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Power density spectrum of NGC 5548 and the nature of its variability

B. Czerny·A. Schwarzenberg-Czerny·Z. Loska
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Abstract

We derive power density spectra in the optical and X-ray band in the timescale range from several years down to $\sim $ a day. We suggest that the optical power density spectrum consists of two separate components: long timescale variations and short timescale variations, with the dividing timescale around 100 days. The shape of the short timescale component is similar to X-ray power density spectrum which is consistent with the interpretation of short timescale optical variations being caused by X-ray reprocessing. We show that the observed optical long timescale variability is consistent with thermal pulsations of the accretion disc.

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B. Czerny, A. Schwarzenberg-Czerny, Z. Loska. 1998-10-14. Power density spectrum of NGC 5548 and the nature of its variability. https://doi.org/10.1046/j.1365-8711.1999.02196.x

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