Affiliation: | Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes, MK7 6AA;UniversitéParis VII and Service d'Astrophysique, CE-Saclay, Orme des Merisiers, F-91 191 Gif-sur-Yvette, Cedex, France;ESO, Karl Schwarzschild Str. 2, D-85748 Garching bei München, Germany;INAF –Osservatorio Astronomico di Roma, Via Frascati 33, I-00040, Monteporzio Catone, Italy |