Explaining the UV to X-ray correlation in active galactic nuclei within the framework of X-ray illumination of accretion discs

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00619763" target="_blank" >RIV/67985815:_____/25:00619763 - isvavai.cz</a>

Result on the web

<a href="https://hdl.handle.net/11104/0366404" target="_blank" >https://hdl.handle.net/11104/0366404</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202452629" target="_blank" >10.1051/0004-6361/202452629</a>

Result language

angličtina

Original language name

Explaining the UV to X-ray correlation in active galactic nuclei within the framework of X-ray illumination of accretion discs

Original language description

Context. It is established that the ultraviolet (UV) and X-ray emission in active galactic nuclei (AGN) is tightly correlated. This correlation is observed both in low- and high-redshift sources. In particular, observations of large samples of quasars revealed a non-linear correlation between UV and X-rays. The physical origin of this correlation is poorly understood. Aims. We explore this observed correlation in the framework of the X-ray illumination of the accretion disc by a central source. We showed previously that this model successfully explains the continuum UV/optical time delays, variability, and the broadband spectral energy distribution in AGN. Methods. We used this model to produce 150 000 model spectral energy distributions, assuming a uniform distribution of the model parameters. We computed the corresponding UV (2500 angstrom) and X-ray (2 keV) monochromatic luminosities and selected only the model data points that agreed with the observed UV-to-X-ray correlation. Results. Our results show that the X-ray illuminated accretion disc model can reproduce the observed correlation for a subset of model configurations with a non-uniform distribution of the black hole mass (M-BH), accretion rate ((m) over dot/(m) over dot(Edd)), and power transferred from the accretion disc to the corona (L-transf/L-disc). In addition, our results reveal a correlation between M-BH and (m) over dot/(m) over dot(Edd) and between (m) over dot/(m) over dot(Edd) and L-transf/L-disc that explains the observed X-ray-UV correlation. We also present evidence based on observed luminosities that supports our findings. We finally discuss the implications of our results.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

697

Issue of the periodical within the volume

May

Country of publishing house

FR - FRANCE

Number of pages

11

Pages from-to

A55

UT code for WoS article

001482897500009

EID of the result in the Scopus database

2-s2.0-105005004890