1. Xi’an Institute of Optics and Precision Mechanics of CAS , 710119 Xi’an, China
2. University of Chinese Academy of Sciences , 100049 Beijing, China
3. Department of Physics and Astronomy, University College London , Gower Street, London, WC1E 6BT, UK
4. European Space Agency (ESA) , ESA Office, Space Telescope Science Institute (STScI), 3700 San Martin Drive, Baltimore, MD 21218, USA
5. INAF-Osservatorio Astrofisico di Torino , Via Osservatorio 20, I-10025 Pino Torinese (TO), Italy
6. INAF-Istituto di Astrofisica e Planetologia Spaziali , Via del Fosso del Cavaliere 100, I-00133 Rome, Italy