| Title | Magnetic Fields in the Infrared Dark Cloud G34.43+0.24 |
| Authors | Soam, Archana Liu, Tie Andersson, B-G Lee, Chang Won Liu, Junhao Juvela, Mika Li, Pak Shing Goldsmith, Paul F. Zhang, Qizhou Koch, Patrick M. Kim, Kee-Tae Qiu, Keping Evans, Neal J., II Johnstone, Doug Thompson, Mark Ward-Thompson, Derek Di Francesco, James Tang, Ya-Wen Montillaud, Julien Kim, Gwanjeong Mairs, Steve Sanhueza, Patricio Kim, Shinyoung Berry, David Gordon, Michael S. Tatematsu, Ken'ichi Liu, Sheng-Yuan Pattle, Kate Eden, David McGehee, Peregrine M. Wang, Ke Ristorcelli, I. Graves, Sarah F. Alina, Dana Lacaille, Kevin M. Montier, Ludovic Park, Geumsook Kwon, Woojin Chung, Eun Jung Pelkonen, Veli-Matti Micelotta, Elisabetta R. Saajasto, Mika Fuller, Gary |
| Affiliation | NASA, Ames Res Ctr, SOFIA Sci Ctr, USRA, MS-12,N232, Moffett Field, CA 94035 USA Korea Astron & Space Sci Inst, 776 Daedeokdae Ro, Daejeon 34055, South Korea Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China Korea UST, Univ Sci & Technol, 217 Gajeong Ro, Daejeon 34113, South Korea Nanjing Univ, Sch Astron & Space Sci, 163 Xianlin Ave, Nanjing 210023, Jiangsu, Peoples R China Nanjing Univ, Key Lab Modern Astron & Astrophys, Minist Educ, Nanjing 210023, Jiangsu, Peoples R China Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA Univ Helsinki, Dept Phys, POB 64, FI-00014 Helsinki, Finland Univ Calif Berkeley, Berkeley, CA 94720 USA CALTECH, Jet Prop Lab, Pasadena, CA 90039 USA Acad Sinica, Inst Astron & Astrophys, POB 23-141, Taipei 10617, Taiwan Univ Texas Austin, Dept Astron, 2515 Speedway,Stop C1400, Austin, TX 78712 USA Kyung Hee Univ, Humanitas Coll, Global Campus, Yongin 17104, South Korea NRC Herzberg Astron & Astrophys, 5071 West Saanich Rd, Victoria, BC V9E 2E7, Canada Univ Victoria, Dept Phys & Astron, Victoria, BC V8P 1A1, Canada Univ Hertfordshire, Ctr Astrophys Res, Hatfield, Herts, England Univ Cent Lancashire, Jeremiah Horrocks Inst, Preston PR1 2HE, Lancs, England Univ Bourgogne Franche Comte, Inst UTINAM, CNRS, UMR 6213,OSU THETA, 41 Ave Observ, F-25000 Besancon, France Natl Inst Nat Sci, Natl Astron Observ Japan, Nobeyama Radio Observ, Minamisa Ku, Minamimaki, Nagano 3841305, Japan East Asian Observ, 660 NA Ohoku Pl,Univ Pk, Hilo, HI 96720 USA Natl Inst Nat Sci, Natl Astron Observ Japan, 2-21-1 Osawa, Mitaka, Tokyo 1818588, Japan Natl Tsing Hua Univ, Inst Astron, Hsinchu 30013, Taiwan Natl Tsing Hua Univ, Dept Phys, Hsinchu 30013, Taiwan Liverpool John Moores Univ, Astrophys Res Inst, IC2,Liverpool Sci Pk,146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England Coll Canyons, Dept Earth & Space Sci, Santa Clarita, CA 91355 USA Peking Univ, Kavli Inst Astron & Astrophys, 5 Yiheyuan Rd, Beijing 100871, Peoples R China Inst Rech Astrophys & Planetol, Toulouse, France Nazarbayev Univ, Kabanbay Batyr Ave 53, Nur Sultan 010000, Kazakhstan McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada Dalhousie Univ, Dept Phys & Atmospher Sci, Halifax, NS B3H 4R2, Canada Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti Franques 1, E-08028 Barcelona, Spain Univ Manchester, Jodrell Bank Ctr Astrophys, Sch Phys & Astron, Oxford Rd, Manchester M13 9PL, Lancs, England East Asian Observ, 660 NA Ohoku Pl, Hilo, HI 96720 USA |
| Keywords | ISM: magnetic fields |
| Issue Date | 2019 |
| Publisher | ASTROPHYSICAL JOURNAL |
| Abstract | We present the B-fields mapped in IRDC G34.43+0.24 using 850 mu m polarized dust emission observed with the POL-2 instrument at the James Clerk Maxwell telescope. We examine the magnetic field geometries and strengths in the northern, central, and southern regions of the filament. The overall field geometry is ordered and aligned closely perpendicular to the filament's main axis, particularly in regions containing the central clumps MM1 and MM2, whereas MM3 in the north has field orientations aligned with its major axis. The overall field orientations are uniform at large (POL-2 at 14 '' and SHARP at 10 '') to small scales (TADPOL at 2 ''.5 and SMA at 1 ''.5) in the MM1 and MM2 regions. SHARP/CSO observations in MM3 at 350 mu m from Tang et al. show a similar trend as seen in our POL-2 observations. TADPOL observations demonstrate a well-defined field geometry in MM1/MM2 consistent with MHD simulations of accreting filaments. We obtained a plane-of-sky magnetic field strength of 470 +/- 190 mu G, 100 +/- 40 mu G, and 60 +/- 34 mu G in the central, northern, and southern regions of G34, respectively, using the updated Davis-Chandrasekhar-Fermi relation. The estimated value of field strength, combined with column density and velocity dispersion values available in the literature, suggests G34 to be marginally critical with criticality parameter lambda values 0.8 +/- 0.4, 1.1 +/- 0.8, and 0.9 +/- 0.5 in the central, northern, and southern regions, respectively. The turbulent motions in G34 are sub-AlfvEnic with Alfvenic Mach numbers of 0.34 +/- 0.13, 0.53 +/- 0.30, and 0.49 +/- 0.26 in the three regions. The observed aligned B-fields in G34.43+0.24 are consistent with theoretical models suggesting that B-fields play an important role in guiding the contraction of the cloud driven by gravity. |
| URI | http://hdl.handle.net/20.500.11897/545064 |
| ISSN | 0004-637X |
| DOI | 10.3847/1538-4357/ab39dd |
| Indexed | SCI(E) EI |
| Appears in Collections: | 科维理天文与天体物理研究所 |
