1. Astrophysics, Department of Physics, University of Oxford , Keble Road, Oxford OX1 3RH, UK
2. Department of Physics and Astronomy, University of the Western Cape , Robert Sobukwe Road, 7535 Bellville, Cape Town, South Africa
3. Department of Physics and Electronics, Rhodes University , PO Box 94, Makhanda, 6140, South Africa
4. South African Radio Astronomy Observatory , 2 Fir Street, Black River Park, Observatory, Cape Town 7925, South Africa
5. Institute for Astronomy, Royal Observatory Edinburgh , Blackford Hill, Edinburgh, EH9 3HJ, UK
6. Wits Centre for Astrophysics, School of Physics, University of the Witwatersrand , 1 Jan Smuts Avenue, Johannesburg, 2000, South Africa
7. Department of Physics, University of Pretoria , Private Bag X20, Pretoria 0028, South Africa
8. Max-Planck Institut für Radioastronomie , Auf dem Hügel 69, 53121 Bonn, Germany
9. School of Physics, H.H. Wills Physics Laboratory, Tyndall Avenue, University of Bristol , Bristol, BS8 1TL, UK
10. Department of Physics and Astronomy, Rutgers, The State University of New Jersey , 136 Frelinghuysen Road, Piscataway, NJ 08854-8019, USA
11. Department of Physics and Astronomy, Università degli Studi di Padova , Vicolo dell’Osservatorio 3, I-35122, Padova, Italy
12. INAF - Osservatorio Astronomico di Padova , Vicolo dell’Osservatorio 5, I-35122, Padova, Italy
13. Department of Space, Earth and Environment, Chalmers University of Technology , Onsala Space Observatory, 43992 Onsala, Sweden
14. School of Physics and Astronomy, University of Minnesota , 116 Church St. SE, Minneapolis, MN 55455, USA
15. Minnesota Institute for Astrophysics, University of Minnesota , 116 Church St. SE, Minneapolis, MN 55455, USA
16. Cardiff Hub for Astrophysics Research & Technology, School of Physics & Astronomy, Cardiff University , Queens Buildings, The Parade, Cardiff, CF24 3AA, UK
17. Dèpartment d’Astronomie , Universitè de Genève, Chemin Pegasi 51, 1290, Versoix, Switzerland
18. ASTRON, the Netherlands Institute for Radio Astronomy , Oude Hoogeveesedijk 4,7991 PD Dwingeloo, The Netherlands
19. Kapteyn Astronomical Institute, University of Groningen , PO Box 800, 9700 AV Groningen, The Netherlands
20. Sterrenkundig Observatorium , Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent, Belgium
21. National Radio Astronomy Observatory , 520 Edgemont Road, Charlottesville, VA 22903, USA
22. Inter-University Institute for Data Intensive Astronomy, Department of Astronomy , University of Cape Town, 7701 Rondebosch, Cape Town, South Africa
23. Inter-University Institute for Data Intensive Astronomy, Department of Physics and Astronomy, University of the Western Cape , 7535 Bellville, Cape Town, South Africa
24. INAF - Istituto di Radioastronomia , via Gobetti 101, 40129 Bologna, Italy