The relation between magnetic and gas arms in spiral galaxies

被引:44
|
作者
Moss, D [1 ]
机构
[1] Univ Manchester, Dept Math, Manchester M13 9PL, Lancs, England
关键词
magnetic fields; MHD; galaxies; spiral;
D O I
10.1046/j.1365-8711.1998.01580.x
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The intriguing question of the origin of the arm-like magnetic structures seen between the optical spiral arms of certain spiral galaxies is addressed. Using a two-dimensional approximation to the non-linear disc dynamo equation, it is shown that gas streaming along the arms may produce such a field configuration. Another possibility is a spiral modulation of the turbulent diffusivity, associated with an enhancement of turbulence in the interstellar medium within the arms. The effects of a similar modulation of the alpha-effect are also examined. Finally, the consequences of a non-linear feedback of the large-scale field on the turbulent diffusivity ('eta-quenching') are briefly discussed.
引用
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页码:860 / 866
页数:7
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