1. Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK
2. Department of Physics, Florida State University, Tallahassee, FL 32306, USA
3. Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str 1, D-85748 Garching, Germany
4. Yunnan Observatories (YNAO), Chinese Academy of Sciences, Kunming 650216, China
5. Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650216, China
6. Center for Astronomical Mega-Science, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China
7. Physics Department and Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing 100084, China
8. Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Budapest, Konkoly-Thege út 15-17, 1121, Hungary
9. Department of Optics and Quantum Electronics, University of Szeged, Dóm tér 9, Szeged 6720, Hungary
10. Department of Astronomy, University of Texas at Austin, 2515 Speedway, Austin, TX 78712-1205, USA
11. National Astronomical Observatories of China (NAOC), Chinese Academy of Sciences, Beijing 100012, China
12. Las Cumbres Observatory, 6740 Cortona Dr. Suite 102, Goleta, CA 93117, USA
13. University of California, Santa Barbara, Department of Physics, Broida Hall, Santa Barbara, CA 93111, USA
14. Department of Physics, University of California, Davis, CA 95616, USA
15. Department of Experimental Physics, University of Szeged, Dómtér 9, Szeged 6720, Hungary
16. University of North Carolina 269 Phillips Hall, CB #3255 Chapel Hill, NC 27599, USA
17. Department of Astronomy/Steward Observatory, 933 North Cherry Avenue, Room N204, Tucson, AZ 85721, USA
18. Department of Astronomy and The Oskar Klein Centre, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden