English
Related papers

Related papers: The relation between the optical variability times…

200 papers

A long-term variability study spanning a range of black hole mass systems, from microquasars hosting stellar-mass black holes to active galactic nuclei (AGNs) harboring supermassive black holes, provides new insights into the physics of…

High Energy Astrophysical Phenomena · Physics 2026-04-20 Yongyun Chen , Qiusheng Gu , Junhui Fan , Dingrong Xiong , Xiaoling Yu , Xiaogu Zhong , Xiaotong Guo

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

The variability mechanisms from jetted AGNs are still under debate. Here the damped random walk (DRW) model, implemented through Gaussian Processe (GPs), is used to fit the $ZTF$ long-term optical light curves of 1684 $\gamma$-ray emission…

The long-term variability study over a range of black hole (BH) mass systems from the microquasars of stellar-mass black holes to the Active Galactic Nuclei (AGNs) of supermassive black holes, in $\gamma$-rays offers new insights into the…

High Energy Astrophysical Phenomena · Physics 2024-10-10 Ajay Sharma , Raj Prince , Debanjan Bose

We compiled a sample of 73 active galactic nuclei (AGNs) with reverberation mapping (RM) observations from RM campaigns including our ongoing campaign of monitoring super-Eddington accreting massive black holes (SEAMBHs). This sample covers…

Here we investigate the connection of broad emission line shapes and continuum light curve variability time scales of type-1 Active Galactic Nuclei (AGN). We developed a new model to describe optical broad emission lines as an accretion…

Astrophysics of Galaxies · Physics 2018-05-21 E. Bon , P. Jovanovic , P. Marziani , N. Bon , A. Otasevic

Accretion disks around supermassive black holes in active galactic nuclei produce continuum radiation at ultraviolet and optical wavelengths. Physical processes in the accretion flow lead to stochastic variability of this emission on a wide…

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…

The spin of supermassive black holes could power jets from active galactic nuclei (AGN), although direct observational evidence for this conjecture is sparse. The accretion disk luminosity and jet power, on the other hand, have long been…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Sjoert van Velzen , Heino Falcke

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

We use a sample of radio-loud active galactic nuclei (AGNs) with measured black hole masses to explore the jet formation mechanisms in these sources. Based on the K\"{o}nigl's inhomogeneous jet model, the jet parameters, such as the bulk…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Bo Chai , Xinwu Cao , Minfeng Gu

The theoretical model suggests that relativistic jets of AGN rely on the black hole spin and/or accretion. We study the relationship between jet, accretion, and spin using supermassive black hole samples with reliable spin of black holes.…

High Energy Astrophysical Phenomena · Physics 2024-10-11 Yongyun Chen , Qiusheng Gu , Jianghe Yang , Junhui Fan , Xiaoling Yu , Dingrong Xiong , Nan Ding , Xiaotong Guo

We investigate how magnetic field variations around accreting black holes on event horizon scales affect the morphology of magnetically-driven jet on larger scales. By performing radiative transfer calculations on general relativistic…

High Energy Astrophysical Phenomena · Physics 2025-03-24 Yuh Tsunetoe , Ramesh Narayan , Angelo Ricarte

The Fundamental Plane (FP) of Black Hole (BH) Activity in galactic nuclei relates X-ray and radio luminosities to BH mass and accretion rate. However, there is a large scatter exhibited by the data, which motivated us for a new variable. We…

High Energy Astrophysical Phenomena · Physics 2020-05-06 Caner Unal , Abraham Loeb

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

Analysing the long-term radio variability of active galactic nuclei (AGNs) is essential to understanding the physics of relativistic jets launched by supermassive black holes. We aim to connect the characteristic timescales obtained from a…

Astrophysics of Galaxies · Physics 2026-05-07 Sofia Kankkunen , Merja Tornikoski , Talvikki Hovatta

We use the observed jet boundary transition from parabolic to conical shape, which was earlier discovered as possibly a common effect in active galactic nuclei, to estimate a black hole, a jet and an ambient medium parameters. We explained…

High Energy Astrophysical Phenomena · Physics 2020-09-23 E. E. Nokhrina , Y. Y. Kovalev , A. B. Pushkarev

Over the last 12 years, AGN monitoring by RXTE, has revolutionised our understanding of the X-ray variability of AGN, of the relationship between AGN and Galactic black hole X-ray binaries (BHBs) and hence of the accretion process itself,…

High Energy Astrophysical Phenomena · Physics 2014-11-20 I. M. McHardy

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

Warped accretion discs in Active Galactic Nuclei (AGN) exert a torque on the black hole that tends to align the rotation axis with the angular momentum of the outer disc. We compute the magnitude of this torque by solving numerically for…

Astrophysics · Physics 2009-10-31 Priyamvada Natarajan , Philip J. Armitage
‹ Prev 1 2 3 10 Next ›