谱分析的CLEAN方法及其在激变变星TT Ari短周期振荡分析中的应用

THE CLEAN METHOD OF SPECTRAL ANALYSIS AND ITS APPLICATION IN ANALYZING THE SHORT PERIOD OSCILLATIONS OF CATACLYSMIC VARIABLE TT ARI

对适用于非等间隔时间序列的一维ＣＬＥＡＮ谱分析方法进行了研究，用模拟信号进行了检验，证实了它也适用于有噪声的序列，但谱质量和噪声强度密切相关．把这种方法应用到激变变星ＴＴＡｒｉ的测光资料分析中。

Various methods of spectral analysis have been extensively used in all branches of astronomy to reveal the periodic processes, which are important to understand the structure and evolution of celestial objects. A series of studies have been conducted to investigate the reliability and sensitivity of these methods. In this work, which is the second paper of the series, the CLEAN spectral analysis method for unequally spaced data is discussed and the method is tested with modeling signals. The effectiveness of the CLEAN method has been confirmed for time series with noises. Its advantage in removing sidelobes is significant. The inversions of CLEAN spectra reproduce the initial time series with some reductions in amplitudes. This method has been applied to analyze the photometric data of the cataclysmic variable TT Ari. The 19.8 and 19.3min quasi periodic oscillations have been detected in blue and yellow lights, respectively. The origin of 20min oscillations will be investigated in a separate paper.