NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-07-15 T20:13:42 PDT
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For refcode 2007MNRAS.374.1290G:
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NED Abstract

Copyright by Royal Astronomical Society. 2007MNRAS.374.1290G On the origin of soft X-rays in obscured AGN: answers from high-resolution spectroscopy with XMM-Newton Matteo Guainazzi and Stefano Bianchi Abstract. We present results of a high-resolution soft X-ray (0.2-2 keV) spectroscopic study of a sample of 69 nearby obscured active galactic nuclei (AGNs) observed with the reflection grating spectrometer (RGS) onboard XMM-Newton. This is the largest sample ever studied with this technique so far. The main conclusions of our study can be summarized as follows: (i) narrow radiative recombination continua are detected in about 36 per cent of the objects in our sample (in 26 per cent their intrinsic width is <=10 eV); (II) higher order transitions are generally enhanced with respect to pure photoionization, indicating that resonant scattering plays an important role in the ionization/excitation balance. These results support the scenario, whereby the active nucleus is responsible for the X-ray 'soft excess' almost ubiquitously observed in nearby obscured AGNs via photoionization of circumnuclear gas. They confirm on a statistical basis the conclusions drawn from the detailed study of the brightest spectra in the sample. Furthermore, we propose a criterion to statistically discriminate between AGN-photoionized sources and starburst galaxies, based on intensity of the forbidden component of the O VII He{alpha} triplet (once normalized to the O VIII Ly{alpha}) coupled with the integrated luminosity in He- and H-like oxygen lines. Key words: galaxies: active, galaxies: nuclei, galaxies: Seyfert, X-rays: galaxies
Retrieve 69 NED objects in this reference.
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