1. Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany
2. Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Mail H30, PO Box 218, Hawthorn, VIC 3122, Australia
3. Australian Research Council Centre of Excellence for All-Sky Astrophysics (CAASTRO), Mail H30, PO Box 218, Hawthorn, VIC 3122, Australia
4. Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK
5. Department of Physics, West Virginia University, White Hall, Morgantown, WV 26506, USA
6. University of Applied Sciences Bonn-Rhein-Sieg, Grantham-Allee 20, D-53757 Sankt Augustin, Germany