D. Arzoumanian, Chang Won Lee, Chin‐Fei Lee, Do‐Young Byun, Florian Kirchschlager, Yasuo Doi, Kee‐Tae Kim, Jihye Hwang, Pham Ngoc Diep, Lapo Fanciullo, Sang-Sung Lee, Geumsook Park, Hyunju Yoo, Eun Jung Chung, A. P. Whitworth, Steve Mairs, Archana Soam, Tie Liu, Xindi Tang, Simon Coudé, P. André, Tyler L. Bourke, Huei-Ru Vivien Chen, Zhiwei Chen, Wen Chen, Mike Chen, Tao-Chung Ching, Jungyeon Cho, Minho Choi, Yunhee Choi, A. Chrysostomou, Sophia Dai, C. D. Dowell, Hao-Yuan Duan, Yan Duan, David Eden, Chakali Eswaraiah, S. P. S. Eyres, Jason Fiege, Laura M. Fissel, Erica Franzmann, Per Friberg, Rachel Friesen, G. A. Fuller, T. M. Gledhill, Sarah Graves, J. S. Greaves, Matt Griffin, Qilao Gu, Ilseung Han, Jannifer Hatchell, Saeko S. Hayashi, Martin Houde, Tsuyoshi Inoue, Shu‐ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Miju Kang, Akimasa Kataoka, Koji S. Kawabata, F. Kemper, Gwanjeong Kim, Mi-Ryang Kim, Shinyoung Kim, Kyoung Hee Kim, J. M. Kirk, Masato I. N. Kobayashi, V. Könyves, Takayoshi Kusune, Jungmi Kwon, Kevin Lacaille, S. Lai, Chi-Yan Law, Jeong‐Eun Lee, Yong-Hee Lee, Hyeseung Lee, Dalei Li, Di Li, Hua-bai Li, Hongli Liu, Junhao Liu, Sheng‐Yuan Liu
Abstract
Abstract We present the results of simultaneous 450 μ m and 850 μ m polarization observations toward the massive star-forming region NGC 2071IR, a target of the BISTRO ( B -fields in STar-forming Region Observations) Survey, using the POL-2 polarimeter and SCUBA-2 camera mounted on the James Clerk Maxwell Telescope. We find a pinched magnetic field morphology in the central dense core region, which could be due to a rotating toroidal disklike structure and a bipolar outflow originating from the central young stellar object IRS 3. Using the modified Davis–Chandrasekhar–Fermi method, we obtain a plane-of-sky magnetic field strength of 563 ± 421 μ G in the central ∼0.12 pc region from 850 μ m polarization data. The corresponding magnetic energy density of 2.04 × 10 −8 erg cm −3 is comparable to the turbulent and gravitational energy densities in the region. We find that the magnetic field direction is very well aligned with the whole of the IRS 3 bipolar outflow structure. We find that the median value of polarization fractions is 3.0% at 450 μ m in the central 3′ region, which is larger than the median value of 1.2% at 850 μ m. The trend could be due to the better alignment of warmer dust in the strong radiation environment. We also find that polarization fractions decrease with intensity at both wavelengths, with slopes, determined by fitting a Rician noise model of 0.59 ± 0.03 at 450 μ m and 0.36 ± 0.04 at 850 μ m, respectively. We think that the shallow slope at 850 μ m is due to grain alignment at the center being assisted by strong radiation from the central young stellar objects.