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Related papers: A model for AGN variability on multiple timescales

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Many Active Galactic Nuclei (AGN) are surrounded by gas which absorbs the radiation produced by accretion onto the central black hole and obscures the nucleus from direct view. The dust component of the gas greatly enhances the effect of…

Astrophysics · Physics 2009-11-13 A. C. Fabian , R. V. Vasudevan , P. Gandhi

Understanding the physics and geometry of accretion and ejection around super massive black holes (SMBHs) is important to understand the evolution of active galactic nuclei (AGN) and therefore of the large scale structures of the Universe.…

Astrophysics of Galaxies · Physics 2019-11-11 Margherita Giustini , Daniel Proga

I will review the tips learned from panchromatic modeling of active galactic nuclei (AGNs), based on our recent work to study the relationship between AGN and star formation (SF). Several AGN SED models are compared, and signifficant AGN…

Astrophysics of Galaxies · Physics 2020-06-17 Y. Sophia Dai

The James Webb Space Telescope (JWST) observations enable the exploration of active galactic nuclei (AGNs) with broad-line emission in the early universe. Despite their clear radiative and morphological signatures of AGNs in rest-frame…

High Energy Astrophysical Phenomena · Physics 2025-05-15 Kohei Inayoshi , Shigeo S. Kimura , Hirofumi Noda

We present our sixth work in a series dedicated to variability studies of active galactic nuclei (AGN) based on the survey of the COSMOS field by the VLT Survey Telescope (VST). Its 54 r-band visits over 3.3 yr and single-visit depth of…

Astrophysics of Galaxies · Physics 2022-08-24 D. De Cicco , F. E. Bauer , M. Paolillo , P. Sánchez-Sáez , W. N. Brandt , F. Vagnetti , G. Pignata , M. Radovich , M. Vaccari

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

The general picture of how thermal AGNs work has become clearer in recent years but major observational puzzles threaten to undermine this picture. These puzzles include AGNs with extremely asymmetric emission line profiles, inconsistent…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-14 C. Martin Gaskell

Black hole accretion flows show rapid X-ray variability. The Power Spectral Density (PSD) of this is typically fit by a phenomenological model of multiple Lorentzians for both the broad band noise and Quasi-Periodic Oscillations (QPOs). Our…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Adam Ingram , Chris Done

Large extragalactic surveys allow us to trace, in a statistical sense, how supermassive black holes, their host galaxies, and their dark matter halos evolve together over cosmic time, and so explore the consequences of AGN feedback on…

Astrophysics of Galaxies · Physics 2015-05-14 Ryan C. Hickox

We use deep Chandra X-ray imaging to measure the distribution of specific black hole accretion rates ($L_X$ relative to the stellar mass of the galaxy) and thus trace AGN activity within star-forming and quiescent galaxies, as a function of…

High Energy Astrophysical Phenomena · Physics 2017-12-27 James Aird , Alison L. Coil , Antonis Georgakakis

A common feature of Active Galactic Nuclei (AGN) is their random variations in brightness across the whole emission spectrum, from radio to $\gamma$-rays. Studying the nature and origin of these fluctuations is critical to characterising…

Astrophysics of Galaxies · Physics 2025-10-17 Mehdy Lefkir , Simon Vaughan , Daniela Huppenkothen , Phil Uttley , Vysakh Anilkumar

The local X-ray AGN population appears to follow a growth cycle regulated by the AGN's own radiation, marked by changes in their obscuration and Eddington ratio during accretion events. Because AGN in infrared-selected galaxies are more…

This paper presents the results of a study of X-ray spectral and flux variability on time scales from months to years, of the 123 brightest objects (including 46 type-1 AGN and 28 type-2 AGN) detected with XMM-Newton in the Lockman Hole…

Astrophysics · Physics 2009-11-13 S. Mateos , X. Barcons , F. J. Carrera , M. J. Page , M. T. Ceballos , G. Hasinger , A. C. Fabian

Modeling the spectral energy distribution (SED) of active galactic nuclei (AGN) plays a very important role in constraining modern cosmological simulations of galaxy formation. Here, we utilize an advanced supermassive black hole (SMBH)…

Astrophysics of Galaxies · Physics 2026-03-23 Tong Su , Qi Guo , Erlin Qiao , Wenxiang Pei , Luis C. Ho , Cedric G. Lacey

Black holes depend only on mass and spin, while what we see from the accretion flow in steady state depends also on mass accretion rate and (weakly) inclination. Hence we should be able to scale the accretion flow properties from the…

High Energy Astrophysical Phenomena · Physics 2014-05-13 Chris Done

We conduct an analysis of over 60,000 dwarf galaxies (7<=log(M_*/M_\odot)<=10) in search of photometric variability indicative of active galactic nuclei (AGNs). Using data from the Young Supernova Experiment (YSE), a time domain survey on…

Galactic outflows are now commonly observed in starburst and active galactic nuclei (AGN) host galaxies. Yet, there is no clear consensus on their physical driving mechanism(s). We have previously shown that AGN radiative feedback, driven…

Astrophysics of Galaxies · Physics 2018-10-17 W. Ishibashi , A. C. Fabian

In this paper, standard accretion disk models of AGNs are tested using light curves of 26 objects well observed for reverberation mapping. Time scales of variations are estimated by the most common definition of the variability time scale…

Astrophysics · Physics 2014-01-10 H. T. Liu , J. M. Bai , X. H. Zhao , L. Ma

We investigate a large number of cosmological evolution models for QSOs and Active Galactic Nuclei (AGN). We introduce a spectrum-luminosity correlation as a new input parameter and adopt the estimated mass function (MF) of massive black…

Astrophysics · Physics 2009-10-31 Yun-Young Choi , Jongmann Yang , Insu Yi

Axion-like particles (ALPs) are compelling candidates for dark matter and potential portals to new physics beyond the Standard Model. Photons traversing magnetized regions can convert into ALPs, producing characteristic, energy-dependent…

High Energy Astrophysical Phenomena · Physics 2026-01-23 Denys Malyshev , Lidiia Zadorozhna , Yuriy Bidasyuk , Andrea Santangelo , Oleg Ruchayskiy
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