The INTEGRAL Complete Sample of Type 1 AGN

Abstract

We present the broad-band X-ray characteristics of a complete sample of 36 type 1 AGN, detected by INTEGRAL in the 20-40 keV band above the 5.5 σ level. We performed the broad-band (1-110 keV) spectral analysis using INTEGRAL/Swift/BAT observations together with XMM-Newton, Chandra, ASCA and Swift/XRT data. We also present the general average properties of the sample, i.e. the distribution of photon indices, high energy cut-offs, reflection fractions and absorption properties, together with an in-depth analysis of their parameter space. We find that the average Seyfert 1 power law has an index of 1.7 with a dispersion of 0.2. The mean cut-off energy is at around 100 keV, with most objects displaying E c in the range 50-150 keV; the average amount of Compton reflection is 1.5 with a typical dispersion of 0.7. We do not find any convincing correlation between the various parameters, an indication that our analysis is not strongly dependent by the interplay between them. Finally, we investigate how the results presented in this work fit into current frameworks for AGN spectral modeling and Cosmic Diffuse X-ray Background synthesis models.

INTEGRAL: Science Highlights and Future Prospects

“…This is a confirmation that INTEGRAL is reaching a sensitivity good enough to firmly detect the high energy cut-off of at least the closest Seyferts and brightest Blazars (Panessa et al, 2011). Broad-band spectral analysis of more than 100 AGN has shown that their high-energy radiation is due to thermal Comptonisation of soft photons by a plasma surrounding the central black hole, which is mildly relativistic and has a low optical depth (Molina et al, 2009;Beckmann et al, 2009). The latest INTEGRAL catalogue (Bird et al, 2010) has significantly increased the number of these objects detected above 10 keV to more than 250, spanning a large range in redshift (0≤z≤3.7) and luminosities (10 42 -10 48 erg/s) ( Fig.…”

Hot Coronae in Local AGN: Present Status and Future Perspectives

“…Some of these works showed that there is a degeneracy between the cutoff energy and the Compton reflection fraction (commonly indicated as R) [25] while average values of Γ = 1.76 +0. 22 −0.24 , E c = 106 +186 −61 keV, R = 1.5 +1.5 −1.0 are retrieved when only Type 1 AGN are taken into account [22]. A recent work with Swift-BAT on 838 AGN confirmed these results, with cutoff energies in the range 50-300 keV for the whole non-blazar AGN sample [26].…”

“…BeppoSAX was the first satellite which had been used for this kind of studies [8,20] showing a relation between the photon index of the primary power law and the high energy curvature [21], likely due to the limited sensitivity of the instrument at high energies. With the advent of INTEGRAL many other works described the high energy behavior of type 1 and type 2 AGN, in particular when XMM-Newton, Suzaku or Chandra were used to cover the energy band below 10 keV [22][23][24][25]. Some of these works showed that there is a degeneracy between the cutoff energy and the Compton reflection fraction (commonly indicated as R) [25] while average values of Γ = 1.76 +0.…”

“…These models assume a geometry in which the corona is extended above the accretion disk and distributed as a slab or a sphere (Figure 1, panels (a) and (b), respectively). In a slab configuration the range of optical depth values is τ = 0.01-2.5, with a kT e = 10-300 keV and these parameters do not correlate with physical quantities of the system such as the black hole mass, the luminosity or the accretion rate [3], as previously discussed in the past using INTEGRAL [22]. Taking into account both slab and spherical geometries the only statistically significant correlation is between the optical depth and the electron temperature, following the relations presented in [3]: SLAB : log(kT e ) = (−0.7 ± 0.1) log(τ) + (1.60 ± 0.06)…”

Water maser and hard X-ray emission in AGN

“…The X-ray and hard X-ray properties of the sample as a whole and, separately, of the different Seyfert classes which made up the sample, have been studied in detail for a proper determination of the column density and the unabsorbed flux (i.e. type1: [10]; type 2: [2]; NLSy1: [11]). It has been shown, from the column density distribution of the sample, that the fraction of absorbed (N H > 10 22 cm −2 ) objects is nearly 40%.…”