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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

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 study the ensemble X-ray variability properties of Active Galactic Nuclei (AGN) over a large range of timescales (20 ks $\leq T\leq$ 14 yrs), redshift ($0\leq z \lesssim 3$), luminosities ($10^{40}$ erg s$^{-1}\leq L_X\leq 10^{46}$ erg…

High Energy Astrophysical Phenomena · Physics 2023-05-10 M. Paolillo , I. E. Papadakis , W. N. Brandt , F. E. Bauer , G. Lanzuisi , V. Allevato , O. Shemmer , X. C. Zheng , D. De Cicco , R. Gilli , B. Luo , M. Thomas , P. Tozzi , F. Vito , Y. Q. Xue

We present the type-1 active galactic nuclei (AGN) sample extracted from the VIMOS VLT Deep Survey first observations of 21000 spectra in 1.75 square degree. This sample, which is purely magnitude limited, free of morphological or color…

We study the optical variability characteristics of Active Galactic Nuclei (AGN) from the Swift Burst Alert Telescope (BAT) AGN catalogue by utilising approximately five years of optical light curves from the Zwicky Transient Facility (ZTF)…

High Energy Astrophysical Phenomena · Physics 2025-08-12 Vivek Kumar Jha , Debbijoy Bhattacharya , Hum Chand

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 four-year X-ray all-sky survey (eRASS) of the eROSITA telescope aboard the Spektrum-Roentgen-Gamma satellite will detect ~3 million active galactic nuclei (AGN) with a median redshift of z~1 and a typical luminosity of L_(0.5-2.0 keV) ~…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-29 Alexander Kolodzig , Marat Gilfanov , Gert Hütsi , Rashid Sunyaev

The investigation of emission line regions within active galaxies (AGNs) has a rich and extensive history, now extending to the use of AGNs and quasars as "standardizable" cosmological indicators, shedding light on the evolution of our…

Astrophysics of Galaxies · Physics 2023-11-28 Swayamtrupta Panda , Paola Marziani , Bozena Czerny , Alberto Rodriguez-Ardila , Francisco Pozo Nunez

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…

We study the black hole mass $-$ host galaxy stellar mass relation, $M_{\rm{BH}}-M_{\ast}$, for a sample of 706 $z \lesssim 1.5$ and $i \lesssim 24$ optically-variable active galactic nuclei (AGNs) in three Dark Energy Survey (DES) deep…

Astrophysics of Galaxies · Physics 2025-03-11 Yichen Liu , Colin J. Burke , Diego Miura , Xin Liu , Qian Yang , Priyamvada Natarajan , Charlotte A. Ward

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

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

We present a study of variability time scales in a large sample of Active Galactic Nuclei at several frequencies between 4.8 and 230 GHz. We investigate the differences of various AGN types and frequencies and correlate the measured time…

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

We investigate the multi-wavelength properties of host galaxies of 3701 X-ray-selected active galactic nuclei (AGNs) out to z~5 in the Chandra-COSMOS Legacy Survey. Thanks to the extensive multi-wavelength photometry available in the COSMOS…

Studying the morphology of a large sample of active galaxies at different wavelengths and comparing it with active galactic nuclei (AGN) properties, such as black hole mass ($M_{BH}$) and Eddington ratio ($\lambda_{Edd}$), can help us in…

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

Variability is a fundamental signature for active galactic nuclei (AGN) activity, and serve as an unbiased indicator for rapid instability happened near the center supermassive black hole (BH). Previous studies showed that AGN variability…

Astrophysics of Galaxies · Physics 2024-12-09 Wei Leong Tee , Xiaohui Fan , Feige Wang , Jinyi Yang

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

Variability of active galactic nuclei (AGNs) has long been servicing as an essential avenue of exploring the accretion physics of black hole (BH). There are two commonly used methods for analyzing AGN variability. First, the AGN…

Astrophysics of Galaxies · Physics 2024-07-04 Zhen-Bo Su , Zhen-Yi Cai , Mouyuan Sun , Hengxiao Guo , Wei-Min Gu , Jun-Xian Wang