Showing papers by "Maria Santos-Lleo published in 2007"
TL;DR: In this article, the authors present the results of the analysis of the hard band XMM-Newton spectra of the luminous, $L 2{-}10~{\rm keV}}\sim3.4\times10^{45}$/s, radio-quiet quasar, E 1821+643.
Abstract: We present the results of the analysis of the hard band XMM-Newton spectra of the luminous, $L_{2{-}10~{\rm keV}}\sim3.4\times10^{45}$ erg/s, radio-quiet quasar, E 1821+643 . Two emission features were observed in the 6–7 keV rest frame band, confirming previous Chandra detection of these structures. We interpret these features as two single emission lines, one consistent with the neutral Fe K α line at 6.4 keV and the other most likely due to FeXXVI. If related to the quasar, the high-energy emission line should originate in highly ionised matter, i.e. the accretion disc or the clouds of the emission line regions. Alternatively, it may be related to the intergalactic medium of the rich galaxy cluster in which E 1821+643 is embedded. A composite broad emission line in combination with an absorption line model, however, also fits the data well. We discuss the possible physical interpretations of the origin of these features.
19 citations
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TL;DR: In this article, an XMM-Newton systematic analysis of a sample of nine Seyfert 1 galaxies was carried out and the results indicated that these AGN are viewed with an inclination comparable with the torus opening angle, which is consistent with this scenario and, taking advantage of this favourable geometrical condition, the physical properties and the distribution of the circumnuclear gas in these sources were investigated in detail.
Abstract: We present the results on an XMM-Newton systematic analysis of a sample of nine Seyfert 1 galaxies. When observed in polarised light, the spectra of the selected sources are similar to those of Seyfert 2 galaxies. This peculiarity strongly suggests that these AGN are viewed with an inclination comparable with the torus opening angle. Our results are consistent with this scenario and, taking advantage of this favourable geometrical condition, we were able to investigate in detail the physical properties and the distribution of the circumnuclear gas in these sources.
3 citations
17 Aug 2007
TL;DR: In this article, the authors carried out a systematic search for narrow features using spectra of bright type 1 AGNs available in the XMM•Newton archive and estimated the significance of the features through Monte Carlo simulations.
Abstract: The detection of X‐ray narrow spectral features in the 5–7 keV band is becoming increasingly more common in AGN observations, thanks to the capabilities of current X‐ray satellites. Such lines, both in emission and in absorption, are mostly interpreted as arising from Iron atoms. When observed with some displacement from their rest frame position, these lines carry the potential to study the motion of circumnuclear gas in AGN, providing a diagnostic of the effects of the gravitational field of the central black hole. These narrow features have been often found with marginal statistical significance. We are carrying on a systematic search for narrow features using spectra of bright type1 AGNs available in the XMM‐Newton archive. The aim of this work is to characterise the occurrence of the narrow features phenomenon on a large sample of objects and to estimate the significance of the features through Monte Carlo simulations. The project and preliminary results are presented.
2 citations