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arXiv · astro-ph/0301216

Correlated long-term optical and X-ray variations in NGC 5548

Phil Uttley·Rick Edelson·Ian McHardy·Bradley M. Peterson·Alex Markowitz
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Abstract

We combine the long-term optical light curve of the Seyfert 1 galaxy NGC5548 with the X-ray light curve measured by the Rossi X-ray Timing Explorer over 6 years, to determine the relationship between the optical and X-ray continua. The X-ray light curve is strongly correlated with the optical light curve on long (~year) time-scales. The amplitude of the long-term optical variability in NGC5548 is larger than that of the X-ray variability (after accounting for the host galaxy contribution), implying that X-ray reprocessing is not the main source of the optical/X-ray correlation. The correlated X-ray and optical variations in NGC5548 may be caused by instabilities in the inner part of the accretion flow, where both the X-ray and optical emission regions may be located.

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Phil Uttley, Rick Edelson, Ian McHardy, Bradley M. Peterson, Alex Markowitz. 2003-01-13. Correlated long-term optical and X-ray variations in NGC 5548. https://doi.org/10.1086/373887

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