2012A&A...545A.106S


C.D.S. - SIMBAD4 rel 1.7 - 2021.04.18CEST11:48:35

2012A&A...545A.106S - Astronomy and Astrophysics, volume 545A, 106-106 (2012/9-1)

Origin of the X-ray disc-reflection steep radial emissivity.

SVOBODA J., DOVCIAK M., GOOSMANN R.W., JETHWA P., KARAS V., MINIUTTI G. and GUAINAZZI M.

Abstract (from CDS):

X-ray reflection off the accretion disc surrounding a black hole, together with the associated broad iron Kα line, has been widely used to constrain the innermost accretion-flow geometry and black hole spin. Some recent measurements have revealed steep reflection emissivity profiles in a number of active galactic nuclei and X-ray binaries. We explore the physically motivated conditions that give rise to the observed steep disc-reflection emissivity profiles. We perform a set of simulations based on the configuration of a possible future high-resolution X-ray mission. Computations are carried out for typical X-ray bright Seyfert-1 galaxies. We find that steep emissivity profiles with q∼4-5 (where the emissivity is ε(r)∝r–q) are produced considering either i) a lamp-post scenario where a primary compact X-ray source is located close to the black hole, or ii) the radial dependence of the disc ionisation state. If both effects are taken into account, emissivity profiles as steep as q ∼7 can be obtained from X-ray spectra modelled via conventional reflection models. We also highlight the role of the reflection angular emissivity: the radial emissivity index q is overestimated when the standard limb-darkening law is used to describe the data. Very steep emissivity profiles with q≥7 are naturally obtained by applying reflection models that take into account the radial profile ξ(r) of the disc ionisation induced by a compact X-ray source located close to the central black hole.

Abstract Copyright:

Journal keyword(s): black hole physics - accretion, accretion disks - relativistic processes - galaxies: nuclei

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 4U 0708-49 Sy1 07 08 41.4887418009 -49 33 06.308287663   16.02 15.7 12.7   ~ 441 0
2 2MASX J13251937-3824524 Sy1 13 25 19.3805503234 -38 24 52.611897329   16.64 13.80 15.33   ~ 360 0
3 ESO 383-35 Sy1 13 35 53.7686909139 -34 17 44.139127597   13.89 13.61 8.9   ~ 1400 0
4 [GHJ2008] 3 HXB 16 50 00.980 -49 57 43.60     11.89     K4V 358 0
5 V* V821 Ara HXB 17 02 49.3810714542 -48 47 23.163091737 16.20 16.30 15.5     ~ 1826 0
6 HD 226868 HXB 19 58 21.6758193269 +35 12 05.782512305 9.38 9.72 8.91 8.42   O9.7Iabpvar 3997 0

    Equat.    Gal    SGal    Ecl

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2021.04.18-11:48:35

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