1. School of Astronomy and Space Science, Nanjing University , Nanjing 210023, China
2. Key laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education , Nanjing 210023, China
3. South-Western Institute for Astronomy Research, Yunnan University , Kunming 650500, China
4. School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing 100049, China
5. Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, China
6. Department of Astronomy, School of Physical Sciences, University of Science and Technology of China , Hefei 230026, China