Institution: | Departamento de Astrofísica, Facultad de Físicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain; Pennsylvania State University, Department of Astronomy &Astrophysics, 525 Davey Lab, University Park, PA 16802, USA; Harvard-Smithsonian Center for Astrophysics, MS-58, 60 Garden Street, Cambridge, MA 02138, USA; School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS; Institute for Astronomy, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna, Austria |