Affiliation: | School of Physics and Astronomy, Southampton University, Southampton SO17 1BJ;NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA;Universities Space Research Association, 10211 Wincopin Circle, Suite 500, Columbia, MD 21044-3432, USA;Department of Astronomy, University of Maryland, College Park, MD 20742, USA;Harvard–Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA |