银河系中心附近的磁场的下限为50微高斯
Roland M Crocker1, David I Jones, Fulvio Melia
1School of Physics, Monash University, Victoria 3110, Australia. Roland.Crocker@mpi-hd.mpg.de
Nature
|January 8, 2010
概括
银河中心附近的磁场在400帕塞克 (pc) 尺度上至少为50微高斯 (microG). 这一发现解决了长达数十年的不确定性,表明银河系内高度集中的磁能密度.
科学领域:
- 天体物理学 天体物理学
- 银河系的动力学
- 等离子体物理学的物理学
背景情况:
- 几十年来,银河系中心附近的磁场强度一直不确定两个数量级.
- 之前的估计在不同尺度 (100-400帕塞克,pc) 上从6到1000微高斯 (microG) 之间.
- 这些不确定性源于关于压力平衡,均分和观测解释的不同假设.
研究的目的:
- 解决长期存在的银河系中心附近磁场振幅的不确定性.
- 为了限制磁场强度,使用先前数据和光谱分析的汇编.
- 确定磁场强度对银河系内能量密度和分布的影响.
主要方法:
- 收集和分析关于银河中心非热电波频谱的先前数据.
- 鉴定了一种归因于宇宙射线电子冷却 (bremsstrahlung到同步子) 的向下光谱断裂.
- 基于玛射线发射极限和光谱断裂特征来限制磁场强度的建模.
主要成果:
- 确定了非热性无线电频谱的向下断裂.
- 这种光谱断裂需要银河中心的磁场至少50微高斯 (microG) 在400帕塞克 (pc) 尺度上.
- 进一步考虑支持大约100微G的磁场强度,这意味着磁能的显著度.
结论:
- 银河系中心附近的磁场比以往在某些假设下推断的要强得多.
- 超过10%的银河系的磁能包含在一个很小的部分 (约. 它的体积的0.05%.
- 这些发现为银河系中心的星际介质和磁场模型提供了关键的约束.
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