Affiliation: | Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544, USA,;N. Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw, Poland,;Department of Physics, University of Leicester, University Road, Leicester LE1 7RH,;Lab for High Energy Astrophysics, NASA/GSFC, Greenbelt, MD 20771, USA,;Astronomy Department, University of Maryland, College Park, MD 20742, USA,;E. O. Hulburt Center for Space Research, Naval Research Lab, Washington, DC 20375, USA |