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Related papers: A Survey Length for AGN Variability Studies

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Previous works concerning active galactic nuclei (AGN) variability (e.g., Blandford \& McKee 1982) have assumed that the emission characteristics of illuminated clouds are purely a function of the instant continuum flux to which they are…

Astrophysics · Physics 2009-10-28 Jason A. Taylor

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 classic classification scheme for Active Galactic Nuclei (AGNs) was recently challenged by the discovery of the so-called changing-state (changing-look) AGNs (CSAGNs). The physical mechanism behind this phenomenon is still a matter of…

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

Intensive broadband reverberation mapping campaigns have shown that AGN variability is significantly more complex than expected from disc reverberation of the variable X-ray illumination. The UV/optical variability is highly correlated and…

High Energy Astrophysical Phenomena · Physics 2024-05-02 Scott Hagen , Chris Done , Rick Edelson

The characteristic timescale at which the variability of active galactic nuclei (AGNs) turns from red noise to white noise can probe the accretion physics around supermassive black holes (SMBHs). A number of works have studied the…

Astrophysics of Galaxies · Physics 2024-09-17 Guowei Ren , Shuying Zhou , Mouyuan Sun , Yongquan Xue

Continuum reverberation mapping (RM) is a powerful technique for constraining the accretion disk structure in active galactic nuclei (AGNs). In typical cases, the shorter-wavelength emission is used as the reference, and a positive time lag…

Astrophysics of Galaxies · Physics 2026-05-05 Chen MuLin , Cheng PeiZhen , Chen XingQian , Gu Ying , Zheng Qi , Liao GuiLin , Zhang XueGuang

LSST is expected to yield ~10^7 light curves over the course of its mission, which will require a concerted effort in automated classification. Stochastic processes provide one means of quantitatively describing variability with the…

Instrumentation and Methods for Astrophysics · Physics 2017-04-26 J. C. Zinn , C. S. Kochanek , S. Kozłowski , A. Udalski , M. K. Szymański , I. Soszyński , Ł. Wyrzykowski , K. Ulaczyk , R. Poleski , P. Pietrukowicz , J. Skowron , P. Mróz , M. Pawlak

Active galactic nuclei (AGN) light curves observed with different wavebands show that the variability in longer wavelength bands lags the variability in shorter wavelength bands. Measuring these lags, or reverberation mapping, is used to…

High Energy Astrophysical Phenomena · Physics 2023-11-21 Amy Secunda , Yan-Fei Jiang , Jenny E. Greene

We gauge the impact of spacecraft-induced effects on the inferred variability properties of the light curve of the Seyfert 1 AGN Zw 229-15 observed by \Kepler. We compare the light curve of Zw 229-15 obtained from the Kepler MAST database…

Astrophysics of Galaxies · Physics 2015-09-01 Vishal P. Kasliwal , Michael S. Vogeley , Gordon T. Richards , Joshua Williams , Michael T. Carini

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

The upcoming photometric surveys, such as the Rubin Observatory's Legacy Survey of Space and Time (LSST) will monitor unprecedented number of active galactic nuclei (AGN) in a decade long campaign. Motivated by the science goals of LSST,…

Changing-look active galactic nuclei (CL AGNs) show large changes in luminosity and optical spectral state on time-scales of a few years, and provide a valuable probe of time-dependent accretion in the disc-BLR-torus system. We present a…

Astrophysics of Galaxies · Physics 2026-03-19 Yu Tao , Jie Tang , Xuan Wei

Active galactic nucleus (AGN) emission is dominated by stochastic, aperiodic variability which overwhelms any periodic/quasi-periodic signal (QPO) if one is present. The Auto Correlation Function (ACF) and Phase Dispersion Minimization…

High Energy Astrophysical Phenomena · Physics 2021-10-28 S. Krishnan , A. G. Markowitz , A. Schwarzenberg-Czerny , M. J. Middleton

To gain insights into long-term Active Galactic Nuclei (AGN) variability, we analyze an AGN sample from the Sloan Digital Sky Survey (SDSS) and compare their photometry with observations from the Hyper Suprime-Cam survey (HSC) observed…

Astrophysics of Galaxies · Physics 2020-02-12 Neven Caplar , Theodore Pena , Sean D. Johnson , Jenny E. Greene

Accreting supermassive black holes at the centres of galaxies are the engine of active galactic nuclei (AGN). X-ray light curves of unabsorbed AGN show dramatic random variability on timescales ranging from seconds to years. The power…

High Energy Astrophysical Phenomena · Physics 2025-10-29 Mehdy Lefkir , Simon Vaughan , Mike Goad , Daniela Huppenkothen , Phil Uttley

One of the most important features in active galactic nuclei (AGN) is the variability of their emission. Variability has been discovered at X-ray, UV, and radio frequencies on time scales from hours to years. Among the AGN family and…

High Energy Astrophysical Phenomena · Physics 2015-06-15 L. Hernández-García , O. González-Martín , I. Márquez , J. Masegosa

Gamma-ray bursts (GRB) are extremely energetic events and produce highly diverse light curves. Light curves are believed to be resulting from internal shocks reflecting the activities of the GRB central engine. Hence their temporal studies…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Narayana P. Bhat

It has been alleged in several papers that the so called delayed continuous-time random walks (DCTRWs) provide a model for the one-dimensional telegraph equation at microscopic level. This conclusion, being widespread now, is strange, since…

Statistical Mechanics · Physics 2012-03-01 Sergey A. Rukolaine , Alexander M. Samsonov

Single particle tracking allows probing how biomolecules interact physically with their natural environments. A fundamental challenge when analysing recorded single particle trajectories is the inverse problem of inferring the physical…

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