Affiliation: | Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT;MIT Centre for Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA;SRON, the National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, the Netherlands;Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA |