用Lomb-Scargle算法和加权小波Z变换算法分析X射线双星的周期性

发布时间：2018-02-09 12:29

本文关键词： 时间序列分析自回归过程红噪声 Lomb-Scargle周期加权小波Z变换　出处：《湘潭大学》2014年硕士论文　论文类型：学位论文

【摘要】：天体的光变是研究天体辐射机制和内部结构变化的一个常用手段，尤其是，光变曲线中的周期性信号直接反映了中央能源的有规律性的动力学过程。在实际观测中，由于种种原因，流量密度监测数据的采样通常是不均匀的。时间采样的非均匀性给周期信号确认带来了困难，通常会在功率谱上导致出现伪峰，降低真实周期信号的幅度，有时候甚至使得真实周期信号难以识别。本文研究了非均匀采样时间序列的Lomb-Scargle周期算法和加权小波Z变换分析方法。以著名的X射线双星SS433的X射线光变曲线和HerX1以及LMC X4为例，用两种算法都检测到一个最强信号周期，与以前观测的结论一致。我们还研究了噪声对周期信号证认的影响，发现这几个周期信号的统计置信度远远超过99.96%(3.5σ)，说明它是一个真实的周期信号。其它几个幅度较弱的低频成份的统计置信度较低，，是由随机过程产生的。SS433X射线光变周期和射电数据得到的周期是一致的，分析可能与相对论性喷流的进动有关，HerX1以及LMC X4的周期信号可能是有辐射翘曲引起的。
[Abstract]:The photovariation of celestial bodies is a commonly used means to study the radiation mechanism and internal structure change of celestial bodies. In particular, the periodic signals in the phototropic curves directly reflect the regular dynamic processes of central energy. For various reasons, the sampling of flow density monitoring data is usually uneven. The nonuniformity of time sampling brings difficulties to the identification of periodic signals, which usually leads to false peaks in power spectrum and reduces the amplitude of real periodic signals. Sometimes even the real periodic signal is difficult to recognize. In this paper, the Lomb-Scargle period algorithm and the weighted wavelet Z transform analysis method for the nonuniform sampling time series are studied. For example, HerX1 and LMC X4, Two algorithms are used to detect the strongest signal period, which is consistent with the previous observations. We also study the effect of noise on the identification of periodic signals. It is found that the statistical confidence of these periodic signals is far greater than 99.96 / 3.5 蟽 / m, which indicates that it is a true periodic signal. The period obtained from the. SS433 X-ray light variation and radio data is consistent. The periodic signals of HerX1 and LMC X4 may be caused by radiation warpage, which may be related to the precession of relativistic jets.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P153

【共引文献】