Reflection in Seyfert Galaxies and the Unified Model of AGN

Abstract

We present a deep study of the average hard X-ray spectra of Seyfert galaxies. We analyzed all public INTEGRAL IBIS/ISGRI data available on all the 165 Seyfert galaxies detected at z<0.2. Our final sample consists of 44 Seyfert 1's, 29 Seyfert 1.5's, 78 Seyfert 2's, and 14 Narrow Line Seyfert 1's. We derived the average hard X-ray spectrum of each subsample in the 17-250keV energy range. All classes of Seyfert galaxies show on average the same nuclear continuum, as foreseen by the zeroth order unified model, with a cut-off energy of Ec>200keV, and a photon index of Gamma ~1.8. Compton-thin Seyfert 2's show a reflection component stronger than Seyfert 1's and Seyfert 1.5's. Most of this reflection is due to mildly obscured (10^23 cm^-2 < NH < 10^24 cm^-2) Seyfert 2's, which have a significantly stronger reflection component (R=2.2^{+4.5}_{-1.1}) than Seyfert 1's (R<=0.4), Seyfert 1.5's (R<= 0.4) and lightly obscured (NH < 10^23 cm^-2) Seyfert 2's (R<=0.5). This cannot be explained easily by the unified model. The absorber/reflector in mildly obscured Seyfert 2's might cover a large fraction of the X-ray source, and have clumps of Compton-thick material. The large reflection found in the spectrum of mildly obscured Seyfert 2's reduces the amount of Compton-thick objects needed to explain the peak of the cosmic X-ray background. Our results are consistent with the fraction of Compton-thick sources being ~10%. The spectra of Seyfert 2's with and without polarized broad lines do not show significant differences, the only difference between the two samples being the higher hard X-ray and bolometric luminosity of Seyfert 2's with polarized broad lines. The average hard X-ray spectrum of Narrow line Seyfert 1's is steeper than those of Seyfert 1's and Seyfert 1.5's, probably due to a lower energy of the cutoff.

19 pages, accepted for publication in Astronomy and Astrophysics, final version

References in corpus (26)

• The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era
• Three years Swift-BAT Survey of AGN: reconciling theory and observations?
• An XMM-Newton spectral survey of 12 micron selected galaxies. I. X-ray data
• Cosmic X-ray background and Earth albedo Spectra with Swift/BAT
• The Infrared Nuclear Emission of Seyfert Galaxies on Parsec Scales: Testing the Clumpy Torus models
• Testing the Unification Model for AGN in the Infrared: are the obscuring tori of Type 1 and 2 Seyferts different?
• Suzaku Observations of Active Galactic Nuclei Detected in the Swift/BAT Survey: Discovery of "New Type" of Buried Supermassive Black Holes
• Seyfert galaxies in the local Universe (z$\le$ 0.1): the average X-ray spectrum as seen by $BeppoSAX$
• Low-Luminosity Active Galactic Nuclei: Are They UV-Faint and Radio Loud?
• X-ray properties of an Unbiased Hard X-ray Detected Sample of AGN
• Calibration of [O IV] 26 micron as a Measure of Intrinsic AGN Luminosity
• A description of sources detected by INTEGRAL during the first 4 years of observations
• BAT X-ray Survey - III: X-ray Spectra and Statistical Properties
• Investigating on the nuclear obscuration in two types of Seyfert 2 galaxies
• Unveiling the nature of INTEGRAL objects through optical spectroscopy. VII. Identification of 20 Galactic and extragalactic hard X-ray sources
• Prevalence of High X-ray Obscuring Columns among AGN that Host H${}_2$O Masers
• First high energy observations of Narrow Line Seyfert 1s with INTEGRAL/IBIS
• Swift-XRT observation of 34 new INTEGRAL/IBIS AGNs: discovery of Compton thick and other peculiar sources
• Chandra Localizations and Spectra of INTEGRAL Sources in the Galactic Plane
• The broad-band XMM-Newton and INTEGRAL spectra of bright type 1 Seyfert galaxies
• Constraints on light bending and reflection from the hard X-ray background
• Swift Follow-up Observations of INTEGRAL Sources of Unknown Nature
• The AGN nature of 11 out of 12 Swift/RXTE unidentified sources through optical and X-ray spectroscopy
• A deep INTEGRAL hard X-ray survey of the 3C 273/Coma region
• IGR J16351-5806: another close by Compton-thick AGN
• The hard X-ray view of bright infrared galaxies

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