1. Armagh Observatory and Planetarium, College Hill , Armagh BT61 9DG, UK
2. INAF − Osservatorio Astronomico di Cagliari , Via della Scienza 5, I-09047, Selargius, CA, Italy
3. Max-Plank-Institut für Radioastronomie , Auf dem Hügel 69, D-53121 Bonn, Germany
4. Department of Physics and Electronics, Rhodes University , PO Box 94, Makhanda 6140, South Africa
5. Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , Belfast BT7 INN, UK
6. Department of Astronomy, University of Cape Town , Private Bag X3, Rondebosch 7701, South Africa
7. Netherlands Institute for Radio Astronomy (ASTRON) , Oude Hoogeveensedijk 4, NL-7991 PD Dwingeloo, The Netherlands
8. Dipartimento di Fisica e Astronomia ‘G. Galilei’, Università di Padova , vicolo dell’Osservatorio 3, I-35122 Padova, Italy
9. INAF - Osservatorio Astronomico di Padova , vicolo dell’Osservatorio 2, I-35122 Padova, Italy
10. Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute , D-44780 Bochum, Germany
11. School of Physics and Astronomy, Cardiff University, Queens Buildings The Parade , Cardiff, CF24 3AA, UK
12. Kapteyn Astronomical Institute, University of Groningen , PO Box 800, NL−9700 AV Groningen, the Netherlands
13. The Inter-University Institute for Data Intensive Astronomy, Department of Astronomy, University of Cape Town , Private Bag X3, Rondebosch, 7701, South Africa
14. Instituto de Astrofísica de Canarias , Vía Láctea s/n, E-38205 La Laguna, Tenerife, Spain
15. Departamento de Astrofísica, Universidad de La Laguna , E-38200 La Laguna, Tenerife, Spain
16. INAF – Astronomical Observatory of Capodimonte , Salita Moiariello 16, 80131, Naples, Italy
17. Departamento de Física de la Tierra y Astrofísica, Instituto de Física de Partículas y del Cosmos , IPARCOS. Universidad Complutense de Madrid (UCM), 28040, Madrid, Spain
18. Centre for Space Research, North–West University , Potchefstroom 2520, South Africa
19. Center for Computational Sciences, University of Tsukuba , Ten-nodai, 1-1-1 Tsukuba, Ibaraki 305-8577, Japan
20. Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117 Heidelberg, Germany
21. Centre for Extragalactic Astronomy, University of Durham , Stockton Road, Durham DH1 3LE, United Kingdom
22. Department of Astrophysics, University of Vienna , Türkenschanzstraße 17, A-1180 Vienna, Austria