分散的来源作为银河系X射线脊的发射源
M Revnivtsev1, S Sazonov, E Churazov
1Excellence Cluster Universe, Technische Universität München, 85748, Garching, Germany. mikej@mpa-garching.mpg.de
Nature
|May 2, 2009
概括
银河脊X射线辐射,以前被认为是分散热气体,在很大程度上被分解成离散的来源. 这些来源很可能是白矮星和活跃恒星的积聚,解决了一个长期存在的天体物理学难题.
科学领域:
- 天体物理学 天体物理学
- X射线天文学X射线天文学
- 银河系天文学 银河系天文学
背景情况:
- 一个未解决的X射线发光,被称为银河脊X射线发射,已被观察到25年.
- 这种辐射的光谱与热 (约为10^8 K) 的光学薄热等离子体一致,在6.7 keV时具有突出的铁线.
- 银河盘的浅重力潜力不能限制这样一个热的星际介质,这给能量补充带来了重大挑战 (10^43 erg s^-1).
研究的目的:
- 为了研究银河系盘中未解决的X射线发光的性质.
- 为了确定观察到的X射线辐射是否来自分散的等离子体或离散的来源.
- 为了确定负责银河脊X射线辐射的天体类型.
主要方法:
- 在大约6-7 keV的能量下分析X射线数据.
- 对X射线表面亮度分布与近红外数据追踪恒星分布的比较.
- 高分辨率的X射线观测,以解决分散的发射到点源.
主要成果:
- 在6-7 keV的X射线辐射中,80%以上的看似分散的X射线辐射被分解成离散的源.
- 这些离散源的分布与银河系恒星分布相关.
- 已识别的来源很可能是白矮星和冠状活动恒星的积聚.
结论:
- 银河脊X射线辐射主要不是分散的热气体,而是来自众多微弱的离散来源的聚合辐射.
- 收缩的白矮星和活跃恒星是这种辐射的可能贡献者.
- 这一发现解决了长期以来关于银河系盘中所谓的热星际介质的能量补充问题.
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