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Properties of AGN coronae in the NuSTAR era – II. Hybrid plasma

Fabian, A. C. and Lohfink, A. M. and Belmont, R. and Malzac, J. and Coppi, P. (2017) Properties of AGN coronae in the NuSTAR era – II. Hybrid plasma. Monthly Notices of the Royal Astronomical Society, 467 (3). pp. 2566-2570. ISSN 0035-8711. doi:10.1093/mnras/stx221.

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The corona, a hot cloud of electrons close to the centre of the accretion disc, produces the hard X-ray power-law continuum commonly seen in luminous active galactic nuclei. The continuum has a high-energy turnover, typically in the range of one to several 100 keV and is suggestive of Comptonization by thermal electrons. We are studying hard X-ray spectra of AGN obtained with NuSTAR after correction for X-ray reflection and under the assumption that coronae are compact, being only a few gravitational radii in size as indicated by reflection and reverberation modelling. Compact coronae raise the possibility that the temperature is limited and indeed controlled by electron–positron pair production, as explored earlier (Paper I). Here, we examine hybrid plasmas in which a mixture of thermal and non-thermal particles is present. Pair production from the non-thermal component reduces the temperature leading to a wider temperature range more consistent with observations.

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URLURL TypeDescription Paper
Fabian, A. C.0000-0002-9378-4072
Additional Information:© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 January 23. Received 2017 January 13; in original form 2016 December 14. Published: 09 February 2017. We thank the referee for helpful comments. ACF and AL acknowledge support from ERC Advanced Grant FEEDBACK 340442. R. Belmont and J. Malzac acknowledge financial support from the French National Research Agency (CHAOS project ANR-12-BS05-0009).
Subject Keywords:black hole physics –X-rays: binaries
Issue or Number:3
Record Number:CaltechAUTHORS:20170127-082425783
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Official Citation:A. C. Fabian, A. Lohfink, R. Belmont, J. Malzac, P. Coppi; Properties of AGN coronae in the NuSTAR era – II. Hybrid plasma, Monthly Notices of the Royal Astronomical Society, Volume 467, Issue 3, 1 June 2017, Pages 2566–2570,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73770
Deposited By: Joy Painter
Deposited On:27 Jan 2017 19:07
Last Modified:11 Nov 2021 05:21

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