1. Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife, Spain
2. Departamento de Astrofísica, Univ. de La Laguna, E-38206 La Laguna, Tenerife, Spain
3. SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, NL-3584CA Utrecht, The Netherlands
4. School of Physics and Astronomy, Jodrell Bank Centre for Astrophysics, The University of Manchester, Manchester M13 9PL, UK
5. Department of Physics, Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
6. Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
7. Department of Astrophysics/IMAPP, Radboud University, PO Box 9010, NL-6500GL Nijmegen, the Netherlands
8. Departament de Física, EEBE, Universitat Politècnica de Catalunya, c/ Eduard Maristany 10, E-08019 Barcelona, Spain
9. Institute of Space Studies of Catalonia (IEEC), E-08034 Barcelona, Spain
10. Department of Physics, University of Alberta, CCIS 4-181, Edmonton AB T6G 2E1, Canada
11. Universidad Internacional de Valencia (VIU), E-46002 Valencia, Spain
12. Astronomical Institute, Academy of Sciences of the Czech Republic, Bocn̂í II 1401, CZ-141 00 Prague, Czech Republic
13. Instituto de Astrofísica de Andalucía (CSIC), E-18008 Granada, Spain
14. Unidad Asociada Departamento de Ingeniería de Sistemas y Automática, Universidad de Málaga, E-29071 Málaga, Spain
15. Isaac Newton Group of Telescopes, Apto. 321, E-38700 Santa Cruz de la Palma, Canary Islands, Spain