本計畫提出利用中子星內部結構探測器(NICER)的觀測資料，來研究X光雙星時變現象。NICER是繼上一代RXTE在2012年結束任務後，研究X光光變，特別是快速X光光變現象最佳的X光望遠鏡。X光雙星光變時間尺度範圍可小到一毫秒以下而大到數千日。它是研究中子星、恆星級黑洞與近密雙星吸積機制的重要手段之一。我們計畫以NICER的觀測資料為主，加上其他X光望遠鏡或其他波段的觀測資料，研究X光雙星時變現象，由於NICER的主要觀測目標為中子星，本計畫也將以研究中子星X光雙星為主，分為二方面，一為穩定週期的光變，包括脈衝光變與軌道光變，藉由脈衝時序分析法，精確測得吸積脈衝星中中子星自旋與雙星軌道參數，或由軌道光變取得之星曆表，探求相關物理量之演化。另一重點是非穩定週期光變現象，我們將用爾伯特-黃轉換，針對準週期震盪與超軌道光變加以分析。此外，為了以多波段的手段了解X光雙星光變特性，我們計畫加入國際大型綜合巡天望遠鏡(LSST)計畫，利用此計畫之空前巡天之能力與天文台地理優勢，將針對吸積雙星在可見光與近紅外波段之長期光變現象進行監視，配合X 光波段的監測資料，對吸積雙星長期光變之成因做一深入探討。 ;We propose using the observational data from Neutron star Interior Composition Explorer (NICER) to study the variability of X-ray binaries. NICER has been the best facility to probe the cosmic X-ray variability, especially fast variability, since the last generation X-ray timing telescope, RXTE, ended its mission in early 2012. The time scales of variability of X-ray binaries can be as short as less than 1 ms up to more than thousand days. It is important way to understand the properties of neutron star and stellar size black hole, as well as the accretion mechanism for the close binary systems. We plan to analyze the NICER observational data, as well as the data from other X-ray observatories and other wavelength bands, to study the variability of X-ray binaries. Because the primary targets of NICER are neutron stars, the neutron star X-ray binaries also become the main sources to be studied in this project. This project contains mainly two parts. First part is to investigate the stable periodic modulations, including pulsations and orbital modulations. The precise spin and orbital parameters can be yielded through pulsar timing, or the orbital ephemerides directly obtained from the modulations. They can provide us to probe the evolutions of related physical parameters. The other part is to study the non-stationary periodic variations, including the quasi-periodic oscillations and superorbital modulations, where Hilbert-Huang is the major analysis method. The NICER is able to provide the latest and high quality data the most of scientific objectives above. Furthermore, we also propose to participate an international project, Large Synoptic Survey Telescope (LSST). Utilizing the unprecedented sky survey ability and the advantage of the location of the site, it is able to process the constantly monitoring the long-term variability of X-ray binaries in optical-infrared band. Combined with the monitoring light curves from X-ray band telescopes, we are able to further understand the natures of long-term modulations of the accreting binaries.
