[1] Univ Sci & Technol China, Deep Space Explorat Lab, Sch Phys Sci, Hefei 230026, Peoples R China
[2] Univ Sci & Technol China, Sch Phys Sci, Dept Astron, CAS Key Lab Res Galaxies & Cosmol, Hefei 230026, Anhui, Peoples R China
[3] Univ Sci & Technol China, Sch Astron & Space Sci, Hefei 230026, Anhui, Peoples R China
[4] Max Planck Inst Kernphys, Saupfercheckweg 1, D-69117 Heidelberg, Germany