1. Key Laboratory for Computational Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, China
2. Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, China
3. School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, China
4. Department of Physics, Institute for Computational Cosmology, Durham University , Science Laboratories, South Road, Durham DH1 3LE, UK