1. Yunnan Observatories, Chinese Academy of Sciences , Kunming 650216, China
2. Department of Astronomy, Key Laboratory of Astroparticle Physics of Yunnan Province, Yunnan University , Kunming 650091, China
3. Center for Astronomical Mega-Science, Chinese Academy of Sciences , 20A Datun Road, Chaoyang District, Beijing 100012, China
4. University of Chinese Academy of Sciences , No.1 Yanqihu East Rd, Huairou District, Beijing 101408, China