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.


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    Titel :

    Hard X-ray observations of Cygnus X−1 with the Mifraso telescope


    Beteiligte:
    Perotti, F. (Autor:in) / Bassani, L. (Autor:in) / Bazzano, A. (Autor:in) / Court, A. (Autor:in) / Dean, A.J. (Autor:in) / Dipper, N. (Autor:in) / Lewis, R. (Autor:in) / Quadrini, E. (Autor:in) / Stephen, J.B. (Autor:in) / Ubertini, P. (Autor:in)

    Erschienen in:

    Advances in Space Research ; 11 , 8 ; 101-105


    Erscheinungsdatum :

    01.01.1991


    Format / Umfang :

    5 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch



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