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ID 116823
Title Alternative
Dust polarization in OMC-1
Author
Pattle, Kate National University of Ireland Galway|National Tsing Hua University
Lai, Shih-Ping National Tsing Hua University|Academia Sinica Institute of Astronomy and Astrophysics
Wright, Melvyn University of California
Coudé, Simon Universities Space Research Association
Plambeck, Richard University of California
Hoang, Thiem Korea Astronomy and Space Science Institute|University of Science and Technology
Tang, Ya-Wen Academia Sinica Institute of Astronomy and Astrophysics
Bastien, Pierre Université de Montréal
Eswaraiah, Chakali Chinese Academy of Sciences
Hwang, Jihye Korea Astronomy and Space Science Institute|University of Science and Technology
Inutsuka, Shu-ichiro Nagoya University
Kim, Kee-Tae Korea Astronomy and Space Science Institute|University of Science and Technology
Kirchschlager, Florian University College London
Kwon, Woojin Seoul National University|Korea Astronomy and Space Science Institute
Lee, Chang Won Korea Astronomy and Space Science Institute|University of Science and Technology
Liu, Sheng-Yuan Academia Sinica Institute of Astronomy and Astrophysics
Lyo, Aran Korea Astronomy and Space Science Institute
Ohashi, Nagayoshi Academia Sinica Institute of Astronomy and Astrophysics
Rawlings, Mark G. East Asian Observatory
Tahani, Mehrnoosh National Research Council Canada
Tamura, Motohide National Institutes of Natural Sciences|The University of Tokyo
Soam, Archana Universities Space Research Association
Wang, Jia-Wei Academia Sinica Institute of Astronomy and Astrophysics
Ward-Thompson, Derek University of Central Lancashire
Keywords
techniques: polarimetric
stars: formation
ISM: dust, extinction
ISM: magnetic fields
submillimetre: ISM
Content Type
Journal Article
Description
We present ALMA Band 7 polarization observations of the OMC-1 region of the Orion molecular cloud. We find that the polarization pattern observed in the region is likely to have been significantly altered by the radiation field of the >104 L⊙ high-mass protostar Orion Source I. In the protostar’s optically thick disc, polarization is likely to arise from dust self-scattering. In material to the south of Source I – previously identified as a region of ‘anomalous’ polarization emission – we observe a polarization geometry concentric around Source I. We demonstrate that Source I’s extreme luminosity may be sufficient to make the radiative precession time-scale shorter than the Larmor time-scale for moderately large grains (⁠>0.005−0.1μm), causing them to precess around the radiation anisotropy vector (k-RATs) rather than the magnetic field direction (B-RATs). This requires relatively unobscured emission from Source I, supporting the hypothesis that emission in this region arises from the cavity wall of the Source I outflow. This is one of the first times that evidence for k-RAT alignment has been found outside of a protostellar disc or AGB star envelope. Alternatively, the grains may remain aligned by B-RATs and trace gas infall on to the Main Ridge. Elsewhere, we largely find the magnetic field geometry to be radial around the BN/KL explosion centre, consistent with previous observations. However, in the Main Ridge, the magnetic field geometry appears to remain consistent with the larger-scale magnetic field, perhaps indicative of the ability of the dense Ridge to resist disruption by the BN/KL explosion.
Journal Title
Monthly Notices of the Royal Astronomical Society
ISSN
13652966
Publisher
Oxford University Press|The Royal Astronomical Society
Volume
503
Issue
3
Start Page
3414
End Page
3433
Published Date
2021-03-04
Rights
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
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DOI (Published Version)
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language
eng
TextVersion
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departments
Liberal Arts and Sciences