1. Centre for Extragalactic Astronomy, Durham University, Durham DH1 3LE, UK
2. LERMA, Observatoire de Paris, PSL Research University, College de France, CNRS, Sorbonne University, Paris, France
3. Department of Physics, University of Bath, North Road, Bath BA2 7AY, USA
4. Department of Physics and Astronomy, University of Waterloo, Waterloo ON N2L 3G1, Canada
5. Centre for Astronomy & Particle Theory, University of Nottingham, Nottingham NG7 2RD, UK
6. Department of Astrophysical Sciences, 4 Ivy Lane, Princeton University, Princeton, NJ 08544, USA
7. Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904, USA
8. Center for Astrophysics | Harvard & Smithsonian, 60 Garden Str, Cambridge, MA 02138, USA
9. Department of Physics and Astronomy, University of Manitoba, Winnipeg MB R3T 2N2, Canada
10. Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, 84 Lomb Memorial Dr., NY 14623, USA
11. HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UK
12. Physics and Astronomy Department, Michigan State University, East Lansing, MI 48824, USA
13. Institute of Astronomy, Cambridge University, Madingly Road, Cambridge CB3 0HA, UK
14. Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506, USA
15. Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS 34229, F-06304 Nice cedex 4, France
16. School of Physics and Astronomy, Rochester Institute of Technology, 85 Lomb Memorial Drive, USA
17. SURFsara, P.O. Box 94613, NL-1090 GP Amsterdam, the Netherlands
18. ASTRON, Netherlands Institute for Radio Astronomy, NL-7990AA Dwingeloo, the Netherlands
19. Leiden Observatory, Leiden University, Niels Borhweg 2, NL-2333 CA Leiden, the Netherlands
20. Gemini Observatory, Northern Operation Center, 67-0 N. A’Ohoku Place, Hilo, HI, USA