1. Max-Planck-Institut für extraterrestrische Physik , Gießenbachstraße 1, D-85748 Garching, Germany
2. Institute of Astronomy , Madingley Road, Cambridge CB3 0HA, UK
3. INAF – IASF Palermo , Via U La Malfa 153, I-90146 Palermo, Italy
4. Department of Astronomy, University of Geneva , Ch. d’Ecogia 16, CH-1290 Versoix, Switzerland
5. School of Physics & Astronomy, University of Nottingham , University Park, Nottingham NG7 2RD, UK
6. Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA) , Kanagawa 252-5210, Japan
7. Department of Physics and Astronomy, University of Alabama in Huntsville , Huntsville, AL 35899, USA
8. Harvard-Smithsonian Center for Astrophysics , 60 Garden Street, Cambridge, MA 02138, USA