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Paper: X-ray Variability of NGC 4051 AGN with RXTE and XMM
Volume: 290, Active Galactic Nuclei: from Central Engine to Host Galaxy
Page: 111
Authors: McHardy, I.; Uttley, P.; Mason, K.; Page, M.
Abstract: We present the results of 6 years of intensive monitoring on ∼few daily timescales of a sample of AGN with RXTE together with, in some cases, continuous ∼few hundred ksec observations with ASCA and XMM. These observations provide the best data so far obtained on the long and short timescale X-ray variability of AGN and, via their powerspectra (PSDs), enable us to compare AGN with galactic black hole candidates (GBHs). The XMM observations probe shorter timescales than ever before and, in NGC4051, show steepening of the PSD at ∼few hundred sec to a slope of -2.7, thereby removing previous fears that mass-energy conversion efficiency might exceed 40%. In some cases AGN PSDs are more similar to those of `high' than `low' state GBHs. The XMM observations also clearly show a hardening of high frequency PSD slope with increasing photon energy, as seen in GBHs and commonly described by Comptonisation models. We compare the AGN black hole masses derived from reverberation studies with those derived by comparing AGN PSDs, in high and low state models, with those of GBHs.
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