摘要
硬X射线和软射线光子的时延是研究高能辐射的一个重要方面 .傅里叶交叉谱常常被用于计算硬软光子之间的时延 .但是交叉谱方法不能在高于 30Hz的傅里叶频率上从CygX 1测量到有统计意义的快速光变 .由李惕碚在时域上发展的交叉相关函数方法能有效测量不同时间尺度上的时延 .利用此交叉相关分析方法 ,讨论了不同观测时期CygX 1硬态高能光子时延的性质 .分析结果表明 ,CygX 1硬态在短的时间尺度 (<0 .1秒 )上存在有意义的时间延迟 .并将短时间尺度上的观测结果和各种CygX
It is an important study aspect of the high energy radiation to study time lag between two light curves with different energies. The Fourier cross spectrum used to estimate time lag between hard and soft X ray photons. But Fourier technique can only give a significent time lag less than 30 Hz in the hard state in Cyg X 1. The modeified cross correlation function by Li Ti Pei in the time domain can measure the rapid variability down to 1 ms time scale. We analyse the hard time lags in hard state of Cyg X 1 in different observational segments by modified cross correlation function. Our results show that there are statistically significant time lags in timescales shorter than 0.1s. We compare the predications of different theoretical models of Cyg X 1 in its hard state with our results.
出处
《天文学报》
CSCD
北大核心
2001年第2期140-147,共8页
Acta Astronomica Sinica
基金
国家重点基础研究专项经费
国家科学基金资助项目!(1990 30 0 4 )
