Περίληψη |
The main objective of this work was to study the impact of X-ray variability on the radial
temperature profile of the accretion disks in AGN.
We began by studying the disk temperature profile in the case of a steady, Keplerian,
geometrically thin and optically thick accretion disk as a function of radius. This included
examining how the black hole mass and accretion rate affect the disk temperature. We then
considered the temperature radial profile of accretion disks assuming the relativistic gravitational potential to obtain a more accurate radial temperature profile, and we explored how BH
spin influences the disk temperature.
Next, we assumed a model of an X-ray illuminated disk with a “lamp-post” corona geometry.
Two corona powering mechanisms were considered: one where all the accretion power below
a transfer radius is transferred to the corona, and another where the corona is powered by an
external source. We studied the radial temperature profile of the illuminated disk, for various
values of corona luminosities and heights, and explored how these parameters influence the disk
temperature at various radii.
We then studied the time evolution of the disk’s radial temperature profile in the case
when X-rays that illuminate the disk are variable. First, we considered a single flash of X-ray radiation, and we studied the time delays between the emission of X-rays and the disk’s
response to the radiation for various corona heights. Finally, using the results of Kammoun
et al. (2024), we examined how the X-ray variability, driven by variations in corona height and
luminosity, affects the evolution of the disk temperature in NGC 5548.
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