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arXiv · 1805.06131

Magnetic fields towards Ophiuchus-B derived from SCUBA-2 polarization measurements

Archana Soam·Kate Pattle·Derek Ward-Thompson·Chang Won Lee·Sarah Sadavoy·Patrick M. Koch·Gwanjeong Kim·Jungmi Kwon·Woojin Kwon·Doris Arzoumanian·David Berry·Thiem Hoang·Motohide Tamura·Sang-Sung Lee·Tie Liu·Kee-Tae Kim·Doug Johnstone·Fumitaka Nakamura·A-Ran Lyo·Takashi Onaka·Jongsoo Kim·Ray S. Furuya·Tetsuo Hasegawa·Shih-Ping Lai·Pierre Bastien·Eun Jung Chung·Shinyoung Kim·Harriet Parsons·Mark Rawlings·Steve Mairs·Sarah F. Graves·J. -F. Robitaille·Hong-Li Liu·Anthony P. Whitworth·Chakali Eswaraiah·Ramprasad Rao·Hyunju Yoo·Martin Houde·Ji-hyun Kang·Yasuo Doi·Minho Choi·Miju Kang·Simon Coude·Hua-bai Li·Masafumi Matsumura·Brenda C. Matthews·Andy Pon·James Di Francesco·Saeko S. Hayashi·Koji S. Kawabata·Shu-ichiro Inutsuka·Keping Qiu·Erica Franzmann·Per Friberg·Jane S. Greaves·Jason M. Kirk·Di Li·Hiroko Shinnaga·Sven van Loo·Yusuke Aso·Do-Young Byun·Huei-Ru Chen·Mike C. -Y. Chen·Wen Ping Chen·Tao-Chung Ching·Jungyeon Cho·Antonio Chrysostomou·Emily Drabek-Maunder·Stewart P. S. Eyres·Jason Fiege·Rachel K. Friesen·Gary Fuller·Tim Gledhill·Matt J. Griffin·Qilao Gu·Jennifer Hatchell·Wayne Holland·Tsuyoshi Inoue·Kazunari Iwasaki·Il-Gyo Jeong·Sung-ju Kang·Francisca Kemper·Kyoung Hee Kim·Mi-Ryang Kim·Kevin M. Lacaille·Jeong-Eun Lee·Dalei Li·Junhao Liu·Sheng-Yuan Liu·Gerald H. Moriarty-Schieven·Hiroyuki Nakanishi·Nagayoshi Ohashi·Nicolas Peretto·Tae-Soo Pyo·Lei Qian·Brendan Retter·John Richer·Andrew Rigby·Giorgio Savini·Anna M. M. Scaife
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Abstract

We present the results of dust emission polarization measurements of Ophiuchus-B (Oph-B) carried out using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera with its associated polarimeter (POL-2) on the James Clerk Maxwell Telescope (JCMT) in Hawaii. This work is part of the B-fields In Star-forming Region Observations (BISTRO) survey initiated to understand the role of magnetic fields in star formation for nearby star-forming molecular clouds. We present a first look at the geometry and strength of magnetic fields in Oph-B. The field geometry is traced over $\sim$0.2 pc, with clear detection of both of the sub-clumps of Oph-B. The field pattern appears significantly disordered in sub-clump Oph-B1. The field geometry in Oph-B2 is more ordered, with a tendency to be along the major axis of the clump, parallel to the filamentary structure within which it lies. The degree of polarization decreases systematically towards the dense core material in the two sub-clumps. The field lines in the lower density material along the periphery are smoothly joined to the large scale magnetic fields probed by NIR polarization observations. We estimated a magnetic field strength of 630$\pm$410 $\mu$G in the Oph-B2 sub-clump using a Davis-Chandeasekhar-Fermi analysis. With this magnetic field strength, we find a mass-to-flux ratio $\lambda$= 1.6$\pm$1.1, which suggests that the Oph-B2 clump is slightly magnetically supercritical.

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Archana Soam, Kate Pattle, Derek Ward-Thompson, Chang Won Lee, Sarah Sadavoy, Patrick M. Koch, Gwanjeong Kim, Jungmi Kwon, Woojin Kwon, Doris Arzoumanian, David Berry, Thiem Hoang, Motohide Tamura, Sang-Sung Lee, Tie Liu, Kee-Tae Kim, Doug Johnstone, Fumitaka Nakamura, A-Ran Lyo, Takashi Onaka, Jongsoo Kim, Ray S. Furuya, Tetsuo Hasegawa, Shih-Ping Lai, Pierre Bastien, Eun Jung Chung, Shinyoung Kim, Harriet Parsons, Mark Rawlings, Steve Mairs, Sarah F. Graves, J. -F. Robitaille, Hong-Li Liu, Anthony P. Whitworth, Chakali Eswaraiah, Ramprasad Rao, Hyunju Yoo, Martin Houde, Ji-hyun Kang, Yasuo Doi, Minho Choi, Miju Kang, Simon Coude, Hua-bai Li, Masafumi Matsumura, Brenda C. Matthews, Andy Pon, James Di Francesco, Saeko S. Hayashi, Koji S. Kawabata, Shu-ichiro Inutsuka, Keping Qiu, Erica Franzmann, Per Friberg, Jane S. Greaves, Jason M. Kirk, Di Li, Hiroko Shinnaga, Sven van Loo, Yusuke Aso, Do-Young Byun, Huei-Ru Chen, Mike C. -Y. Chen, Wen Ping Chen, Tao-Chung Ching, Jungyeon Cho, Antonio Chrysostomou, Emily Drabek-Maunder, Stewart P. S. Eyres, Jason Fiege, Rachel K. Friesen, Gary Fuller, Tim Gledhill, Matt J. Griffin, Qilao Gu, Jennifer Hatchell, Wayne Holland, Tsuyoshi Inoue, Kazunari Iwasaki, Il-Gyo Jeong, Sung-ju Kang, Francisca Kemper, Kyoung Hee Kim, Mi-Ryang Kim, Kevin M. Lacaille, Jeong-Eun Lee, Dalei Li, Junhao Liu, Sheng-Yuan Liu, Gerald H. Moriarty-Schieven, Hiroyuki Nakanishi, Nagayoshi Ohashi, Nicolas Peretto, Tae-Soo Pyo, Lei Qian, Brendan Retter, John Richer, Andrew Rigby, Giorgio Savini, Anna M. M. Scaife. 2018-05-16. Magnetic fields towards Ophiuchus-B derived from SCUBA-2 polarization measurements. https://doi.org/10.3847/1538-4357/aac4a6

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