Search

We present results on the geometry and location of the X‐ray narrow line region in NGC 5548 obtained by analyzing multiple high‐resolution X‐ray grating observation covering an almost 10 year period. Variability combined with the high spectral resolution of the gratings aboard Chandra and XMM‐Newton are key for obtaining these results. The goal is to extend this method to other type 1 AGN as well.

We present some results of the deepest extragalactic survey performed by the INTEGRAL satellite. The fraction of very absorbed AGN is quite large. The sharp decrease in the absorption fraction with X-ray luminosity observed at lower-energy X-rays is not observed. The current lack of truly Compton-thick objects, with an upper limit of 14% to the size of this population, is just compatible with recent modeling of the cosmic X-ray background. We also study the prospects for a future hard X-ray serendipitous survey with Simbol-X. We show that Simbol-X will easily detect a large number of serendipitous AGN, allowing us to study the evolution of AGN up to redshifts about 2, opening the door to the cosmological study of hard X-ray selected AGN, which is barely possible with existing satellites like Swift and INTEGRAL., Proceedings of the 2nd Simbol-X symposium: "Simbol-X - Focusing on the Hard X-ray Universe", AIP Conf. Proc. Series, 4 pages. Fixed affiliations

We present a power spectral analysis survey of 24 active galactic nuclei (AGN). We combine X‐ray observations to produce a power spectrum covering a broad range of Fourier frequencies and fit the power spectrum of each AGN using a single‐bend power‐law model. Using the resultant bend time‐scales of 18 AGN, and of the Galactic black hole X‐ray binaries Cyg X‐1 and GRS1915+105, we present a plot of observed bend time‐scales versus the predicted bend time‐scales determined from published masses and bolometric luminosities. The results confirm our previously proposed scaling relation of bend time‐scale with mass divided by accretion rate. All work presented herein can be found in Summons et al. [1].

In this paper we review the very large contribution made by RXTE to our understanding of Active Galaxies (AGN). We discuss the relationship between AGN and Galactic Black Hole X‐ray binary systems (GBHs) and show, by comparison of their powerspectral densities (PSDs) that some AGN are the equivalent of GBHs in their ‘high’ state, rather than in their ‘low’ state as has previously been assumed. We plot the timescale at which the PSD slope steepens from −1 to −2 against the black hole mass for a sample of AGN, and for Cyg X‐1 in its high and low states. We find it is not possible to fit all AGN to the same linear scaling of break timescale with black hole mass. However broad line AGN are consistent with a linear scaling of break timescale with mass from Cyg X‐1 in its low state and NLS1 galaxies scale better with Cyg X‐1 in its high state, although there is an exception, NGC3227. We suggest that the relationship between black hole mass and break timescale is a function of another underlying parameter which may be accretion rate or black hole spin or, probably, both. We examine X‐ray spectral variability and show how simple ‘flux‐flux’ plots can distinguish between ‘two‐component’ and ‘spectral pivoting’ models. We also examine the relationship between the X‐ray emission and that in other wavebands. In the case of X‐ray/optical variability we show how cooler discs in AGN with larger mass black holes lead to greater proximity of the X‐ray and optical emission regions and hence to more highly correlated variability. The very large amplitude of optical variability then rules out reprocessing as the origin of the optical emission. We show how the radio emission in NGC 4051 is strongly correlated with the X‐ray emission, implying some contribution to the X‐ray emission from a jet for which there is some evidence in radio images. We point out, however, that we have only studied in detail the X‐ray variability of a handful of AGN. There is a strong requirement to extend such studies to unbiased samples of many hundreds of AGN and so a strong need for a very sensitive (

We have monitored the Seyfert galaxies NGC 4051 and NGC 5506 with RXTE for the last 3 years. During this time, we have witnessed large variations in the X-ray flux of both sources, coupled to spectral variability. In both objects the 6.4 keV iron fluorescence line and the reflection hump are relatively stronger during fainter states of the X-ray source. These variations can be simply explained if there are not one, but two reflection components contributing to the X-ray spectrum of these sources: a reflection component which scales linearly with the primary continuum flux (as expected from the accretion disk), and a constant component due to reflection off distant cold matter.