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Related papers: The ensemble optical variability of type-1 AGN in …

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We present the results from a study of ~9,600 Broad-Line selected AGN with host galaxies detected from the Sloan Digital Sky Survey Data Release 17 (SDSS DR17). We compute ensemble variability statistics based on the comparison of the…

Astrophysics of Galaxies · Physics 2024-05-24 Krittapas Chanchaiworawit , Vicki Sarajedini

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

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

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 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 the properties of the ensemble variability $V$ for nearly 5000 near-infrared (NIR) AGNs selected from the catalog of Quasars and Active Galactic Nuclei (13th Ed.) and the SDSS-DR7 quasar catalog. From 2MASS, DENIS, and UKIDSS/LAS…

Astrophysics of Galaxies · Physics 2015-06-03 Shinjirou Kouzuma , Hitoshi Yamaoka

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

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 study variability of active galactic nuclei (AGNs) by using the deep optical multiband photometry data obtained from the Hyper Suprime-Cam Subaru Strategic Program (HSC SSP) survey in the COSMOS field. The images analyzed here were taken…

Astrophysics of Galaxies · Physics 2020-05-13 Yuki Kimura , Toru Yamada , Mitsuru Kokubo , Naoki Yasuda , Tomoki Morokuma , Tohru Nagao , Yoshiki Matsuoka

The variability of the X-ray spectra of active galactic nuclei (AGN) usually includes a change of the spectral slope. This has been investigated for a small sample of local AGNs by Sobolewska and Papadakis, who found that slope variations…

Astrophysics of Galaxies · Physics 2016-03-23 Roberto Serafinelli , Fausto Vagnetti , Riccardo Middei

Most investigations of the X-ray variability of active galactic nuclei (AGN) have been concentrated on the detailed analyses of individual, nearby sources. A relatively small number of studies have treated the ensemble behaviour of the more…

Astrophysics of Galaxies · Physics 2016-09-21 F. Vagnetti , R. Middei , M. Antonucci , M. Paolillo , R. Serafinelli

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

[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

Most of the variability studies of active galactic nuclei (AGNs) are based on ensemble analyses. Nevertheless, it is interesting to provide estimates of the individual variability properties of each AGN, in order to relate them with…

Astrophysics of Galaxies · Physics 2020-11-17 M. Laurenti , F. Vagnetti , R. Middei , M. Paolillo

The ensemble optical/ultraviolet variability of narrow-line Seyfert 1 (NLS1) type active galactic nuclei (AGNs) is investigated, based on a sample selected from the Sloan Digital Sky Survey (SDSS) Stripe-82 region with multi-epoch…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Y. L. Ai , W. Yuan , H. Zhou , T. G. Wang , X. -B. Dong , J. G. Wang , H. L. Lu

In a previous paper (Gavignaud et al. 2006), we presented the type-1 Active Galactic Nuclei (AGN) sample obtained from the first epoch data of the VIMOS-VLT Deep Survey (VVDS). The sample consists of 130 faint, broad-line AGN with redshift…

The Active Galactic Nuclei (AGN) glossary is vast and complex. Depending on selection method, observing wavelength, and brightness, AGNs are assigned distinct labels, yet the relationship between different selection methods and the…

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

Variability in the X-rays is a key ingredient in understanding and unveiling active galactic nuclei (AGN) properties. In this band flux variations occur on short time scales (hours) as well as on larger times scales. While short time scale…

High Energy Astrophysical Phenomena · Physics 2017-03-08 R. Middei , F. Vagnetti , S. Bianchi , F. La Franca , M. Paolillo , F. Ursini

Low luminosity active galactic nuclei (LLAGN) probe accretion physics in the low Eddington regime and can provide additional clues about galaxy evolution. AGN variability is ubiquitous and thus provides a reliable tool for finding AGN. We…

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