X-ray reverberation modelling of the observed UV/optical power spectra of quasars

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00639689" target="_blank" >RIV/67985815:_____/25:00639689 - isvavai.cz</a>

Výsledek na webu

<a href="https://hdl.handle.net/11104/0370245" target="_blank" >https://hdl.handle.net/11104/0370245</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202554220" target="_blank" >10.1051/0004-6361/202554220</a>

Jazyk výsledku

angličtina

Název v původním jazyce

X-ray reverberation modelling of the observed UV/optical power spectra of quasars

Popis výsledku v původním jazyce

Context. Over the past decade, a significant amount of effort has been put into investigating the ultraviolet (UV) and optical variability of active galactic nuclei (AGNs). Comprehensive studies of intensive multi-wavelength monitoring and surveys of local and high-redshift AGNs have shown that X-ray illumination of AGN accretion discs is a potential explanation for the observed variability. Aims. Our main objective is to study the UV/optical power spectra of AGNs under the assumption of X-ray reverberation and to test whether this model can explain the observed power spectra of distant quasars. Methods. We computed the disc transfer function in the case of X-ray reverberation using a recent physical model and studied its dependence on the parameters of the model. This model allows us to explore the variability of X-ray illuminated discs under the scenario in which the X-ray corona is powered by the accretion process or by an external source. We then calculated UV/optical power spectra using the disc transfer function and assuming a bending power law for the X-ray power spectrum. We fitted our models to the observed power spectra of quasars determined by a recent power spectrum analysis of the SDSS Stripe-82 light curves. Results. We demonstrate that X-ray reverberation can fit the power spectra of quasars in our sample well at all wavelengths, from similar to 1300 Å up to 4000 Å. Our best-fit models imply that the X-ray corona is powered by the accretion disc, and that the black hole spin is probably lower than 0.7, while the X-ray corona height is in the range of 20 60 R-g. This is in agreement with previous findings from the application of the X-ray reverberation model to the quasar micro-lensing disc size problem, as well as recent time-lag measurements.

Název v anglickém jazyce

X-ray reverberation modelling of the observed UV/optical power spectra of quasars

Popis výsledku anglicky

Context. Over the past decade, a significant amount of effort has been put into investigating the ultraviolet (UV) and optical variability of active galactic nuclei (AGNs). Comprehensive studies of intensive multi-wavelength monitoring and surveys of local and high-redshift AGNs have shown that X-ray illumination of AGN accretion discs is a potential explanation for the observed variability. Aims. Our main objective is to study the UV/optical power spectra of AGNs under the assumption of X-ray reverberation and to test whether this model can explain the observed power spectra of distant quasars. Methods. We computed the disc transfer function in the case of X-ray reverberation using a recent physical model and studied its dependence on the parameters of the model. This model allows us to explore the variability of X-ray illuminated discs under the scenario in which the X-ray corona is powered by the accretion process or by an external source. We then calculated UV/optical power spectra using the disc transfer function and assuming a bending power law for the X-ray power spectrum. We fitted our models to the observed power spectra of quasars determined by a recent power spectrum analysis of the SDSS Stripe-82 light curves. Results. We demonstrate that X-ray reverberation can fit the power spectra of quasars in our sample well at all wavelengths, from similar to 1300 Å up to 4000 Å. Our best-fit models imply that the X-ray corona is powered by the accretion disc, and that the black hole spin is probably lower than 0.7, while the X-ray corona height is in the range of 20 60 R-g. This is in agreement with previous findings from the application of the X-ray reverberation model to the quasar micro-lensing disc size problem, as well as recent time-lag measurements.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

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

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

701

Číslo periodika v rámci svazku

Sept.

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

13

Strana od-do

A295

Kód UT WoS článku

001579007600009

EID výsledku v databázi Scopus

2-s2.0-105017370060