1. Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263 001, India
2. School of Studies in Physics and Astrophysics, Pandit Ravishankar Shukla University, Chattisgarh 492 010, India
3. Department of Physics, University of California, 1 Shields Ave, Davis, CA 95616-5270, USA
4. Indian Institute of Astrophysics, Koramangala, Bangalore 560 034, India
5. Department of Physics & Astrophysics, University of Delhi, Delhi 110 007, India
6. Department of Physics, Indian Institute of Technology, Powai, Mumbai 400076, India
7. Kavli Institute for Astronomy and Astrophysics, Peking University, 5 Yiheyuan Road, Haidian District, Beijing 100871, China
8. Lomonosov Moscow State University, Physics Department, Vorobievy Hills, 1, Moscow 119991, Russia
9. Lomonosov Moscow State University, SAI, Universitetsky pr., 13, Moscow 119234, Russia