Abstract During a balloon flight in July 1987 of the MIFRASO hard X-ray telescope, a single drift-scan observation was performed to survey a region of the sky containing the galactic black hole candidate Cyg X−1. In about 900 seconds of on-source useful data, Cyg X−1 was detected in the energy range 15–300 keV with a high degree of statistical significance. The photon spectrum is well described by either a single power law with a photon index of α = 1.9 ± 0.07 or a Comptonized model characterized by an electron temperature of kT = 56 ± 9 keV and an optical depth of τ = 2.3 ± 0.3. The measured flux values suggest that during the MIFRASO observation the source was in the so called ‘superlow’ state.
Hard X-ray observations of Cygnus X−1 with the Mifraso telescope
Advances in Space Research ; 11 , 8 ; 101-105
01.01.1991
5 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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