Details

Autor(en) / Beteiligte

• Fabian, A. C.
• Lohfink, A.
• Belmont, R.
• Malzac, J.
• Coppi, P.

Titel

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

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2017-06, Vol.467 (3), p.2566-2570

Ort / Verlag

Oxford University Press

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Abstract 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.