Ultraviolet Study of U1341-CYGNI = CYGNUS-X-2 - Observations of an Accretion Disk
Maraschi, L.; Tanzi, E. G.; Chiappetti, L.; Treves, A.
Italy
Abstract
Observations of Cyg X-2 with the International Ultraviolet Explorer in the range 1200-3000 A are discussed with particular reference to the continuum. The dereddened UV spectrum indicates the presence of a contribution from a hot region of small area which is naturally interpreted as an X-ray heated accretion disk. Assuming an average X-ray luminosity of Lx equals 6.4 x 10 to the 37th erg/s, the solid angle subtended by the disk is estimated at l sterad from the ratio of the disk luminosity L disk equals L2 to Lx.