Magnetic fields and the triaxiality of molecular cloud cores

被引:83
作者
Basu, S [1 ]
机构
[1] Univ Western Ontario, Dept Phys & Astron, London, ON N6A 3K7, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
ISM : clouds; ISM : magnetic fields; MHD; polarization;
D O I
10.1086/312885
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We make the hypothesis that molecular cloud fragments are triaxial bodies with a large-scale magnetic field oriented along the short axis. While consistent with theoretical expectations, this idea is supported by magnetic field strength data, which show strong evidence for flattening along the direction of the mean magnetic field. It is also consistent with early submillimeter polarization data, which show that the projected direction of the magnetic field is often slightly misaligned with the projected minor axis of a molecular cloud core; i.e., the offset angle Psi is nonzero. We calculate distributions of Psi for various triaxial bodies, when viewed from a random set of viewing angles. The highest viewing probability always corresponds to Psi = 0 degrees, but there is a finite probability of viewing all nonzero Psi, including even Psi = 90 degrees; the average offset typically falls in the range of 10 degrees-30 degrees for triaxial bodies most likely to satisfy observational and theoretical constraints.
引用
收藏
页码:L103 / L106
页数:4
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