Abstract
Abstract 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.
Highlights
Magnetic fields are expected to influence the process of star formation, but their exact role at each evolutionary stage is not yet understood
Knowledge of magnetic field strength is crucial in order to determine whether magnetic fields are important in star formation processes
The blue box represents the central 2 5 × 2 5 region, within which an angle dispersion is derived for magnetic field strength measurement using the Davis–Chandrasekhar–Fermi method (DCF) method
Summary
It is advisable to refer to the publisher’s version if you intend to cite from the work. N. Kobayashi , Vera Könyves , Takayoshi Kusune , Jungmi Kwon , Kevin Lacaille59,60 , Shih-Ping Lai19,34 , Chi-Yan Law45,61 , Jeong-Eun Lee , Yong-Hee Lee , Hyeseung Lee , Dalei Li63, Di Li37 , Hua-Bai Li45 , Hong-Li Liu, Junhao Liu65,66 , Sheng-Yuan Liu , Xing Lu17 , Masafumi Matsumura , Brenda Matthews4,5 , Gerald Moriarty-Schieven , Tetsuya Nagata , Fumitaka Nakamura69,70 , Hiroyuki Nakanishi, Nguyen Bich Ngoc, Nagayoshi Ohashi , Harriet Parsons , Nicolas Peretto, Felix Priestley, Tae-soo Pyo47,70 , Lei Qian , Keping Qiu65,66 , Ramprasad Rao , Jonathan Rawlings , Mark G. Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, Peoples Republic of China. CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences, Peoples Republic of China. National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012, Peoples Republic of China. Received 2021 January 11; revised 2021 June 17; accepted 2021 June 17; published 2021 September 14
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