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The X-ray disc/wind degeneracy in AGN

The X-ray disc/wind degeneracy in AGN
The X-ray disc/wind degeneracy in AGN
Relativistic Fe K emission lines from accretion discs and from disc winds encode key information about black holes, and their accretion and feedback mechanisms. We show that these two processes can in principle produce indistinguishable line profiles, such that they cannot be disentangled spectrally. We argue that it is likely that in many cases both processes contribute to the net line profile, and their relative contributions cannot be constrained purely by Fe K spectroscopy. In almost all studies of Fe K emission to date, a single process (either disc reflection or wind Compton scattering) is assumed to dominate the total line profile. We demonstrate that fitting a single process emission model (pure reflection or pure wind) to a hybrid line profile results in large systematic biases in the estimates of key parameters, such as mass outflow rate and spin. We discuss various strategies to mitigate this effect, such as including high-energy data covering the Compton hump, and the implications for future X-ray missions.
accretion, accretion discs, black hole physics, galaxies: Active
1365-2966
551–572
Middleton, Matthew
f91b89d9-fd2e-42ec-aa99-1249f08a52ad
Parker, M.L.
0c6dda9e-1ea5-485c-a94c-135aca6339e8
Matzeu, G.A.
35f2b40d-1f1f-453a-90d5-408a4dbba3dd
Matthews, J. H.
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Dauser, T.
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Jiang, J.
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Joyce, A.M.
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Middleton, Matthew
f91b89d9-fd2e-42ec-aa99-1249f08a52ad
Parker, M.L.
0c6dda9e-1ea5-485c-a94c-135aca6339e8
Matzeu, G.A.
35f2b40d-1f1f-453a-90d5-408a4dbba3dd
Matthews, J. H.
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Dauser, T.
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Jiang, J.
2191608a-1675-4277-97de-ada0a707caa9
Joyce, A.M.
9b4db639-9ce3-4aae-b865-2d2def680bfa

Middleton, Matthew, Parker, M.L., Matzeu, G.A., Matthews, J. H., Dauser, T., Jiang, J. and Joyce, A.M. (2022) The X-ray disc/wind degeneracy in AGN. Monthly Notices of the Royal Astronomical Society, 513 (1), 551–572. (doi:10.1093/mnras/stac877).

Record type: Article

Abstract

Relativistic Fe K emission lines from accretion discs and from disc winds encode key information about black holes, and their accretion and feedback mechanisms. We show that these two processes can in principle produce indistinguishable line profiles, such that they cannot be disentangled spectrally. We argue that it is likely that in many cases both processes contribute to the net line profile, and their relative contributions cannot be constrained purely by Fe K spectroscopy. In almost all studies of Fe K emission to date, a single process (either disc reflection or wind Compton scattering) is assumed to dominate the total line profile. We demonstrate that fitting a single process emission model (pure reflection or pure wind) to a hybrid line profile results in large systematic biases in the estimates of key parameters, such as mass outflow rate and spin. We discuss various strategies to mitigate this effect, such as including high-energy data covering the Compton hump, and the implications for future X-ray missions.

Text
2203.14789 - Accepted Manuscript
Available under License Creative Commons Attribution.
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More information

Accepted/In Press date: 28 March 2022
e-pub ahead of print date: 31 March 2022
Published date: 1 June 2022
Additional Information: Publisher Copyright: © 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
Keywords: accretion, accretion discs, black hole physics, galaxies: Active

Identifiers

Local EPrints ID: 457493
URI: http://eprints.soton.ac.uk/id/eprint/457493
ISSN: 1365-2966
PURE UUID: 658a3d21-849a-4756-aecf-0fb4e9c4368f

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Date deposited: 09 Jun 2022 17:05
Last modified: 16 Mar 2024 17:33

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Contributors

Author: M.L. Parker
Author: G.A. Matzeu
Author: J. H. Matthews
Author: T. Dauser
Author: J. Jiang
Author: A.M. Joyce

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