ESA Science & Technology - High-energy gamma-ray and hard X-ray observations of CYG X-3

Publication date: 15 March 1987

Authors: Hermsen, W., et al.

Journal: Astronomy and Astrophysics
Volume: 175
Issue: 1-2
Page: 147-150
Year: 1987

Copyright: European Southern Observatory

COS-B viewed the Cyg X-3 region seven times between November, 1975, and February, 1982; a search for steady gamma-ray emission pulsed at the characteristic 4.8-hour period did not reveal its source. Leiden-MIT balloon experiment observations of Cyg X-3 in May, 1979 show the 4.8-hour modulation with sinusoidal light curve and modulation depth of 0.30, for energies of up to about 140 keV. The strong variability of Cyg X-3 over more than one order of magnitude at energies below 20 keV does not emerge in the data collected at hard X-ray energies.