Estimating the size of X-ray lamppost coronae in active galactic nuclei

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F20%3A00538501" target="_blank" >RIV/67985815:_____/20:00538501 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1051/0004-6361/202039158" target="_blank" >https://doi.org/10.1051/0004-6361/202039158</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202039158" target="_blank" >10.1051/0004-6361/202039158</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Estimating the size of X-ray lamppost coronae in active galactic nuclei

Popis výsledku v původním jazyce

We report estimates of the X-ray coronal size of active galactic nuclei in the lamppost geometry. In this commonly adopted scenario, the corona is assumed for simplicity to be a point-like X-ray source located on the axis of the accretion disc. However, the corona must intercept a number of optical/UV seed photons from the disc consistent with the observed X-ray flux, which constrains its size. At least for the sources accreting below the Eddington limit, we find that a Comptonizing lamppost corona can generally exist, but with constraints on its size and height above the event horizon of the black hole depending on the spin. For a maximally spinning black hole, a solution can almost always be found at any height, while for a non-spinning black hole the height must generally be higher than 5 gravitational radii. This is because, for a given luminosity, a higher spin implies more seed photons illuminating the corona, which is due to a larger and hotter inner disc area. The maximal spin solution is favoured, as it predicts an X-ray photon index in better agreement with the observations.

Název v anglickém jazyce

Estimating the size of X-ray lamppost coronae in active galactic nuclei

Popis výsledku anglicky

We report estimates of the X-ray coronal size of active galactic nuclei in the lamppost geometry. In this commonly adopted scenario, the corona is assumed for simplicity to be a point-like X-ray source located on the axis of the accretion disc. However, the corona must intercept a number of optical/UV seed photons from the disc consistent with the observed X-ray flux, which constrains its size. At least for the sources accreting below the Eddington limit, we find that a Comptonizing lamppost corona can generally exist, but with constraints on its size and height above the event horizon of the black hole depending on the spin. For a maximally spinning black hole, a solution can almost always be found at any height, while for a non-spinning black hole the height must generally be higher than 5 gravitational radii. This is because, for a given luminosity, a higher spin implies more seed photons illuminating the corona, which is due to a larger and hotter inner disc area. The maximal spin solution is favoured, as it predicts an X-ray photon index in better agreement with the observations.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

<a href="/cs/project/GA17-02430S" target="_blank" >GA17-02430S: Geometrické vlastnosti korony akrečního disku v aktivních galaktických jádrech</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

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

Název periodika

Astronomy & Astrophysics

ISSN

1432-0746

e-ISSN

—

Svazek periodika

644

Číslo periodika v rámci svazku

December

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

9

Strana od-do

A132

Kód UT WoS článku

000599907300002

EID výsledku v databázi Scopus

2-s2.0-85097865420