利用NICER觀測資料研究X光雙星時變現象(3/3)

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.