English
Related papers

Related papers: Revisiting Stochastic Variability of AGNs with Str…

200 papers

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

A simple, model-independent method to quantify the stochastic variability of active galactic nuclei (AGNs) is the structure function (SF) analysis. If the SF for the timescales shorter than the decorrelation timescale $\tau$ is a single…

Astrophysics of Galaxies · Physics 2017-02-08 Szymon Kozłowski

The origin of the optical flux variability in active galactic nuclei (AGN) is largely unknown. Previous studies have correlated features of the variability structure function (SF) with AGN properties, though they mostly involved…

Astrophysics of Galaxies · Physics 2026-05-06 Ashley Hai Tung Tan , Christian Wolf , Neelesh Amrutha , Christopher A. Onken , John L. Tonry , Rachel Webster

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

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…

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

The damped random walk (DRW) process is one of the most commonly used and simplest stochastic models to describe variability of active galactic nuclei (AGN). An AGN light curve can be converted to just two DRW model parameters - the signal…

Astrophysics of Galaxies · Physics 2021-09-10 Szymon Kozłowski

The X-ray variability of the Active Galactic Nuclei (AGN) has been most often investigated with studies of individual, nearby, sources, and only a few ensemble analyses have been applied to large samples in wide ranges of luminosity and…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-21 F. Vagnetti , S. Turriziani , D. Trevese

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

We investigate the relationship between AGN optical variability timescales, amplitudes, and supermassive black hole (SMBH) masses using homogeneous light curves from the All-Sky Automated Survey for SuperNovae (ASAS-SN). We fit a damped…

Context. Variability is a ubiquitous feature of active galactic nuclei (AGNs), and the characterisation of the variability is crucial to constrain its physical mechanism and proper applications in AGN studies. The advent of all-sky and…

High Energy Astrophysical Phenomena · Physics 2025-06-04 Heechan Yuk , Xinyu Dai

The $\gamma$-ray astronomy in time domain has been by now progressed further as the variabilities of Active Galactic Nuclei (AGNs) on different timescales have been reported a lot. We study the $\gamma$-ray variabilities of 23 jetted AGNs…

High Energy Astrophysical Phenomena · Physics 2022-05-25 Haiyun Zhang , Dahai Yan , Li Zhang

We use a sample of over 5000 active galactic nuclei (AGN) with extended morphologies at z<0.8 from the Sloan Digital Sky Survey (SDSS) to study the ensemble optical variability as a function of rest-frame time lag and AGN luminosity with…

Astrophysics of Galaxies · Physics 2014-10-01 Unai Gallastegui-Aizpun , Vicki L. Sarajedini

[Abbreviated] We search for scaling relations between the fundamental AGN parameters and rest-frame UV/optical variability properties for a sample of $\sim$90 X-ray selected AGNs covering a wide redshift range from the XMM-COSMOS survey,…

Astrophysics of Galaxies · Physics 2016-01-13 T. Simm , M. Salvato , R. Saglia , G. Ponti , G. Lanzuisi , K. Nandra , R. Bender

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

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

The All Sky Monitor (ASM) onboard the Rossi X-ray Timing Explorer (RXTE) has continuously monitored a number of Active galactic nuclei (AGNs) with similar sampling rates for 14 years from 1996 January to 2009 December. Utilizing the…

High Energy Astrophysical Phenomena · Physics 2015-05-20 You-Hong Zhang

The dependence of the long-term optical/UV variability on the spectral and the fundamental physical parameters for radio-quiet active galactic nuclei (AGNs) is investigated. The multi-epoch repeated photometric scanning data in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Y. L. Ai , W. Yuan , H. Y. Zhou , T. G. Wang , X. -B. Dong , J. G. Wang , H. L. Lu

This work develops application techniques for stochastic modelling of Active Galactic Nuclei (AGN) variability as a probe of accretion disk physics. Stochastic models, specifically Continuous Auto-Regressive Moving Average (CARMA) models,…

Instrumentation and Methods for Astrophysics · Physics 2019-09-06 Jackeline Moreno , Michael S. Vogeley , Gordon T. Richards

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
‹ Prev 1 2 3 10 Next ›