Abstract
CYG X-1 exhibited three pronounced X-ray intensity increases during 1975. The last of these, unlike the previous two, has not rapidly decayed back to its pre-increase value. Such a persistently high emission level from Cyg X-1 has not been observed since the source ‘transition’ in 19711.
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HOLT, S., KALUZIENSKI, L., BOLDT, E. et al. A return to the pre-1971 intensity level and a 5.6-d modulation for Cyg X-1. Nature 261, 213–215 (1976). https://doi.org/10.1038/261213a0
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DOI: https://doi.org/10.1038/261213a0
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