藉由近來高靈敏度及高時間解析度之巡天或監視天空的望遠鏡，天文學家發現到許多的吸積雙星會有長週期光變的現象，其週期遠大於雙星之軌道週期，儘管這種光變的確切成因仍然不十分清楚，但他們可能由吸積盤之進動、第三伴星所引發之吸積率的改變或吸積盤上之熱不穩定所造成。我們計畫用新發展出的時序分析法—希爾伯特- 黃(Hilbert-Huang)轉換將吸機雙星的長周期光變現象做有系統性的分析，這種分析方法將可解析出瞬時之光變週期與振幅。在此之前，我們進行了可行性研究，將此方法應用在高質量X 光雙星SMC X-1 由RXTE/ASM 所觀測之~13 年之久的光變曲線上，我們解析出許多前人未能分析出之現象。因此，我們相信將此技術應用在研究吸機雙星之長週期光變，會讓我們對其光變之本質有新的認知。本計畫將利用HHT 以及其他時序分析的技術，廣泛的應用在分析由巡天或監視天空的X 光與可見光望遠鏡所得之光變曲線上，以了解其光變起源與特性，而所研究之天體目標除吸積雙星外，也可擴展到其他種類的變星與活躍星核。表 With the monitoring/survey telescopes of higher sensitivity and better time resolution, long-term modulations, whose time scales are much longer than their corresponding binary orbital periods, have been seen in many of accreting binaries. The origins of such variations are still unclear but they could be caused by disk precession, accretion enhancement induced by third companion or disk thermal instability. We propose to systematically study these long-term variations using a newly developed adaptive analysis technique, Hilbert-Huang Transform (HHT), which is able to probe the instantaneous period and amplitude. A feasibility study for this new analysis technique has been processed on a High Mass X-ray Binary, SMC X-1 to trace its 40-65d variation from ~13 years’ RXTE/ASM light curve and revealed some new phenomena that were never pointed out before. We therefore have confidence that HHT is able to provide us an alternative way to resolve the nature of longer-term modulations. In this project, HHT, as well as other timing analysis techniques, will be applied to light curves obtained from X-ray or optical monitoring/survey telescopes to enhance our knowledge for the origins and properties long-term variability of accreting binaries, as well as other sources, such as different kinds of variable stars or Active Galactic Nuclei (AGNs). 研究期間：10008 ~ 10107
