Affiliation: | Department of Astronomy and Space Science, College of Natural Science and Institute for Basic Science Research, Chungbuk National University, Cheongju 361-763, Korea;Korea Astronomy Observatory, Daejon 305-348, Korea;Optical Science Laboratory, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT;Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA |