Abstract
The Crimean Observatory group have detected γ rays from the direction of the X-ray source Cyg X-3 (refs 1–5): rays of energy 1012eV were observed using the atmospheric Cerenkov technique. Measurements with satellite-borne instruments in the 108eV region have shown effects from Cyg X-3 in one case6, but not in another7. Similarly, γ rays have been seen in some balloon flights8, but not in those of McKechnie et al.9 nor of White et al.10. A study using the atmospheric Cerenkov technique at 1011eV showed no effect11, though it has been shown to be compatible with the Crimean result4. We report here observations taken at Mount Hopkins Observatory, Arizona (altitude 2.3 km) in April, May and June 1980 using a similar system to that of Stepanian et al.3, which seem to confirm, at least qualitatively, the Crimean results.
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References
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Danaher, S., Fegan, D., Porter, N. et al. γ-Ray observations of Cygnus X-3 at energies of 1012eV. Nature 289, 568–569 (1981). https://doi.org/10.1038/289568a0
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DOI: https://doi.org/10.1038/289568a0
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