1. Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK
2. Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife, Spain
3. Dpto. Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
4. Aix Marseille Univ, CNRS, CNES, LAM 13013 Marseille, France
5. ENS de Lyon, CNRS, Centre de Recherche en Astrophysique de Lyon UMR5574, Université de Lyon, F-69230 Saint-Genis-Laval, France
6. Sterrewacht Leiden, Universiteit Leiden, NL-2300 RA Leiden, the Netherlands
7. School of Sciences, European University Cyprus, Diogenes street, Engomi, 1516 Nicosia, Cyprus
8. Department of Physics and Astronomy, University of Hawaii, 2505 Correa Road, Honolulu, HI 96822, USA
9. Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822, USA
10. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
11. National Centre for Nuclear Research, ul. Hoża 69, PL-00-681 Warszawa, Poland
12. Department of Astronomy, University of Cape Town, 7701 Rondebosch, Cape Town, South Africa
13. Department of Physics and Astronomy, University of the Western Cape, 7535 Bellville, Cape Town, South Africa
14. INAF – Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna, Italy