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Identifier |
000457414 |
Title |
Theoretical model fits to the optical/UV spectral energy distributions of AGN |
Alternative Title |
Προσαρμογή θεωρητικών μοντέλων στο οπτικό/υπεριώδες φάσμα ενεργών γαλαξιακών πυρήνων |
Author
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Παπουτσής, Μάριος Χ.
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Thesis advisor
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Παπαδάκης, Ιωσήφ
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Reviewer
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Παυλίδου, Βασιλική
Κυλάφης, Νικόλαος
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Abstract |
In this work, we aim to study simple theoretical models of the accretion disk in AGN,
compute the resulting model SED, and then compare it with observed SEDs. We consider the Novikov-Thorne (1973)
model and we take into account the effects of electron opacity, i.e. Thomson scattering and free-free
absorption, as well as Compton scattering. Regarding the first two processes, we consider the case
of a modified blackbody spectrum, while regarding the latter process we consider the case of a
colour correction to the blackbody emission formula. We then create model accretion disk spectra
for a wide range of AGN parameters (i.e. black hole mass, accretion rate, spin, and inclination)
and fit their average to the observed mean SED of 119,652 SDSS quasars (taken from Krawczyk et
al. 2013). In this way, we can investigate whether the current accretion disk models are consistent
with the observed AGN SED, and at the same time determine the bet-fit black hole mass, accretion
rate, spin, and inclination distribution for a large sample of AGN. The sample size is one of the
main differences between our modeling and previous works. In addition, we use a rather innovative
way of accounting for the electron opacity effects and also include the relativistic effects of photon
propagation from the disk to the observer at infinity as computed by Dovciak (2004). We conclude that the accretion
disk models we consider cannot fit the observed quasar SEDs well. Therefore, models that include the intrinsic reddening of AGN
or the illumination of the disk from the AGN X-ray source might be required.
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Language |
English |
Subject |
Accretion disks |
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Galaxies: active |
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Δίσκοι προσαύξησης |
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Ενεργοί γαλαξίες |
Issue date |
2023-07-28 |
Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/6/0/b/metadata-dlib-1687847903-834452-30126.tkl
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Views |
483 |