1. Department of Physics, University of Surrey, Guildford GU2 7XH, UK
2. Institute for Astronomy, University of Hawai‘i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
3. Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona, Spain
4. ICREA, Pg. Lluis Companys 23, E-08010 Barcelona, Spain
5. Kapteyn Astronomical Institute, University of Groningen, Postbus 800, NL-9700AV Groningen, the Netherlands
6. National Research Council, Herzberg Astronomy & Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada
7. INAF Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy
8. European Southern Observatory, Karl-Schwarzschild-Str 2, D-85748 Garching, Germany