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Related papers: Characterizing the $\gamma$-Ray Variability of Act…

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The UV/optical light curves of Active Galactic Nuclei (AGNs) are commonly described by the Damped Random Walk (DRW) model. However, the physical interpretation of the damping timescale, a key parameter in the DRW model, remains unclear.…

High Energy Astrophysical Phenomena · Physics 2024-03-05 Shuying Zhou , Mouyuan Sun , Zhen-Yi Cai , Guowei Ren , Jun-Xian Wang , Yongquan Xue

Discrepancies between reported structure function (SF) slopes and their overall flatness as compared to expectations from the damped random walk (DRW) model, which generally well describes the variability of active galactic nuclei (AGNs),…

Astrophysics of Galaxies · Physics 2017-03-06 Szymon Kozłowski

We present results of recurrence analysis of 46 active galactic nuclei (AGN) using light curves from the 157-month catalog of the Swift Burst Alert Telescope (BAT) in the 14-150 keV band. We generate recurrence plots and compute recurrence…

High Energy Astrophysical Phenomena · Physics 2022-11-28 R. A. Phillipson , M. S. Vogeley , P. T. Boyd

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

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

Machine learning is a promising tool to reconstruct time-series phenomena, such as variability of active galactic nuclei (AGN), from sparsely-sampled data. Here we use three Continuous Auto-Regressive Moving Average (CARMA) representations…

High Energy Astrophysical Phenomena · Physics 2022-04-21 Xinyue Sheng , Nicholas Ross , Matt Nicholl

In this manuscript, we study properties of long-term optical variability of a large sample of 106 SDSS spectroscopically confirmed AGN with double-peaked broad low-ionization emission lines (double-peaked emitters). The long-term optical…

Astrophysics of Galaxies · Physics 2016-10-12 XueGuang Zhang , LongLong Feng

We use nine years of gamma-ray data provided by the Fermi Large Area Telescope (LAT) to systematically study the light curves of more than two thousand active galactic nuclei (AGN) included in recent Fermi-LAT catalogs. Ten different…

High Energy Astrophysical Phenomena · Physics 2020-07-01 P. Peñil , A. Domínguez , S. Buson , M. Ajello , J. Otero-Santos , J. A. Barrio , R. Nemmen , S. Cutini , B. Rani , A. Franckowiak , E. Cavazzuti

The 4 Ms Chandra Deep Field-South (CDF-S) and other deep X-ray surveys have been highly effective at selecting active galactic nuclei (AGN). However, cosmologically distant low-luminosity AGN (LLAGN) have remained a challenge to identify…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 M. Young , W. N. Brandt , Y. Q. Xue , M. Paolillo , D. M. Alexander , F. E. Bauer , B. D. Lehmer , B. Luo , O. Shemmer , D. P. Schneider , C. Vignali

We test the consistency of active galactic nuclei (AGN) optical flux variability with the $\textit{damped random walk}$ (DRW) model. Our sample consists of 20 multi-quarter $\textit{Kepler}$ AGN light curves including both Type 1 and 2…

Astrophysics of Galaxies · Physics 2015-07-03 Vishal P. Kasliwal , Michael S. Vogeley , Gordon T. Richards

Individual light curves of active galactic nuclei (AGNs) are nowadays successfully modelled with the damped random walk (DRW) stochastic process, characterized by the power exponential covariance matrix of the signal, with the power…

Astrophysics of Galaxies · Physics 2016-05-04 Szymon Kozlowski

We systematically analyze X-ray variability of active galactic nuclei (AGNs) in the 7~Ms \textit{Chandra} Deep Field-South survey. On the longest timescale ($\approx~17$ years), we find only weak (if any) dependence of X-ray variability…

Analysing the long-term radio variability of active galactic nuclei (AGNs) is essential to understanding the physics of relativistic jets launched by supermassive black holes. We aim to connect the characteristic timescales obtained from a…

Astrophysics of Galaxies · Physics 2026-05-07 Sofia Kankkunen , Merja Tornikoski , Talvikki Hovatta

The characteristic timescale ($\tau$) of continuum variability of the accretion disk in active galactic nuclei (AGNs) is known to be related to the thermal timescale, which is predicted to scale with AGN luminosity ($L$) and restframe…

Astrophysics of Galaxies · Physics 2025-03-26 Suyeon Son , Minjin Kim , Luis C. Ho

Both long and short gamma-ray bursts (GRBs) are expected to occur in the dense environments of active galactic nuclei (AGN) accretion disks. As these bursts propagate through the disks they live in, they photoionize the medium causing…

High Energy Astrophysical Phenomena · Physics 2023-03-29 Michael Ray , Davide Lazzati , Rosalba Perna

An increasing number of Active Galactic Nuclei (AGNs) exhibit broad, double-peaked Balmer emission lines,which represent some of the best evidence for the existence of relatively large-scale accretion disks in AGNs. A set of 20…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Karen T. Lewis , Michael Eracleous , Thaisa Storchi-Bergmann

We present our statistical analysis of the connection between active galactic nuclei (AGN) variability and physical properties of the central supermassive black hole (SMBH). We constructed optical light curves using data from the QUEST-La…

Astrophysics of Galaxies · Physics 2018-09-19 P. Sánchez-Sáez , P. Lira , J. Mejía-Restrepo , L. C. Ho , P. Arévalo , M. Kim , R. Cartier , P. Coppi

AGN, powered by accretion onto SMBHs, are thought to be scaled up versions of Galactic black hole X-ray binaries (BH-XRBs). In the past few years evidence of such correspondence include similarities in the broadband shape of the X-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-05 O. Gonzalez-Martin , S. Vaughan

Context. A defining characteristic of active galactic nuclei (AGN) that distinguishes them from other astronomical sources is their stochastic variability, which is observable across the entire electromagnetic spectrum. Upcoming optical…

Context: Variations in the mass accretion rate appear to be responsible for the rapid transitions in spectral type that are observed in increasingly more active galactic nuclei (AGNs). These objects are now labeled "changing-look" AGNs and…

Astrophysics of Galaxies · Physics 2020-04-15 F. Marin , D. Hutsemékers