The broad-band X-ray spectrum of the Seyfert 1 galaxy, MCG 8-11-11 - Astrophysics > Astrophysics of GalaxiesReportar como inadecuado

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Abstract: We present a long 100 ks Suzaku observation of one of the X-ray brightestAGN, MCG+8-11-11. These data were complemented with the 54-month Swift BATspectrum, allowing us to perform a broad-band fit in the 0.6-150 keV range. Thefits performed in the 0.6-10 keV band give consistent results with respect to aprevious XMM-Newton observation, i.e. the lack of a soft excess, warmabsorption along the line of sight, a large Compton reflection component R~1and the absence of a relativistic component of the neutral iron K$\alpha$emission line. However, when the PIN and Swift BAT data are included, thereflection amount drops significantly R~0.2-0.3, and a relativistic iron lineis required, the latter confirmed by a phenomenological analysis in arestricted energy band 3-10 keV. When a self-consistent model is applied tothe whole broadband data, the observed reflection component appears to be allassociated to the relativistic component of the iron K$\alpha$ line. Theresulting scenario, though strongly model-dependent, requires that all thereprocessing spectral components from Compton-thick material must be associatedto the accretion disc, and no evidence for the classical pc-scale torus isfound. The narrow core of the neutral iron K$\alpha$ line is therefore producedin a Compton-thin material, like the BLR, similarly to what found in anotherSeyfert galaxy, NGC7213, but with the notable difference that MCG+8-11-11presents spectral signatures from an accretion disc. The very low accretionrate of NGC7213 could explain the lack of relativistic signatures in itsspectrum, but the absence of the torus in both sources is more difficult toexplain, since their luminosities are comparable, and their accretion rates arecompletely different.

Autor: Stefano Bianchi, Ilaria De Angelis, Giorgio Matt, Valentina La Parola, Alessandra De Rosa, Paola Grandi, Elena Jiménez Bailón,


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