1. Department of Physics, Birla Institute of Technology and Science , Pilani 333031, India
2. Indian Institute of Astrophysics , Sarjapur Road, Koramangala, Bangalore 560034, India
3. Joint Astronomy Programme and Department of Physics, Indian Institute of Science , Bangalore 560012, India
4. Inter-University Centre for Astronomy and Astrophysics , Post Bag 4, Ganeshkhind, Pune, Maharashtra 411007, India
5. Department of Physics and Kavli Institute for Astrophysics and Space Research , Massachusetts Institute of Technology, Cambridge, MA 02139, USA
6. Aryabhatta Research Institute of Observational Sciences , Manora Peak, Nainital 263001, India