1. Department of Physics, University of California , Santa Barbara, CA 93106 , USA
2. Leiden Observatory, Leiden University , Niels Bohrweg 2, NL-2333 CA Leiden , the Netherlands
3. Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117 Heidelberg , Germany
4. Institute for Theoretical Physics, Heidelberg University , Philosophenweg 12, D-69120 Heidelberg , Germany
5. Lawrence Berkeley National Laboratory , 1 Cyclotron Rd, Berkeley, CA 94720 , USA
6. Department of Physics and Astronomy, University of California , Riverside, CA 92521 , USA
7. Canadian Institute for Theoretical Astrophysics, University of Toronto , 60 St George St, Toronto, ON M5S 3H8 , Canada
8. INAF – Osservatorio Astronomico di Trieste , Via Tiepolo 11, I-34143 Trieste , Italy
9. IFPU-Institute for Fundamental Physics of the Universe , via Beirut 2, I-34151 Trieste , Italy
10. Scuola Normale Superiore , Piazza dei Cavalieri 7, I-56126 Pisa , Italy
11. MIT Kavli Institute for Astrophysics and Space Research , 77 Massachusetts Avenue, Cambridge, MA 02139 , USA
12. Kavli Institute for Cosmology and Institute of Astronomy , Madingley Road, Cambridge CB3 0HA , UK
13. Institute for Astronomy, University of Edinburgh , Blackford Hill, Edinburgh EH9 3HJ , UK
14. Tata Institute of Fundamental Research , Homi Bhabha Road, Mumbai 400005 , India
15. Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611 , Australia