1. School of Physics & Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA, UK
2. ICRAR, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
3. Arglander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany
4. SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
5. Division of Particle and Astrophysical Science, Nagoya University, Furo-Cho, Chikusa-ku, Nagoya 464-8602, Japan
6. European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany
7. Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany
8. Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ, UK
9. H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
10. Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent, Belgium
11. Sydney Institute for Astronomy, School of Physics, A28, The University of Sydney, Sydney, NSW 2006, Australia
12. School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
13. Institut d’Astrophysique Spatiale, CNRS, Université Paris-Sud, Université Paris-Saclay, Bât. 121, F-91405 Orsay Cedex, France
14. Department of Physics and Astronomy, 102 Natural Science Building, University of Louisville, Louisville, KY 40292, USA
15. Astronomy Centre, University of Sussex, Falmer, Brighton BN1 9QH, UK
16. Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg, Germany
17. Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
18. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA
19. SRON Netherlands Institute for Space Research, Landleven 12, NL-9747 AD Groningen, the Netherlands
20. Kapteyn Astronomical Institute, University of Groningen, Postbus 800, NL-9700 AV Groningen, the Netherlands