Institution: | aIsaac Newton Group of Telescopes, Apartado de Correos 321, E-38700 Santa Cruz de la Palma, Spain;bLeiden Observatory, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands;cDepartment of Physics, University of Durham, South Road, Durham DH1 3LE, United Kingdom;dNetherlands Foundation for Research in Astronomy, P.O. Box 2, 7990 AA Dwingeloo, The Netherlands |