1. Department of Astronomy, Xiamen University, Xiamen, Fujian 361005, China
2. Jiujiang Research Institute of Xiamen University, Jiujiang 332000, China
3. Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011, Yunnan Province, China
4. Center for Astronomical Mega-Science, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China
5. Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011, China
6. College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang, Henan 473061, China
7. Guangxi Key Laboratory for Relativistic Astrophysics, Department of Physics, Guangxi University, Nanning 530004, China