DR 21(OH): A HIGHLY FRAGMENTED, MAGNETIZED, TURBULENT DENSE CORE

Journal Article · Sat Jul 20 04:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/772/1/69· OSTI ID:22121838

Girart, J. M.; Frau, P. ^[1]; Zhang, Q. ^[2]; Koch, P. M.; Tang, Y. -W.; Lai, S. -P.; Ho, P. T. P. ^[3]

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1. Institut de Ciencies de l'Espai, (CSIC-IEEC), Campus UAB, Facultat de Ciencies, C5p 2, E-08193 Bellaterra, Catalonia (Spain)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
3. Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

We present high angular resolution observations of the massive star-forming core DR21(OH) at 880 {mu}m using the Submillimeter Array (SMA). The dense core exhibits an overall velocity gradient in a Keplerian-like pattern, which breaks at the center of the core where SMA 6 and SMA 7 are located. The dust polarization shows a complex magnetic field, compatible with a toroidal configuration. This is in contrast with the large, parsec-scale filament that surrounds the core, where there is a smooth magnetic field. The total magnetic field strengths in the filament and in the core are 0.9 and 2.1 mG, respectively. We found evidence of magnetic field diffusion at the core scales, far beyond the expected value for ambipolar diffusion. It is possible that the diffusion arises from fast magnetic reconnection in the presence of turbulence. The dynamics of the DR 21(OH) core appear to be controlled energetically in equal parts by the magnetic field, magnetohydrodynamic turbulence, and the angular momentum. The effect of the angular momentum (this is a fast rotating core) is probably causing the observed toroidal field configuration. Yet, gravitation overwhelms all the forces, making this a clear supercritical core with a mass-to-flux ratio of {approx_equal} 6 times the critical value. However, simulations show that this is not enough for the high level of fragmentation observed at 1000 AU scales. Thus, rotation and outflow feedback are probably the main causes of the observed fragmentation.

• OSTI ID: 22121838
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 772; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AMBIPOLAR DIFFUSION
ANGULAR MOMENTUM
COSMIC DUST
GRAVITATION
MAGNETIC FIELDS
MAGNETIC RECONNECTION
MASS
POLARIZATION
ROTATION
SIMULATION
SPATIAL RESOLUTION
STARS
TOROIDAL CONFIGURATION
TURBULENCE
VELOCITY