摘要
运用自回归功率谱研究CygX－1X辐射的频谱特征，结果显示CygX－1转换态和高／软态时变频谱的连续成分，可以统一由有截断的幂律加噪声成分描述，转换态存在小于3Hz的宽峰结构及准周期振荡（QPO）成分（4－12Hz），而高／软态完全可由截断幂律谱描述，不存在显著的QPO．截断频率在各态都相当稳定，在不同态的演化与平流为主的吸积流模型（ADAF）预期的情形一致．本文结果表明，自回归功率港分析是研究X射线双星光变特征的一个有效的方法．
The method of auto-regressive power density spectrum (ARPDS) is used to analyse the frequency spectrum characteristics of Cyg X-1. Based on our results, we conclude that the power spectrum can be modelled in the same way for the transition and soft states by a broken power law plus noise. There is a wide noise component (< 3 Hz) and a QPO (4-12Hz) in each of the transition states, while in the soft state, there is no significant QPO, and its PDS can be characterized perfectly by a broken power law. The frequency cutoff in each state quite stable, and its evolution is consistent with the qualitative features predicted by the ADAF model. Our study shows that the method is effective for searching and identifying the frequency components in PDS.
基金
国家教育部博士点基金
