The broad-band XMM-Newton and INTEGRAL spectra of bright type 1 Seyfert galaxies
de Rosa, A.; Walter, R.; Bird, A. J.; Fiocchi, M.; Ubertini, P.; Malizia, A.; Bassani, L.; Dean, A. J.; Panessa, F.; Molina, M.
Italy, Spain, United Kingdom, Switzerland
Abstract
Aims: 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 (< Γ > = 1.7 ± 0.2) is consistent, within errors, with the canonical spectral slope often observed in AGN although the photon index distribution peaks in our case at flat Γ (~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.