Hard X-ray observations of Cygnus X−1 with the Mifraso telescope
| Autor: | A.J. Court, P. Ubertini, J. B. Stephen, A. Bazzano, F. Perotti, A. J. Dean, E. M. Quadrini, R.A. Lewis, Nigel Dipper, Loredana Bassani |
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| Rok vydání: | 1991 |
| Předmět: |
Physics
Atmospheric Science Photon Astrophysics::High Energy Astrophysical Phenomena Aerospace Engineering Astronomy Astronomy and Astrophysics X-ray telescope Astrophysics::Cosmology and Extragalactic Astrophysics Gamma-ray astronomy Astrophysics Light curve law.invention Telescope Black hole Geophysics Space and Planetary Science law Optical depth (astrophysics) Binary star General Earth and Planetary Sciences |
| Zdroj: | Advances in Space Research. 11:101-105 |
| ISSN: | 0273-1177 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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