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The integral high-energy cut-off distribution of type 1 active galactic nuclei

The integral high-energy cut-off distribution of type 1 active galactic nuclei
The integral high-energy cut-off distribution of type 1 active galactic nuclei
In this Letter we present the primary continuum parameters, the photon index ?, and the high-energy cut-off E c of 41 type-1 Seyfert galaxies extracted from the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) complete sample of active galactic nuclei (AGNs). We performed broadband (0.3-100 keV) spectral analysis by simultaneously fitting the soft and hard X-ray spectra obtained by XMM and INTEGRAL/IBIS-Swift/BAT, respectively, in order to investigate the general properties of these parameters, in particular their distribution and mean values. We find a mean photon index of 1.73 with a standard deviation of 0.17 and a mean high-energy cut-off of 128 keV with a standard deviation of 46 keV for the whole sample. This is the first time that the cut-off energy is constrained in such a large number of AGNs. We have 26 measurements of the cut-off, which corresponds to 63% of the entire sample, distributed between 50 and 200 keV. There are a further 11 lower limits mostly below 300 keV. Using the main parameters of the primary continuum, we have been able to obtain the actual physical parameters of the Comptonizing region, i.e., the plasma temperature kT e from 20 to 100 keV and the optical depth ? < 4. Finally, with the high signal-to-noise ratio spectra starting to come from NuSTAR it will soon be possible to better constrain the cut-off values in many AGNs, allowing the determination of more physical models and thus better understand the continuum emission and geometry of the region surrounding black holes.
1-6
Malizia, A.
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Molina, M.
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Bassani, L.
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Stephen, J.B.
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Bazzano, A.
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Ubertini, P.
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Bird, A.J.
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Malizia, A.
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Molina, M.
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Bassani, L.
07e5602c-f97e-4334-a0fa-c2212431a61a
Stephen, J.B.
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Bazzano, A.
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Ubertini, P.
7035748e-152c-473e-8766-a2fa3ac49fcb
Bird, A.J.
045ee141-4720-46fd-a412-5aa848a91b32

Malizia, A., Molina, M., Bassani, L., Stephen, J.B., Bazzano, A., Ubertini, P. and Bird, A.J. (2014) The integral high-energy cut-off distribution of type 1 active galactic nuclei. The Astrophysical Journal Letters, 782 (2), 1-6, [L25]. (doi:10.1088/2041-8205/782/2/L25).

Record type: Article

Abstract

In this Letter we present the primary continuum parameters, the photon index ?, and the high-energy cut-off E c of 41 type-1 Seyfert galaxies extracted from the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) complete sample of active galactic nuclei (AGNs). We performed broadband (0.3-100 keV) spectral analysis by simultaneously fitting the soft and hard X-ray spectra obtained by XMM and INTEGRAL/IBIS-Swift/BAT, respectively, in order to investigate the general properties of these parameters, in particular their distribution and mean values. We find a mean photon index of 1.73 with a standard deviation of 0.17 and a mean high-energy cut-off of 128 keV with a standard deviation of 46 keV for the whole sample. This is the first time that the cut-off energy is constrained in such a large number of AGNs. We have 26 measurements of the cut-off, which corresponds to 63% of the entire sample, distributed between 50 and 200 keV. There are a further 11 lower limits mostly below 300 keV. Using the main parameters of the primary continuum, we have been able to obtain the actual physical parameters of the Comptonizing region, i.e., the plasma temperature kT e from 20 to 100 keV and the optical depth ? < 4. Finally, with the high signal-to-noise ratio spectra starting to come from NuSTAR it will soon be possible to better constrain the cut-off values in many AGNs, allowing the determination of more physical models and thus better understand the continuum emission and geometry of the region surrounding black holes.

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Accepted/In Press date: 14 January 2014
e-pub ahead of print date: 3 February 2014
Published date: 20 February 2014
Organisations: Astronomy Group

Identifiers

Local EPrints ID: 401051
URI: http://eprints.soton.ac.uk/id/eprint/401051
PURE UUID: 2dcc0079-fe8e-4da9-92ac-aaa89e92228c
ORCID for A.J. Bird: ORCID iD orcid.org/0000-0002-6888-8937

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Date deposited: 04 Oct 2016 08:54
Last modified: 16 Nov 2021 02:35

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Contributors

Author: A. Malizia
Author: M. Molina
Author: L. Bassani
Author: J.B. Stephen
Author: A. Bazzano
Author: P. Ubertini
Author: A.J. Bird ORCID iD

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