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 Furuya , Charles L. H. Hull , Motohide Tamura , Patrick M. Koch , Derek Ward-Thompson , Tetsuo Hasegawa , Thiem Hoang , Doris 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 , Anthony Whitworth , Steve Mairs , Archana Soam , Tie Liu , Xindi Tang , Simon Coudé , Philippe André , Tyler L. Bourke , Huei-Ru Vivien Chen , Zhiwei Chen , Wen Ping Chen , Mike Chen , Tao-Chung Ching , Jungyeon Cho , Minho Choi , Yunhee Choi , Antonio Chrysostomou , Sophia Dai , C. Darren Dowell , Hao-Yuan Duan , Yan Duan , David Eden , Chakali Eswaraiah , Stewart Eyres , Jason Fiege , Laura M. Fissel , Erica Franzmann , Per Friberg , Rachel Friesen , Gary Fuller , Tim Gledhill , Sarah Graves , Jane Greaves , Matt Griffin , Qilao Gu , Ilseung Han , Jannifer Hatchell , Saeko Hayashi , Martin Houde , Tsuyoshi Inoue , Shu-Ichiro Inutsuka , Kazunari Iwasaki , Il-Gyo Jeong , Miju Kang , Akimasa Kataoka , Koji Kawabata , Francisca Kemper , Gwanjeong Kim , Mi-Ryang Kim , Shinyoung Kim , Kyoung Hee Kim , Jason Kirk , Masato I. N. Kobayashi , Vera Könyves , Takayoshi Kusune , Jungmi Kwon , Kevin Lacaille , Shih-Ping Lai , Chi-Yan Law , Jeong-Eun Lee , Yong-Hee Lee , Hyeseung Lee , Dalei Li , Di Li , Hua-Bai Li , Hong-Li Liu , Junhao Liu , Sheng-Yuan Liu , Xing Lu , Masafumi Matsumura , Brenda Matthews , Gerald Moriarty-Schieven , Tetsuya Nagata , Fumitaka Nakamura , Hiroyuki Nakanishi , Nguyen Bich Ngoc , Nagayoshi Ohashi , Harriet Parsons , Nicolas Peretto , Felix Priestley , Tae-Soo Pyo , Lei Qian , Keping Qiu , Ramprasad Rao , Jonathan Rawlings , Mark G. Rawlings , Brendan Retter , John Richer , Andrew Rigby , Hiro Saito , Giorgio Savini , Anna Scaife , Masumichi Seta , Yoshito Shimajiri , Hiroko Shinnaga , Mehrnoosh Tahani , Ya-Wen Tang , Kohji Tomisaka , Le Ngoc Tram , Yusuke Tsukamoto , Serena Viti , Jia-Wei Wang , Hongchi Wang , Jinjin Xie , Hsi-Wei Yen , Jinghua Yuan , Hyeong-Sik Yun , Tetsuya Zenko , Guoyin Zhang , Chuan-Peng Zhang , Yapeng Zhang , Jianjun Zhou , Lei Zhu , Ilse de Looze , C. Darren Dowell , Sam Falle , Jean-François Robitaille (1) , Sven van Loo

1 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble

We present the results of simultaneous 450 μm and 850 μm 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 μG in the central ~0.12 pc region from 850 μm 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 μm in the central 3' region, which is larger than the median value of 1.2% at 850 μm. 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 μm and 0.36 ± 0.04 at 850 μm, respectively. We think that the shallow slope at 850 μm is due to grain alignment at the center being assisted by strong radiation from the central young stellar objects.

Keywords: Star-forming regions; Interstellar magnetic fields; Interstellar medium; Polarimetry

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

A. -Ran Lyo, Jongsoo Kim, Sarah Sadavoy, Doug Johnstone, David Berry, et al.. The JCMT BISTRO Survey: An 850/450 μm Polarization Study of NGC 2071IR in Orion B. The Astrophysical Journal, 2021, 918, ⟨10.3847/1538-4357/ac0ce9⟩. ⟨insu-03705280⟩