TY - JOUR
T1 - The JCMT BISTRO Survey: A Spiral Magnetic Field in a Hub-filament Structure, Monoceros R2
AU - BISTRO
AU - Hwang, Jihye
AU - Kim, Jongsoo
AU - Pattle, Kate
AU - Lee, Chang Won
AU - Koch, Patrick M.
AU - Johnstone, Doug
AU - Tomisaka, Kohji
AU - Whitworth, Anthony
AU - Furuya, Ray S.
AU - Kang, Ji-hyun
AU - Lyo, A-Ran
AU - Chung, Eun Jung
AU - Arzoumanian, Doris
AU - Park, Geumsook
AU - Kwon, Woojin
AU - Kim, Shinyoung
AU - Tamura, Motohide
AU - Kwon, Jungmi
AU - Soam, Archana
AU - Han, Ilseung
AU - Hoang, Thiem
AU - Kim, Kyoung Hee
AU - Onaka, Takashi
AU - Chakali, Eswaraiah
AU - Ward-Thompson, Derek
AU - Liu, Hong-Li
AU - Tang, Xindi
AU - Chen, Wen Ping
AU - Matsumura, Masafumi
AU - Hoang, Thuong Duc
AU - Chen, Zhiwei
AU - Gouellec, Valentin J. M. Le
AU - Kirchschlager, Florian
AU - Poidevin, Fr ed erick
AU - Bastien, Pierre
AU - Qiu, Keping
AU - Hasegawa, Tetsuo
AU - Lai, Shih-Ping
AU - Byun, Do-Young
AU - Cho, Jungyeon
AU - Choi, Minho
AU - Choi, Youngwoo
AU - Choi, Yunhee
AU - Jeong, Il-Gyo
AU - Kang, Miju
AU - Kim, Hyosung
AU - Kim, Kee-tae
AU - Parsons, Harriet
AU - Chrysostomou, Antonio
AU - Gledhill, Tim
N1 - © 2022. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/
PY - 2022/12/10
Y1 - 2022/12/10
N2 - We present and analyze observations of polarized dust emission at 850 $\mu$m towards the central 1 pc $\times$ 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the BISTRO (B-fields in Star-forming Region Observations) survey. The orientations of the magnetic field follow the spiral structure of Mon R2, which are well-described by an axisymmetric magnetic field model. We estimate the turbulent component of the magnetic field using the angle difference between our observations and the best-fit model of the underlying large-scale mean magnetic field. This estimate is used to calculate the magnetic field strength using the Davis-Chandrasekhar-Fermi method, for which we also obtain the distribution of volume density and velocity dispersion using a column density map derived from $Herschel$ data and the C$^{18}$O ($J$ = 3-2) data taken with HARP on the JCMT, respectively. We make maps of magnetic field strengths and mass-to-flux ratios, finding that magnetic field strengths vary from 0.02 to 3.64 mG with a mean value of 1.0 $\pm$ 0.06 mG, and the mean critical mass-to-flux ratio is 0.47 $\pm$ 0.02. Additionally, the mean Alfv\'en Mach number is 0.35 $\pm$ 0.01. This suggests that in Mon R2, magnetic fields provide resistance against large-scale gravitational collapse, and magnetic pressure exceeds turbulent pressure. We also investigate the properties of each filament in Mon R2. Most of the filaments are aligned along the magnetic field direction and are magnetically sub-critical.
AB - We present and analyze observations of polarized dust emission at 850 $\mu$m towards the central 1 pc $\times$ 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the BISTRO (B-fields in Star-forming Region Observations) survey. The orientations of the magnetic field follow the spiral structure of Mon R2, which are well-described by an axisymmetric magnetic field model. We estimate the turbulent component of the magnetic field using the angle difference between our observations and the best-fit model of the underlying large-scale mean magnetic field. This estimate is used to calculate the magnetic field strength using the Davis-Chandrasekhar-Fermi method, for which we also obtain the distribution of volume density and velocity dispersion using a column density map derived from $Herschel$ data and the C$^{18}$O ($J$ = 3-2) data taken with HARP on the JCMT, respectively. We make maps of magnetic field strengths and mass-to-flux ratios, finding that magnetic field strengths vary from 0.02 to 3.64 mG with a mean value of 1.0 $\pm$ 0.06 mG, and the mean critical mass-to-flux ratio is 0.47 $\pm$ 0.02. Additionally, the mean Alfv\'en Mach number is 0.35 $\pm$ 0.01. This suggests that in Mon R2, magnetic fields provide resistance against large-scale gravitational collapse, and magnetic pressure exceeds turbulent pressure. We also investigate the properties of each filament in Mon R2. Most of the filaments are aligned along the magnetic field direction and are magnetically sub-critical.
KW - astro-ph.GA
U2 - 10.3847/1538-4357/ac99e0
DO - 10.3847/1538-4357/ac99e0
M3 - Article
SN - 0004-637X
VL - 941
SP - 51
EP - 69
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 51
ER -