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Related papers: Ultrafast Variability in AGN Jets: Intermittency a…

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We perform simulations to study the effects of active galactic nuclei (AGNs) radiation and wind feedback on the properties of slowly rotating accretion flow at parsec scale. We find that when only radiative feedback is considered, outflows…

High Energy Astrophysical Phenomena · Physics 2019-09-11 De-Fu Bu , Xiao-Hong Yang

We present the expected variability features in the context of the Synchro- Self-Compton (SSC) model of emission from Active Galactic Nuclei (AGNs) and show that the homogeneous SSC model describes well the observed multi- wavelength…

Astrophysics · Physics 2007-05-23 A. Mastichiadis , J. G. Kirk

Accretion rates onto AGN are likely to be extremely variable on short timescales; much shorter than the typical cooling time of X-ray emitting gas in elliptical galaxies and galaxy clusters. Using the Langevin approach it is shown that, for…

Astrophysics · Physics 2009-11-13 Edward C. D. Pope

We examine the continuum variability of active galactic nuclei (AGNs) by analyzing the multi-epoch spectroscopic data from the Sloan Digital Sky Survey. To achieve this, we utilized approximately 2 million spectroscopy pairwise combinations…

Astrophysics of Galaxies · Physics 2025-11-13 Minjin Kim , Suyeon Son , Luis C. Ho

We present two- and three-dimensional hydrodynamic simulations of $\sim$kpc-scale AGN jets with mean jet powers in the range $1-7\times10^{45}\,$erg~s$^{-1}$, in which the jet power varies (through variation of the Lorentz factor) according…

High Energy Astrophysical Phenomena · Physics 2023-06-01 Henry W. Whitehead , James H. Matthews

Active galactic nuclei (AGNs) exhibit variability in their luminosities with timescales that correlate with the mass of the black hole at the centre of the AGN. Presently, the empirical correlation lacks sufficient precision to confidently…

Astrophysics of Galaxies · Physics 2025-12-22 Adrien Hélias , Sarah C. Gallagher , Pauline Barmby

Partial dust obscuration in active galactic nuclei (AGN) has been proposed as a potential explanation for some cases of AGN variability. The dust-gas mixture present in AGN tori is accelerated by radiation pressure, leading to the launching…

Astrophysics of Galaxies · Physics 2024-10-08 Nadine H. Soliman , Philip F. Hopkins

We present the first systematic study of short-timescale X-ray variability in radio-quiet active galactic nuclei (AGN), utilizing archival Chandra observations of approximately 3,000 broad-line AGN selected from the SDSS and DESI…

High Energy Astrophysical Phenomena · Physics 2025-12-09 Xiurui Zhao , Luca Comisso , Stefano Marchesi , Marco Ajello , Elias Kammoun , Yue Shen , Qiaoya Wu

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

Adopting the hypothesis that the nonthermal emission of Active Galactic Nuclei (AGN) is primarily due to the acceleration of protons, we construct a simple model in which the interplay of acceleration and losses can be studied together with…

Astrophysics · Physics 2008-02-03 A. Mastichiadis J. G. Kirk

Under the unified model for active galactic nuclei (AGNs), narrow-line (Type 2) AGNs are, in fact, broad-line (Type 1) AGNs but each with a heavily obscured accretion disk. We would therefore expect the optical continuum emission from Type…

A fraction of active galactic nuclei (AGN) exhibit dramatic variability, which is observed on timescales down to minutes in the X-ray band. We introduce the case study of 1H 1934-063 (z = 0.0102), a Narrow-line Seyfert 1 (NLS1) among the…

High Energy Astrophysical Phenomena · Physics 2018-11-07 Sara E. Frederick , Erin Kara , Christopher S. Reynolds , Ciro Pinto , Andrew C. Fabian

The long-term variability study over a range of black hole (BH) mass systems from the microquasars of stellar-mass black holes to the Active Galactic Nuclei (AGNs) of supermassive black holes, in $\gamma$-rays offers new insights into the…

High Energy Astrophysical Phenomena · Physics 2024-10-10 Ajay Sharma , Raj Prince , Debanjan Bose

Emission-line variability studies have the potential to provide key information about the structures of the near-nuclear outflow regions of AGN. Here we present a VLT/Xshooter spectrum of the nucleus of the ULIRG F01004-2237 that was taken…

Astrophysics of Galaxies · Physics 2021-04-28 C. Tadhunter , M. Patel , J. Mullaney

We study outflows driven by Active Galactic Nuclei (AGNs) using high- resolution simulations of idealized z=2 isolated disk galaxies. Episodic accretion events lead to outflows with velocities >1000 km/s and mass outflow rates up to the…

Astrophysics of Galaxies · Physics 2015-06-18 Jared M. Gabor , Frédéric Bournaud

We study the effect of non-relativistic, thermal matter in the jets of active galaxies (AGN) on the low-frequency non-thermal emission and the variability thereof. In matter-dominated jets, sizable quantities of gas should exist, in…

Astrophysics · Physics 2009-11-10 M. Siewert , M. Pohl , R. Schlickeiser

Active galactic nuclei (AGN) with jets seen at small viewing angles are the most luminous and abundant objects in the $\gamma$-ray sky. AGN with jets misaligned along the line-of-sight appear fainter in the sky, but are more numerous than…

High Energy Astrophysical Phenomena · Physics 2015-06-15 M. Di Mauro , F. Calore , F. Donato , M. Ajello , L. Latronico

The apparent position of jet base (core) in radio-loud active galactic nuclei changes with frequency because of synchrotron self-absorption. Studying this `core shift` effect enables us to reconstruct properties of the jet regions close to…

Astrophysics of Galaxies · Physics 2019-03-07 A. V. Plavin , Y. Y. Kovalev , A. B. Pushkarev , A. P. Lobanov

We model the broadband (optical/UV and X-ray) continuum spectrum of the "changing-look" active galactic nucleus (AGN) Mrk 1018 as it fades from Seyfert 1 to 1.9 in $\sim 8$ years. The brightest spectrum, with Eddington ratio $L/L_{\rm…

Astrophysics of Galaxies · Physics 2018-08-08 Hirofumi Noda , Chris Done

The group velocity of light in material around the AGN jet is acquiescently one (c as a unit), but this is only a hypothesis. Here, we re-derive apparent superluminal and Doppler formulas for the general case (it is assumed that the group…

High Energy Astrophysical Phenomena · Physics 2015-02-25 Wen-Po Liu , Li-Yan Liu , Chun-Cheng Wang
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