2017年9月8日
The JCMT BISTRO Survey: The Magnetic Field Strength in the Orion A Filament
The Astrophysical Journal
- 巻
- Vol.846
- 号
- No.2
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.3847/1538-4357/aa80e5
We determine the magnetic field strength in the OMC 1 region of the Orion A filament via a new implementation of the Chandrasekhar Fermi method using observations performed as part of the James Clerk Maxwell Telescope (JCMT) B-Fields In Star-forming Region Observations (BISTRO) survey with the POL-2 instrument. We combine BISTRO data with archival SCUBA-2 and HARP observations to find a plane-of-sky magnetic field strength in OMC 1 of ${B}_{athrm{pos } }=6.6m 4.7$ mG, where $elta {B}_{athrm{pos } }=4.7$ mG represents a predominantly systematic uncertainty. We develop a new method for measuring angular dispersion, analogous to unsharp masking. We find a magnetic energy density of $im 1.7imes {10}^{-7}$ J m-3 in OMC 1, comparable both to the gravitational potential energy density of OMC 1 (~10-7 J m-3) and to the energy density in the Orion BN/KL outflow (~10-7 J m-3). We find that neither the Alfvén velocity in OMC 1 nor the velocity of the super-Alfvénic outflow ejecta is sufficiently large for the BN/KL outflow to have caused large-scale distortion of the local magnetic field in the ~500 yr lifetime of the outflow. Hence, we propose that the hourglass field morphology in OMC 1 is caused by the distortion of a primordial cylindrically symmetric magnetic field by the gravitational fragmentation of the filament and/or the gravitational interaction of the BN/KL and S clumps. We find that OMC 1 is currently in or near magnetically supported equilibrium, and that the current large-scale morphology of the BN/KL outflow is regulated by the geometry of the magnetic field in OMC 1, and not vice versa.
- リンク情報
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- DOI
- https://doi.org/10.3847/1538-4357/aa80e5
- Web of Science
- https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000410064400008&DestApp=WOS_CPL
- URL
- http://iopscience.iop.org/article/10.3847/1538-4357/aa80e5/meta
- URL
- https://web.db.tokushima-u.ac.jp/cgi-bin/edb_browse?EID=339822
- URL
- https://www.scopus.com/record/display.url?eid=2-s2.0-85029528706&origin=inward
- ID情報
-
- DOI : 10.3847/1538-4357/aa80e5
- ISSN : 0004-637X
- eISSN : 1538-4357
- Web of Science ID : WOS:000410064400008