Institution: | Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich, Switzerland;Astronomy Department, University of Washington, Seattle, WA 98195-1580, USA;Institut für Astronomie, ETH Zürich, CH-8093 Zürich, Switzerland;Institut für Astrophysik, Leopold-Franzens Universität Innsbruck, A-6020 Innsbruck, Austria |