1. Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
2. School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
3. Astrophysics Research Group, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, United Kingdom
4. Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany
5. Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany
6. Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
7. Department of Astronomy, San Diego State University, San Diego, CA 92182, USA
8. Department of Physics and Astronomy, University of Victoria, PO Box 1700 STN CSC, Victoria, B.C., V8W 2Y2, Canada
9. Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
10. Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706, USA
11. McDonald Observatory, University of Texas, HC75 Box 1337-L Fort Davis, TX 79734, USA
12. Department of Astronomy and Theoretical Physics, Lund Observatory, Lund University, Box 43, SE-221 00 Lund, Sweden
13. Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006, Australia
14. School of Physics, The University of New South Wales, Sydney NSW 2052, Australia
15. Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
16. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA