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银河系盘中的正电子的不对称分布,由玛射线揭示出来
Georg Weidenspointner1, Gerry Skinner, Pierre Jean
1Centre d'Etude Spatiale des Rayonnements, CNRS/UPS, BP 44346, Toulouse Cedex 4, France. Georg.Weidenspointner@hll.mpg.de
Nature
|January 11, 2008
概括
确定了导致511 keV马射线线辐射的正子的起源. 不对称的辐射表明,硬的低质量X射线二进制星 (LMXBs) 是主要的来源,而不是异国情调的暗物质.
科学领域:
- 天体物理学 天体物理学
- 高能天文学 高能天文学
- 粒子物理学 粒子物理学
背景情况:
- 电子-正子灭绝产生511 keV的马射线线辐射,几十年来从银河系中心观察到.
- 这些正子的确切起源在天体物理学中仍然是一个未解决的.
- 拟议的来源包括恒星核合成,紧物体和暗物质的消灭.
研究的目的:
- 调查来自银河系内部511 keV马射线辐射的正子子的起源.
- 为了确定在玛射线发射中观察到的不对称性是否与已知的天体物理源相关.
- 评估低质量X射线二进制星 (LMXBs) 作为主导正子源的贡献.
主要方法:
- 在银河系内部磁盘中分析511 keV马射线辐射线的空间分布.
- 观察到的马射线不对称性与硬质低质量X射线二进制星 (LMXBs) 的分布的比较.
- 从LMXBs中建模正子逃逸和毁灭率.
主要成果:
- 从银河系内盘 (距银河系中心10-50度) 发出的511 keV线辐射中检测到了明显的不对称性.
- 这种不对称性与硬的LMXBs (那些具有>20 keV光子能量排放的) 的分布密切匹配.
- 这些发现暗示,硬的LMXBs可能是正子子的主要来源,其逃逸率为每秒约10^41.
结论:
- 低质量X射线二进制星系被强烈认为是银河系中正子子的主要来源.
- 这种天体物理学解释减少了对奇特来源的必要性,例如暗物质的消灭.
- 这项研究证实,正子可以逃离LMXB并在星际介质中灭绝,产生观察到的狭窄的511 keV线.
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