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The JCMT BISTRO survey: the distribution of magnetic field strengths toward the OMC-1 region

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.3847/1538-4357/abf3c4
AuthorSearch for: ORCID identifier: https://orcid.org/0000-0001-7866-2686; Search for: ORCID identifier: https://orcid.org/0000-0002-1229-0426; Search for: ORCID identifier: https://orcid.org/0000-0002-8557-3582; Search for: ORCID identifier: https://orcid.org/0000-0003-4022-4132; Search for: ORCID identifier: https://orcid.org/0000-0001-7474-6874; Search for: ORCID identifier: https://orcid.org/0000-0003-2777-5861; Search for: ORCID identifier: https://orcid.org/0000-0002-8975-7573; Search for: 1ORCID identifier: https://orcid.org/0000-0002-6773-459X; Search for: ORCID identifier: https://orcid.org/0000-0003-0646-8782; Search for: ORCID identifier: https://orcid.org/0000-0002-3179-6334; Search for: ORCID identifier: https://orcid.org/0000-0002-1959-7201; Search for: 1ORCID identifier: https://orcid.org/0000-0001-8749-1436; Search for: ORCID identifier: https://orcid.org/0000-0003-4761-6139; Search for: ORCID identifier: https://orcid.org/0000-0002-5286-2564; Search for: ORCID identifier: https://orcid.org/0000-0002-3036-0184; Search for: ORCID identifier: https://orcid.org/0000-0003-2412-7092; Search for: ORCID identifier: https://orcid.org/0000-0002-6510-0681; Search for: ORCID identifier: https://orcid.org/0000-0003-2815-7774; Search for: ORCID identifier: https://orcid.org/0000-0002-9907-8427; Search for: ORCID identifier: https://orcid.org/0000-0002-6386-2906; Search for: ORCID identifier: https://orcid.org/0000-0001-7379-6263; Search for: ORCID identifier: https://orcid.org/0000-0001-7491-0048; Search for: ORCID identifier: https://orcid.org/0000-0002-6906-0103; Search for: ORCID identifier: https://orcid.org/0000-0002-6956-0730; Search for: ORCID identifier: https://orcid.org/0000-0003-2011-8172; Search for: ORCID identifier: https://orcid.org/0000-0001-8467-3736; Search for: ORCID identifier: https://orcid.org/0000-0001-5431-2294; Search for: ORCID identifier: https://orcid.org/0000-0002-8234-6747; Search for: ORCID identifier: https://orcid.org/0000-0002-4154-4309; Search for: ORCID identifier: https://orcid.org/0000-0003-3343-9645; Search for: ORCID identifier: https://orcid.org/0000-0003-1140-2761; Search for: ORCID identifier: https://orcid.org/0000-0003-3010-7661; Search for: ORCID identifier: https://orcid.org/0000-0003-2017-0982; Search for: ORCID identifier: https://orcid.org/0000-0003-1853-0184; Search for: ORCID identifier: https://orcid.org/0000-0002-5093-5088; Search for: ORCID identifier: https://orcid.org/0000-0001-5522-486X; Search for: ORCID identifier: https://orcid.org/0000-0002-0794-3859
Affiliation
  1. National Research Council of Canada. Herzberg Astronomy and Astrophysics
FunderSearch for: National Research Foundation of Korea; Search for: Bureau of International Cooperation, Chinese Academy of Sciences; Search for: MEXT ∣ Japan Society for the Promotion of Science
FormatText, Article
Subjectdense interstellar clouds; star forming regions; polarimetry; interstellar magnetic fields
Abstract
Measurement of magnetic field strengths in a molecular cloud is essential for determining the criticality of magnetic support against gravitational collapse. In this paper, as part of the JCMT BISTRO survey, we suggest a new application of the Davis–Chandrasekhar–Fermi (DCF) method to estimate the distribution of magnetic field strengths in the OMC-1 region. We use observations of dust polarization emission at 450 and 850 μm, and C¹⁸O (3–2) spectral line data obtained with the JCMT. We estimate the volume density, the velocity dispersion, and the polarization angle dispersion in a box, 40'' × 40'' (5×5 pixels), which moves over the OMC-1 region. By substituting three quantities in each box with the DCF method, we get magnetic field strengths over the OMC-1 region. We note that there are very large uncertainties in the inferred field strengths, as discussed in detail in this paper. The field strengths vary from 0.8 to 26.4 mG, and their mean value is about 6 mG. Additionally, we obtain maps of the mass-to-flux ratio in units of a critical value and the Alfvén Mach number. The central parts of the BN–KL and South (S) clumps in the OMC-1 region are magnetically supercritical, so the magnetic field cannot support the clumps against gravitational collapse. However, the outer parts of the region are magnetically subcritical. The mean Alfvén Mach number is about 0.4 over the region, which implies that the magnetic pressure exceeds the turbulent pressure in the OMC-1 region.
Publication date
PublisherIOP
In
  • The Astrophysical Journal 913, no. 2, 85 (27 May 2021).
LanguageEnglish
Peer reviewedYes
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Record identifier966a2a37-cf51-4703-bf3c-d0596bfb039e
Record created2023-05-11
Record modified2023-05-11
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