Počet záznamů: 1
Estimating the size of X-ray lamppost coronae in active galactic nuclei
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SYSNO ASEP 0538501 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Estimating the size of X-ray lamppost coronae in active galactic nuclei Tvůrce(i) Ursini, F. (IT)
Dovčiak, Michal (ASU-R) RID, ORCID
Zhang, Wenda (ASU-R) ORCID
Matt, G. (IT)
Petrucci, P. O. (FR)
Done, C. (GB)Číslo článku A132 Zdroj.dok. Astronomy & Astrophysics. - : EDP Sciences - ISSN 0004-6361
Roč. 644, December (2020)Poč.str. 9 s. Forma vydání Online - E Jazyk dok. eng - angličtina Země vyd. FR - Francie Klíč. slova black hole physics ; active galaxies ; X-rays Vědní obor RIV BN - Astronomie a nebeská mechanika, astrofyzika Obor OECD Astronomy (including astrophysics,space science) CEP GA17-02430S GA ČR - Grantová agentura ČR Způsob publikování Omezený přístup Institucionální podpora ASU-R - RVO:67985815 UT WOS 000599907300002 EID SCOPUS 85097865420 DOI 10.1051/0004-6361/202039158 Anotace 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. Pracoviště Astronomický ústav Kontakt Radka Svašková, bibl@asu.cas.cz, Tel.: 323 620 326 Rok sběru 2021 Elektronická adresa https://doi.org/10.1051/0004-6361/202039158
Počet záznamů: 1