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arXiv · astro-ph/9912103

Simultaneous EUV and X-ray variability of NGC 4051

P. Uttley·I. M. McHardy·I. E. Papadakis·I. Cagnoni·A. Fruscione
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Abstract

We present a flux variability study of simultaneous RXTE and EUVE observations of the highly variable Seyfert galaxy NGC4051. We find a strong correlation between variability in the EUV and medium energy X-ray bands,indicating that both are sampling the same power-law continuum. The lag between the two bands is less than 20 ks and, depending on model assumptions, may be <1 ks. We examine the consequences of such a small lag in the context of simple Comptonisation models for the production of the power-law continuum. A lag of <1 ks implies that the size of the Comptonising region is less than 20 Schwarzschild radii for a black hole of mass >1E6 solar masses.

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P. Uttley, I. M. McHardy, I. E. Papadakis, I. Cagnoni, A. Fruscione. 1999-12-06. Simultaneous EUV and X-ray variability of NGC 4051. https://doi.org/10.1046/j.1365-8711.2000.03266.x

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