The JCMT BISTRO Survey: The Magnetic Field of the Barnard 1 Star-forming Region

The B-Fields In Star-Forming Regions Observations bistro Collaboration, Simon Coudé, Pierre Bastien, Martin Houde, Sarah Sadavoy, Rachel Friesen, James Di Francesco, Doug Johnstone, Steve Mairs, Tetsuo Hasegawa, Woojin Kwon, Shih Ping Lai, Keping Qiu, Derek Ward-Thompson, David Berry, Michael Chun Yuan Chen, Jason Fiege, Erica Franzmann, Jennifer Hatchell, Kevin LacailleBrenda C. Matthews, Gerald H. Moriarty-Schieven, Andy Pon, Philippe André, Doris Arzoumanian, Yusuke Aso, Do Young Byun, Chakali Eswaraiah, Huei Ru Chen, Wen Ping Chen, Tao Chung Ching, Jungyeon Cho, Minho Choi, Antonio Chrysostomou, Eun Jung Chung, Yasuo Doi, Emily Drabek-Maunder, C. Darren Dowell, Stewart P.S. Eyres, Sam Falle, Per Friberg, Gary Fuller, Ray S. Furuya, Tim Gledhill, Sarah F. Graves, Jane S. Greaves, Matt J. Griffin, Qilao Gu, Saeko S. Hayashi, Thiem Hoang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We present the POL-2 850 μm linear polarization map of the Barnard 1 clump in the Perseus molecular cloud complex from the B-fields In STar-forming Region Observations survey at the James Clerk Maxwell Telescope. We find a trend of decreasing polarization fraction as a function of total intensity, which we link to depolarization effects toward higher-density regions of the cloud. We then use the polarization data at 850 μm to infer the plane-of-sky orientation of the large-scale magnetic field in Barnard 1. This magnetic field runs north-south across most of the cloud, with the exception of B1-c, where it turns more east-west. From the dispersion of polarization angles, we calculate a turbulence correlation length of 5.0 ±2.″5 (1500 au) and a turbulent-to-total magnetic energy ratio of 0.5 ±0.3 inside the cloud. We combine this turbulent-to-total magnetic energy ratio with observations of NH3 molecular lines from the Green Bank Ammonia Survey to estimate the strength of the plane-of-sky component of the magnetic field through the Davis-Chandrasekhar-Fermi method. With a plane-of-sky amplitude of 120 ±60 μG and a criticality criterion λ c = 3.0 ±1.5, we find that Barnard 1 is a supercritical molecular cloud with a magnetic field nearly dominated by its turbulent component.

Original languageEnglish
Article number88
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 1 Jun 2019


  • ISM: clouds
  • ISM: individual objects (Barnard 1)
  • ISM: magnetic fields
  • polarization
  • stars: formation
  • submillimeter: ISM


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