1. School of Electronics and Communication Engineering, Guangzhou University , Guangzhou 510006 , P. R. China
2. Center for Astrophysics, Guangzhou University , Guangzhou 510006 , P. R. China
3. Great Bay Center, National Astronomical Data Center , Guangzhou, Guangdong 510006 , P. R. China
4. Peng Cheng Laboratory , Shenzhen 518000 , P. R. China
5. National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101 , P. R. China