The JCMT BISTRO Survey: A Spiral Magnetic Field in a Hub-filament Structure, Monoceros R2

Abstract We present and analyze observations of polarized dust emission at 850 μ m toward the central 1 × pc hub-filament structure Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on James Clerk Maxwell Telescope (JCMT) as part B-fields in Star-forming Region Observations survey. orientations magnetic field follow spiral Mon R2, which well described by an axisymmetric model. estimate turbulent component using angle difference between our best-fit model underlying large-scale mean field. This is used to calculate strength Davis–Chandrasekhar–Fermi method, for we also obtain distribution volume density velocity dispersion a column map derived from Herschel C 18 O ( J = 3 − 2) taken HARP JCMT, respectively. make maps strengths mass-to-flux ratios, finding that vary 0.02 3.64 mG value 1.0 ± 0.06 mG, critical ratio 0.47 0.02. Additionally, Alfvén Mach number 0.35 0.01. suggests that, fields provide resistance against gravitational collapse, pressure exceeds pressure. investigate properties each filament R2. Most filaments aligned along direction magnetically subcritical.