Abstract
EXTENDED spectral measurements are now available at more than one time epoch for the powerful Monoceros transient, A0620–00, discovered by Elvis et al.1, and the binary source Cyg X-l. We here point out a basic similarity in the unusual spectral time variations of these sources. Both are black-hole candidates, Cyg X-l by virtue of its orbital dynamics and A0620–00 as suggested by arguments based on the Eddington limit1 and distance estimates of the optical counterpart. Thus the X-ray emission mechanism could be common.
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References
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COE, M., ENGEL, A. & QUENBY, J. Anti-correlated hard and soft X-ray intensity variations of the black-hole candidates Cyg X-1 and A0620—00. Nature 259, 544–546 (1976). https://doi.org/10.1038/259544a0
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DOI: https://doi.org/10.1038/259544a0
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