NGC 5548的软X射线变化:能谱分析  

Soft X ray Variability of NGC 5548: Spectral Analysis

作　　者：赵永恒[1] 

机构地区：[1]中国科学院北京天文台

出　　处：《天体物理学报》1997年第4期371-379,共9页

基　　金：国家自然科学基金

摘　　要：本文给出了ＲＯＳＡＴＰＳＰＣ对ＮＧＣ５５４８定点观测的分析结果．在ＲＯＳＡＴ观测期间，ＮＧＣ５５４８的计数率显示出大振幅的变化，变化高达１４倍．硬度比与计数率呈负相关，这是由于ＮＧＣ５５４８的软Ｘ射线辐射除幂律分量外还有一个“软超”分量，分别用黑体辐射和热韧致辐射来拟合这个“软超”辐射，得出“软超”的热温度分别为：黑体辐射模型是０．０８ｋｅＶ，热韧致辐射模型是０．２３ｋｅＶ．We report the analysis results of ROSAT PSPC pointing observations of NGC 5548. The count rate of NGC 5548 shows a large amplitude variability with a factor of 14 during ROSAT observations. The hardness ratio has a negative correlation with count rate, which arises from a “soft excess” emission in addition to a power law component. We treated the “soft excess” as blackbody or thermal bremsstrahlung model. The thermal temperature of the “soft excess” is nearly constant at 0.08 keV for blackbody model and at 0.23 keV for thermal bremsstrahlung model.

关 键 词：SEYFERT星系 X射线变化 能谱分析 定点观测 星系 

分 类 号：P157.9[天文地球—天文学] P172.2