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arXiv · 1007.3312

Evidence for Dynamically Important Magnetic Fields in Molecular Clouds

Hua-bai Li·Raymond Blundell·Abigail Hedden·Jonathan Kawamura·Scott Paine·Edward Tong
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Abstract

Recent observational evidence that magnetic fields are dynamically important in molecular clouds, compared to self-gravity and turbulence, is reviewed and illustrated with data from the NGC 2024 region. One piece of evidence, turbulence anisotropy, was found in the diffuse envelope of a cloud (Av~1; Heyer et al. 2008); our data further suggests turbulence anisotropy in the cloud (Av >7) and even near the cloud core (Av~100). The data also shows that magnetic fields can channel gravitational contraction even for a region with super-critical N(H2)/2Blos ratio (the ratio between the observed column density and two times the line-of-sight observed field strength), a parameter which has been widely used by observers to estimate core mass-to-flux ratios. Although the mass-to-flux ratio is constant under the flux-freezing condition, we show that N(H2)/2Blos grows with time if gravitational contraction is anisotropic due to magnetic fields.

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Hua-bai Li, Raymond Blundell, Abigail Hedden, Jonathan Kawamura, Scott Paine, Edward Tong. 2010-07-20. Evidence for Dynamically Important Magnetic Fields in Molecular Clouds. https://doi.org/10.1111/j.1365-2966.2010.17839.x

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