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We develop a new physical model for the broadband spectral energy distribution (SED) of X-ray illuminated accretion discs, that takes into account the mutual interaction of the accretion disc and the X-ray corona, including all relativistic…

High Energy Astrophysical Phenomena · Physics 2022-05-25 M. Dovciak , I. E. Papadakis , E. S. Kammoun , W. Zhang

Radiation emitted from an accretion disk around a massive black hole is a widely discussed model for the UV/soft X-ray excess emission observed in the spectra of many AGN. A self-consistent calculation of the structure and the emerging…

Astrophysics · Physics 2012-07-02 T. Doerrer , H. Riffert , R. Staubert , H. Ruder

Continuum reverberation mapping of AGN can provide new insight into the nature and geometry of the accretion flow. Some of the X-rays from the central corona irradiating the disc are absorbed, increasing the local disc temperature. This…

High Energy Astrophysical Phenomena · Physics 2023-08-21 Scott Hagen , Chris Done

It is established that the ultraviolet (UV) and X-ray emissions in active galactic nuclei (AGN) are tightly correlated. This correlation is observed both in low- and high-redshift sources. In particular, observations of large samples of…

High Energy Astrophysical Phenomena · Physics 2025-03-27 E. Kammoun , I. E. Papadakis , M. Dovčiak , E. Lusso , E. Nardini , G. Risaliti

Genuine spectral energy distributions (SEDs) of the central few parsec of the nearest and brightest active galaxies in the Southern Hemisphere are presented. They are compiled from very high spatial resolution observations in the radio…

In this work, which is a continuation of Castell\'o-Mor et al. (2016), we present new X-ray and infrared (IR) data for a sample of active galactic nuclei (AGN) covering a wide range in Eddington ratio over a small luminosity range. In…

Astrophysics of Galaxies · Physics 2017-02-01 Núria Castelló-Mor , Shai Kaspi , Hagai Netzer , Pu Du , Chen Hu , Luis C. Ho , Jin-Ming Bai , Wei-Hao Bian , Ye-Fei Yuan , Jian-Min Wang

The structure of the accretion flow onto supermassive black holes (SMBH) is not well understood. Standard disc models match to zeroth order in predicting substantial energy dissipation within optically-thick material producing a…

High Energy Astrophysical Phenomena · Physics 2024-10-02 Scott Hagen , Chris Done , John D. Silverman , Junyao Li , Teng Liu , Wenke Ren , Johannes Buchner , Andrea Merloni , Tohru Nagao , Mara Salvato

X-ray variability of active galactic nuclei (AGN) and black hole binaries can be analysed by means of the power spectral density (PSD). The break observed in the power spectrum defines a characteristic variability timescale of the accreting…

High Energy Astrophysical Phenomena · Physics 2015-06-04 W. Ishibashi , T. J. -L. Courvoisier

We calculate the observable signature of a black hole accretion disk with a gap or hole created by a secondary black hole embedded in the disk. We find that for an interesting range of parameters of black hole masses (~10^6 to 10^9 solar…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Kayhan Gultekin , Jon M. Miller

We reexamine the hypothesis that the optical/UV/soft X-ray continuum of Active Galactic Nuclei is thermal emission from an accretion disk. Previous studies have shown that fitting the spectra with the standard, optically thick and…

Astrophysics · Physics 2009-10-28 Ewa Szuszkiewicz , Matthew A. Malkan , Marek A. Abramowicz

In this third paper in a series of three, we present a detailed study of the AGN broadband SED based on a nearby unobscured Type 1 AGN sample. We perform a systematic cross-correlation study of the following key parameters:…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Chichuan Jin , Martin Ward , Chris Done

We calculate spectral energy distributions (SEDs) of steady accretion discs at high accretion rates, as appropriate for bright QSOs, under the assumption that the outer parts are heated sufficiently to maintain marginal gravitational…

Astrophysics · Physics 2009-11-07 Edwin Sirko , Jeremy Goodman

We present ongoing work on the spectral energy distributions (SEDs) of active galactic nuclei (AGNs), derived from X-ray, ultraviolet, optical, infrared and radio photometry and spectroscopy. Our work is motivated by new wide-field imaging…

Astrophysics of Galaxies · Physics 2020-06-17 M. J. I. Brown , K. J. Duncan , H. Landt , M. Kirk , C. Ricci , N. Kamraj

Active Galactic Nuclei (AGN) are believed to be powered by accretion of matter onto a supermassive black hole. A fundamental ingredient in shaping our understanding of AGN is their variability across the entire electromagnetic spectrum.…

High Energy Astrophysical Phenomena · Physics 2025-09-08 Maurizio Paolillo , Iossif Papadakis

A landmark of accretion processes in active galactic nuclei (AGN) is the continuum originating from a complex structure, i.e., an accretion disk and a corona around a supermassive black hole. Modelling the broad-band spectral energy…

Astrophysics of Galaxies · Physics 2023-05-11 Swayamtrupta Panda , Paola Marziani

Stellar black holes (sBHs) are widely believed to exist in the accretion disks of active galactic nuclei (AGNs). Previous studies often focus on the transient emission produced by embedded sBHs. Here, we explore the possible observational…

High Energy Astrophysical Phenomena · Physics 2024-04-12 Shuying Zhou , Mouyuan Sun , Tong Liu , Jian-Min Wang , Jun-Xian Wang , Yongquan Xue

The active galactic nucleus (AGN) phenomena results from a supermassive black hole accreting its surrounding gaseous and dusty material. The infrared (IR) regime provides most of the information to characterize the dusty structures that…

Astrophysics of Galaxies · Physics 2022-05-31 Jianwei Lyu , George Rieke

We use infrared spectroscopy and photometry to empirically define the intrinsic, thermal infrared spectral energy distribution (i.e., 6-100 um SED) of typical active galactic nuclei (i.e., 2-10 keV luminosity, Lx=10^{42}-10^{44} ergs/s…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 J. R. Mullaney , D. M. Alexander , A. D. Goulding , Ryan C. Hickox

The great power offered by photoionization models of Active Galactic Nuclei (AGN) emission-line regions has long been mitigated by the fact that very little is known about the spectral energy distribution (SED) between the Lyman limit,…

High Energy Astrophysical Phenomena · Physics 2020-05-13 Gary Ferland , Chris Done , Chichuan Jin , Hermine Landt , Martin Ward

We propose a solution to the problem of accretion disc sizes in active galactic nuclei being larger when measured by reverberation mapping than predicted by theory. Considering blackbody reprocessing on a disc with thickness profile $H(r)$,…

Astrophysics of Galaxies · Physics 2022-12-28 D. A. Starkey , Jiamu Huang , Keith Horne , Douglas N. C. Lin