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Related papers: Microvariability in AGNs: study of different stati…

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Modern X-ray telescopes have detected hundreds of thousands of X-ray sources in the universe. However, current methods to classify these sources using the X-ray data themselves suffer problems - detailed X-ray spectroscopy of individual…

High Energy Astrophysical Phenomena · Physics 2023-04-04 Pavan R. Hebbar , Craig O. Heinke

We are conducting an archival Swift program to measure multiwavelength variability in active galactic nuclei (AGN). This variability information will provide constraints on the geometry, physical conditions and processes of the structures…

High Energy Astrophysical Phenomena · Physics 2015-05-21 Jonathan Gelbord , Caryl Gronwall , Dirk Grupe , Dan Vanden Berk , Jian Wu

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

X-ray variability is a well-established characteristic of active galactic nuclei (AGN), known to correlate inversely with both the supermassive black hole mass and luminosity, although the degree of each remains a topic of debate. The…

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

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

We present the first short time-scale ($\sim$hours to days) optical variability study of a large sample of Active Galactic Nuclei (AGN) observed with the Kepler/K2 mission. The sample contains 252 AGN observed over four campaigns with $\sim…

High Energy Astrophysical Phenomena · Physics 2018-03-14 E. Aranzana , E. Kording , P. Uttley , S. Scaringi , S. Bloemen

We present an optical variability analysis and comparison of the samples of Seyfert 1 and 2 galaxies, selected from the \textit{Swift} 9-month BAT catalog, using the light curves from Transiting Exoplanet Survey Satellite (TESS) and All-Sky…

We analyze Hubble Space Telescope (HST) optical imaging of eight low-mass galaxies hosting active galactic nuclei (AGN) identified via their photometric variability in \cite{baldassare_search_2020}. We use GALFIT to model the 2D galaxy…

Astrophysics of Galaxies · Physics 2025-02-06 Erin Kimbro , Vivienne Baldassare , Guy Worthey , Marla Geha , Jenny Greene

The unification of active galactic nuclei (AGN) is a model that has been difficult to test due to the lack of knowledge on the intrinsic luminosities of the objects. We present a test were we probe the model by statistical investigation of…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-05 Beatriz Villarroel , Andreas Korn , Yoshiki Matsuoka

Active galactic nuclei (AGN) are known for irregular variability on all time scales, down to intra-day variability with relative variations of a few percent within minutes to hours. On such short timescales, unexplored territory, such as…

Astrophysics of Galaxies · Physics 2015-11-27 Taeseok Lee , Sascha Trippe , Junghwan Oh , Do-Young Byun , Bong-Won Sohn , Sang-Sung Lee

Variability is one of the classic features of active galactic nuclei (AGNs). The normalized structure function was applied to distinguish variability samples from OVRO, ASAS-SN and Fermi. A power-law function model was selected to fit the…

High Energy Astrophysical Phenomena · Physics 2026-03-23 Xuan Wei , Jie Tang , Yu Tao

The aim of this paper is to describe new statistical methods for determination of the correlations among and distributions of physical parameters from a multivariate data with general and arbitrary truncations and selection biases. These…

Astrophysics · Physics 2007-05-23 Vahe' Petrosian

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

We study the optical variability of a sample of candidate low-mass (dwarf ang Seyfert) active galactic nuclei (AGNs) using Zwicky Transient Facility g-band light curves. Our sample is compiled from broad-line AGNs in dwarf galaxies reported…

Astrophysics of Galaxies · Physics 2023-04-11 Z. Franklin Wang , Colin J. Burke , Xin Liu , Yue Shen

We present the analysis of multiepoch observations of a set of 12 variable, Compton-thin, local (z<0.1) active galactic nuclei (AGN) selected from the 100-month BAT catalog. We analyze all available X-ray data from \chandra, \xmm, and…

Astrophysics of Galaxies · Physics 2023-10-18 N. Torres-Albà , S. Marchesi , X. Zhao , I. Cox , A. Pizzetti , M. Ajello , R. Silver

Recent surveys monitoring millions of light curves of resolved stars in the LMC have discovered several microlensing events. Unresolved stars could however significantly contribute to the microlensing rate towards the LMC. Monitoring…

Astrophysics · Physics 2009-10-30 A. -L. Melchior

We extend the work developed in previous papers on microlensing with a selection of variable stars. We use the Pixel Method to select variable stars on a set of 2.5 x 10**6 pixel light curves in the LMC Bar presented elsewhere. The previous…

Astrophysics · Physics 2009-11-06 A. -L. Melchior , S. M. G. Hughes , J. Guibert

We study the properties of 975 active galactic nuclei (AGN) selected by variability in the Pan-STARRS1 Medium-Deep Survey. Using complementary multi wavelength data from the ultraviolet to the far-infrared, we use SED fitting to determine…

Astrophysics of Galaxies · Physics 2016-07-27 S. Heinis , S. Gezari , S. Kumar , W. S. Burgett , H. Flewelling , M. E. Huber , N. Kaiser , R. J. Wainscoat , C. Waters

The spectral variability of active galactic nuclei (AGN) is one of their key features that enables us to study in more details the structure of AGN emitting regions. Especially, the broad line profiles, that vary both in flux and shape,…

Astrophysics of Galaxies · Physics 2016-01-20 D. Ilic , L. C. Popovic , A. I. Shapovalova , A. N. Burenkov , V. H. Chavushyan , A. Kovacevic