1. Department of Physics, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa
2. Wits Centre for Astrophysics, School of Physics, University of the Witwatersrand, 1 Jan Smuts Avenue 2000, South Africa
3. Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
4. Department of Physics and Electronics, Rhodes University, PO Box 94, Grahamstown 6140, Eastern Cape, South Africa
5. Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
6. South African Radio Astronomy Observatory, 2 Fir Street, Observatory 7925, South Africa
7. The Inter-University Institute for Data Intensive Astronomy (IDIA), Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
8. Department of Physics and Astronomy, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, South Africa
9. Faculty of Physics, Ludwig-Maximilians-Universität, Scheinerstr. 1, Munich D-81679, Germany
10. The Inter-University Institute for Data Intensive Astronomy (IDIA), Department of Physics and Astronomy, University of the Western Cape, Bellville 7535, South Africa
11. ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, Dwingeloo NL-7990 AA, the Netherlands
12. Kapteyn Astronomical Institute, University of Groningen, PO Box 800, Groningen NL-9700 AV, the Netherlands
13. Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía, Granada E-18008, Spain
14. School of Science, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia