1. Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK
2. Astronomy Centre, Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
3. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
4. Sterrewacht Leiden, Universiteit Leiden, NL-2300 RA Leiden, the Netherlands
5. Royal Observatory, Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
6. National Centre for Nuclear Research, ul. Pasteura 7, PL-02-093 Warszawa, Poland
7. Aix Marseille Univ, CNRS, CNES, LAM, F-13004 Marseille, France
8. School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA, UK
9. Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu - CNRS - Université Paris, CE-Saclay, F-91190 Saint-Aubin, France
10. Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Aichi 464-8602, Japan
11. National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588, Japan
12. Institut Universitaire de France (IUF), F-75231 Paris, France
13. School of Sciences, European University Cyprus, Engomi, 1516 Nicosia, Cyprus
14. Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH, UK
15. Department of Physics and Astronomy, University of the Western Cape, 7535 Bellville, Cape Town, South Africa
16. Department of Astronomy, University of Cape Town, 7701 Rondebosch, Cape Town, South Africa
17. INAF – Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna, Italy
18. Inter-University Institute for Data Intensive Astronomy, University of the Western Cape, 7535 Bellville, Cape Town, South Africa
19. Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
20. Department of Physics and Astronomy, Oberlin College, Oberlin, OH 44074, US
21. SRON Netherlands Institute for Space Research, Landleven 12, NL-9747 AD Groningen, the Netherlands
22. Kapteyn Astronomical Institute, University of Groningen, Postbus 800, NL-9700 AV Groningen, the Netherlands