1. Hamburger Sternwarte, University of Hamburg , Gojenbergsweg 112, D-21029 Hamburg, Germany
2. Max-Planck-Institut für extraterrestrische Physik , Giessenbachstraße 1, D-85748 Garching, Germany
3. Department of Physics and Astronomy, Bologna University - Via Zamboni , 33, I-40126 Bologna, Italy
4. INAF - Istituto di Radioastronomia , I-40129 Bologna, Italy
5. Netherlands Institute for Radio Astronomy (ASTRON) , P.O. Box 2, NL-7990 AA Dwingeloo, the Netherlands
6. Leiden Observatory, Leiden University , PO Box 9513, NL-2300 RA Leiden, the Netherlands
7. School of Physical Sciences and Centre for Astrophysics & Relativity, Dublin City University , Glasnevin, D09 W6Y4, Ireland
8. ICRAR, The University of Western Australia , 35 Stirling Hwy, 6009 Crawley, Australia