论文标题
活性银核时间序列周期性的二维相关分析
Two-dimensional correlation analysis of periodicity in active galactic nuclei time series
论文作者
论文摘要
活跃的银河核（AGN）是具有固有，明显和随机变化的最强大的来源之一。他们的时间序列的随机性是如此微妙，以至于模糊了多个振荡和嘈杂的振荡之间的边界。这对分析这种时间序列的挑战构成了挑战，因为视觉检查和预先效率化方法都无法识别其中的振荡信号。因此，需要一种客观的定期检测方法。在这里，我们回顾了一种新的数据分析方法，该方法将时间序列的二维相关性（2D）与强大的高斯过程方法结合在一起。为了证明这项技术的实用性，我们将其应用于两个示例问题，这些问题没有充分利用：抑制了重新编号的人工时间序列模仿AGN时间序列和新发表的观察到的时间序列的时间序列变化的外观AGN（CL AGN）NGC 3516。这两种类型的时间序列中的方法成功地检测到了该方法的周期性。 NGC 3516中$ \ sim 4 $ yr的确定周期性使我们能够推测，如果在其积聚光盘（AD）中形成的热不稳定性在类似于检测到的周期性的时间表上，则AD半径可能为$ \ sim 0.0024 $ PC。
The active galactic nuclei (AGN) are among the most powerful sources with an inherent, pronounced and random variation of brightness. The randomness of their time series is so subtle as to blur the border between aperiodic fluctuations and noisy oscillations. This poses challenges to analysing of such time series because neither visual inspection nor pre-exisitng methods can identify well oscillatory signals in them. Thus, there is a need for an objective method for periodicity detection. Here we review our a new data analysis method that combines a two-dimensional correlation (2D) of time series with the powerful methods of Gaussian processes. To demonstrate the utility of this technique, we apply it to two example problems which were not exploited enough: damped rednoised artificial time series mimicking AGN time series and newly published observed time series of changing look AGN (CL AGN) NGC 3516. The method successfully detected periodicities in both types of time series. Identified periodicity of $\sim 4$ yr in NGC 3516 allows us to speculate that if the thermal instability formed in its accretion disc (AD) on a time scale resembling detected periodicity then AD radius could be $\sim 0.0024$ pc.
