The broad-band XMM-Newton and INTEGRAL spectra of bright type 1 Seyfert galaxies

Panessa, F., Bassani, L., De Rosa, A., Bird, A.J., Dean, A.J., Fiocchi, M., Malizia, A., Molina, M., Ubertini, P. and Walter, R. (2008) The broad-band XMM-Newton and INTEGRAL spectra of bright type 1 Seyfert galaxies. Astronomy & Astrophysics, 483 (1), 151-160. (doi:10.1051/0004-6361:20078657).

Abstract

Aim: the 0.5-150 keV broad-band spectra of a sample of nine bright type 1 Seyfert galaxies are analyzed here. These sources have been discovered/detected by INTEGRAL and subsequently observed with XMM-Newton for the first time with high sensitivity below 10 keV. The sample, although small, is representative of the population of type 1 AGN which are now being observed above 20 keV.

Methods: the intrinsic continuum has been modeled using three different parameterizations: a power-law model, an exponential cut-off power-law and an exponential cut-off power-law with a Compton reflection component. In each model the presence of intrinsic absorption, a soft component and emission line reprocessing features has also been tested.

Results: a simple power-law model is a statistically good description of most of the spectra presented here; an FeK line, fully and/or partial covering absorption and a soft spectral component are detected in the majority of the sample sources. The average photon index ( ) is consistent, within errors, with the canonical spectral slope often observed in AGN although the photon index distribution peaks in our case at flat (~1.5) values. For four sources, we find a significantly improved fit when the power-law is exponentially cut-off at an energy which is constrained to be below ~150 keV. The Compton reflection parameter could be estimated in only two objects of the sample and in both cases is found to be R > 1.

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Contributors

Author: A.J. Bird

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