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Context. The classification of active galactic nuclei (AGNs) is a challenge in astrophysics. Variability features extracted from light curves offer a promising avenue for distinguishing AGNs and their subclasses. This approach would be very…

Previous studies of the active galactic nuclei (AGN) contribution to the cosmic X-ray background (CXB) consider only observable parameters such as luminosity and absorbing column. Here, for the first time, we extend the study of the CXB to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 A. R. Draper , D. R. Ballantyne

We present a phenomenological forward Monte Carlo model for forecasting the population of active galactic nuclei (AGNs) in dwarf galaxies observable via their optical variability. Our model accounts for expected changes in the spectral…

Astrophysics of Galaxies · Physics 2023-08-14 Colin J. Burke , Yue Shen , Xin Liu , Priyamvada Natarajan , Neven Caplar , Jillian M. Bellovary , Z. Franklin Wang

The time lag between optical and near-infrared continuum emission in active galactic nuclei (AGN) shows a tight correlation with luminosity and has been proposed as a standardisable candle for cosmology. In this paper, we explore the use of…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-12 S. F. Hönig , D. Watson , M. Kishimoto , P. Gandhi , M. Goad , K. Horne , F. Shankar , M. Banerji , B. Boulderstone , M. Jarvis , M. Smith , M. Sullivan

Over the next ten years, the Vera C.\ Rubin Observatory (VRO) will observe $\sim$10 million active galactic nuclei (AGN) with a regular and high cadence. During this time, the intensities of most of these AGN will fluctuate stochastically.…

Astrophysics of Galaxies · Physics 2022-12-20 Cyril Creque-Sarbinowski , Marc Kamionkowski , Bei Zhou

One of the most peculiar characteristics of Active Galactic Nuclei (AGN) is their variability over all wavelengths. This property has been used in the past to select AGN samples and is foreseen to be one of the detection techniques applied…

We use the VST-COSMOS survey to identify, via their optical broadband variability, 30 AGN in nearby (z<0.4) dwarf (10^8 MSun < M < 10^10 MSun) galaxies. VST-COSMOS offers a 1 deg^2 survey footprint, a single visit depth of 24.6 mag and 68…

Astrophysics of Galaxies · Physics 2025-11-20 S. Kaviraj , D. De Cicco , I. Lazar , B. Bichang'a , A. E. Watkins , G. Martin , S. Koudmani

We searched the Northern Hemisphere Fields of the GALEX Time-Domain Survey (TDS) for galaxies with UV variability indicative of active galactic nuclei (AGNs). We identified 48 high-probability candidate AGNs from a parent sample of 1819…

Astrophysics of Galaxies · Physics 2024-05-31 Erik J. Wasleske , Vivienne F. Baldassare , Christopher M. Carroll

The properties of large-scale galactic outflows, such as their kinetic energy and momentum rates, correlate with the luminosity of the active galactic nucleus (AGN). This is well explained by the wind-driven outflow model, where a fraction…

Astrophysics of Galaxies · Physics 2020-09-30 Kastytis Zubovas , Emanuele Nardini

Physical processes such as re-ignition, enhancement, and fading of active galactic nuclei (AGN) are not entirely understood because the timeline of these events is expected to last many years. However, it is well known that the differences…

Active Galactic Nucleus (AGN) variability can be used to study the physics of the region in the vicinity of the central black hole. In this paper, we investigated intra-night optical variability of AGN in the COSMOS field in order to…

Astrophysics of Galaxies · Physics 2018-09-12 Joonho Kim , Marios Karouzos , Myungshin Im , Changsu Choi , Dohyeong Kim , Hyunsung D. Jun , Joon Hyeop Lee , Mar Mezcua

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

Interband lags in the optical continua of active galactic nuclei (AGN) have been observed over years of monitoring, yet their physical origins remain unclear. While variable interband lags have been found in a few individual AGN…

Astrophysics of Galaxies · Physics 2025-07-08 Zhen-Bo Su , Zhen-Yi Cai , Hengxiao Guo , Mouyuan Sun , Jun-Xian Wang

In this paper we give a brief review of the astrophysics of active galactic nuclei (AGN). After a general introduction motivating the study of AGNs, we discuss our present understanding of the inner workings of the central engines, most…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-18 Henric Krawczynski , Ezequiel Treister

Active Galactic Nuclei (AGN) are axisymmetric systems to first order; their observed properties are likely strong functions of inclination with respect to our line of sight, yet the specific inclinations of all but a few AGN are generally…

Astrophysics of Galaxies · Physics 2015-06-18 T. C. Fischer , D. M. Crenshaw , S. B. Kraemer , H. R. Schmitt , T. J. Turner

The active galactic nuclei (AGN) are among the most powerful sources with an inherent, pronounced and random variation of brightness. The randomness of their time series is so subtle as to blur the border between aperiodic fluctuations and…

Astrophysics of Galaxies · Physics 2020-07-02 Andjelka B Kovacevic , Luka C. Popovic , Dragana Ilic

We perform simulations to study the effects of active galactic nuclei (AGNs) radiation and wind feedback on the properties of slowly rotating accretion flow at parsec scale. We find that when only radiative feedback is considered, outflows…

High Energy Astrophysical Phenomena · Physics 2019-09-11 De-Fu Bu , Xiao-Hong Yang

Large-scale outflows driven by AGNs are an important element of galaxy evolution. Detailed analysis of their properties allows us to probe the activity history of the galactic nucleus and, potentially, other properties of the host galaxy. A…

Astrophysics of Galaxies · Physics 2025-10-17 Kastytis Zubovas , Matas Tartėnas

We studied the Active Galactic Nuclei (AGN) radio emission from a compilation of hard X-ray selected samples, all observed in the 1.4 GHz band. A total of more than 1600 AGN with 2-10 keV de-absorbed luminosities higher than 10^42 erg/s…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 F. La Franca , G. Melini , F. Fiore

The study of morphology in galaxies offers a convenient and quantitative method to measure the shapes and characteristics of galaxy light distribution that reflect the evolutionary history. For AGN-host dwarf galaxies, however, there is a…

Astrophysics of Galaxies · Physics 2025-06-09 Jie Tian , Yinghe Zhao , Xiejin Li , Jinming Bai