1. University of California Observatories, 1156 High Street, Santa Cruz, CA 95064, USA
2. Max-Planck Institut für Astronomie, Konigstuhl 17, D-69117 Heidelberg, Germany
3. Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
4. Departamento de Astrofísica, Universidad de La Laguna, E-38205 La Laguna, Tenerife, Spain
5. INAF - Osservatorio Astronomico di Capodimonte, Napoli, Italy
6. Max-Planck Institut für Astrophysics, Karl-Schwarzschild-Str. 1, D-85741 Garching, Germany
7. European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching b. München, Germany