2022A&A...666A..11P


Query : 2022A&A...666A..11P

2022A&A...666A..11P - Astronomy and Astrophysics, volume 666A, 11 (2022/10-1)

X-ray illuminated accretion discs and quasar microlensing disc sizes.

PAPADAKIS I.E., DOVCIAK M. and KAMMOUN E.S.

Abstract (from CDS):


Aims. We study the half-light radius versus black hole mass as well as the luminosity versus black hole mass relations in active galactic nuclei (AGN) when the disc is illuminated by the X-ray corona.
Methods. We used KYNSED, a recently developed spectral model for studying broadband spectral energy distribution in AGN. We considered non-illuminated Novikov-Thorne discs and X-ray illuminated discs based on a Novikov-Thorne temperature radial profile. We also considered the case where the temperature profile is modified by a colour-correction factor. In the case of X-ray illumination, we assumed that the X-ray luminosity is equal to the accretion power that is dissipated to the disc below a transition radius and we computed the half-light radius and the disc luminosity for many black hole masses, as well as a wide range of accretion rates, black hole spins, X-ray luminosities and heights of the corona.
Results. The half-light radius of X-ray illuminated radii can be up to ∼3.5 times greater than the radius of a standard disc, even for a non-spinning black hole, based on a wide range of model parameters - as long as the transition radius is larger than three times the radius of the innermost stable circular orbit and the coronal height is greater than ∼40 Rg. This result is due to the fact that the absorbed X-rays act as a secondary source of energy, increasing the disc temperature, and mainly at large radii. Non-illuminated discs are consistent with observations, but only at the 2.5σ level. On the other hand, X-ray illuminated discs can explain both the half-light radius-black hole mass as well as the luminosity-black hole mass relation in AGN, for a wide range of physical parameters. The range of the parameter space is broader in the case where we consider the colour-correction factor. X-ray illuminated discs can explain the data when we observe gravitationally lensed quasars mainly face-on, but also if the mean inclination angle is 60°. In addition, we show that the observed X-ray luminosity of the gravitationally lensed quasars is fully consistent with the X-ray luminosity that is necessary for heating the disc.
Conclusions. X-ray disc illumination was proposed many years ago to explain various features that are commonly observed in the X-ray spectra of AGN. Recently, we showed that X-ray illumination of the accretion disc can also explain the observed UV/optical time-lags in AGN, while in this work, we show that the same model can also account for the quasar micro-lensing disc size problem. These results support the hypothesis of the disc X-ray illumination in AGN.

Abstract Copyright: © I. E. Papadakis et al. 2022

Journal keyword(s): accretion, accretion disks - galaxies: active - quasars: general

VizieR on-line data: <Available at CDS (J/A+A/666/A11): table4.dat table5.dat>

Simbad objects: 16

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Number of rows : 16
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 QSO J0158-4325 QSO 01 58 41.3988 -43 25 03.798   17.2 17.2     ~ 69 1
2 [VV2006] J043814.8-122314 QSO 04 38 14.88 -12 17 14.6     17.15     ~ 222 2
3 QSO B0909+5312 QSO 09 13 01.031 +52 59 28.90   17.29 16.71     ~ 152 1
4 QSO J0924+0219 QSO 09 24 55.8048 +02 19 24.850   18.58 18.36     ~ 138 1
5 [VV98] J095122.6+263513 QSO 09 51 22.5840 +26 35 13.786   17.66 17.31     ~ 114 1
6 8C 0958+561 QSO 10 01 20.6918953728 +55 53 55.593949272   17.16 16.95     ~ 736 3
7 QSO J1004+4112 QSO 10 04 34.9243842216 +41 12 42.771018060   19.14 19.03     ~ 191 1
8 QSO B1104-181 QSO 11 06 33.3845199936 -18 21 23.829049296   15.8 15.9 15.7   ~ 328 1
9 QSO B1115+080A QSO 11 18 16.951 +07 45 58.23   16.61 16.44     ~ 686 2
10 2MASS J11315154-1231588 Sy1 11 31 51.5387 -12 31 58.716           ~ 271 1
11 QSO J1138+0314 QSO 11 38 03.7483141008 +03 14 57.657960780   19.42 19.17     ~ 62 1
12 NGC 5548 Sy1 14 17 59.5400291832 +25 08 12.603122268   14.35 13.73     ~ 2716 0
13 QSO B1520+530 QSO 15 21 44.8 +52 54 49   18.2       ~ 122 2
14 [VV2006] J202610.4-453627 QSO 20 26 10.45 -45 36 27.1           ~ 49 1
15 [VV2006] J203342.1-472343 QSO 20 33 42.12 -47 23 43.9           ~ 124 1
16 QSO J2240+0321 QSO 22 40 30.234 +03 21 30.63           ~ 676 1

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