Wang, J-W, Lai, S-P, Eswaraiah, C et al. (130 more authors) (2019) JCMT BISTRO Survey: Magnetic Fields within the Hub-filament Structure in IC 5146. Astrophysical Journal, 876 (1). ARTN 42. ISSN 0004-637X
Abstract
We present the 850 μm polarization observations toward the IC 5146 filamentary cloud taken using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) and its associated polarimeter (POL-2), mounted on the James Clerk Maxwell Telescope, as part of the B-fields In STar forming Regions Observations. This work is aimed at revealing the magnetic field morphology within a core-scale (lesssim1.0 pc) hub-filament structure (HFS) located at the end of a parsec-scale filament. To investigate whether the observed polarization traces the magnetic field in the HFS, we analyze the dependence between the observed polarization fraction and total intensity using a Bayesian approach with the polarization fraction described by the Rice likelihood function, which can correctly describe the probability density function of the observed polarization fraction for low signal-to-noise ratio data. We find a power-law dependence between the polarization fraction and total intensity with an index of 0.56 in A V ~ 20–300 mag regions, suggesting that the dust grains in these dense regions can still be aligned with magnetic fields in the IC 5146 regions. Our polarization maps reveal a curved magnetic field, possibly dragged by the contraction along the parsec-scale filament. We further obtain a magnetic field strength of 0.5 ± 0.2 mG toward the central hub using the Davis–Chandrasekhar–Fermi method, corresponding to a mass-to-flux criticality of ~1.3 ± 0.4 and an Alfvénic Mach number of <0.6. These results suggest that gravity and magnetic field are currently of comparable importance in the HFS and that turbulence is less important.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019. The American Astronomical Society. All rights reserved. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | ISM: individual objects (IC 5146); ISM: magnetic fields; ISM: structure; polarization; radio continuum: ISM; stars: formation |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 07 Jun 2019 10:27 |
Last Modified: | 07 Jun 2019 11:12 |
Status: | Published |
Publisher: | Institute of Physics Publishing |
Identification Number: | 10.3847/1538-4357/ab13a2 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:147042 |