2009A&A...504...61I


Query : 2009A&A...504...61I

2009A&A...504...61I - Astronomy and Astrophysics, volume 504, 61-66 (2009/9-2)

X-ray variability time scales in active galactic nuclei.

ISHIBASHI W. and COURVOISIER T.J.-L.

Abstract (from CDS):

X-ray variability in active galactic nuclei (AGN) is commonly analysed in terms of the power spectral density (PSD). The break observed in the power spectrum can be interpreted as a characteristic X-ray variability time scale. Here we study variability properties within the framework of clumpy accretion flows, in which shocks between accreting elements account for the UV and X-ray emissions. We derive a characteristic X-ray time scale, τX, and compare it with the measured PSD break time scale, TB. Good agreement is found in both magnitude and trend. In particular, the model dependence on black hole mass and accretion rate precisely reproduces the empirical relation obtained by McHardy et al. (2006Natur.444..730M). We suggest a possible physical interpretation of the break time scale and briefly discuss the related aspects of optical/UV variability and correlations between different wavelengths.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - radiation mechanisms: general - galaxies: active - ultraviolet: galaxies - X-rays: galaxies

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 Mrk 79 Sy1 07 42 32.8210670808 +49 48 34.783809768   14.74 14.27     ~ 691 1
2 NGC 4051 Sy1 12 03 09.6101337312 +44 31 52.682601288   11.08 12.92 9.94   ~ 2112 1
3 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5637 1
4 Mrk 509 Sy1 20 44 09.7504483224 -10 43 24.727155528   13.35 13.12 10.7   ~ 1223 0
5 NAME MR 2251-178 Sy1 22 54 05.8858611984 -17 34 55.402233708   14.99 14.36 15.12   ~ 413 3

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2023.01.30-03:16:31

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