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Related papers: Variability-selected low luminosity AGNs in the SA…

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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

Obtaining a census of active galactic nuclei (AGN) activity across cosmic time is critical to our understanding of galaxy evolution and formation. Many AGN classification techniques are compromised by dust obscuration. However, very long…

Astrophysics of Galaxies · Physics 2021-05-12 J. F. Radcliffe , P. D. Barthel , A. P. Thomson , M. A. Garrett , R. J. Beswick , T. W. B. Muxlow

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 identify 85 variable galaxies in the GOODS North and South fields using 5 epochs of HST ACS V-band (F606W) images spanning 6 months. The variables are identified through significant flux changes in the galaxy's nucleus and represent ~2%…

Astrophysics of Galaxies · Physics 2015-05-27 Vicki L. Sarajedini , David C. Koo , Alison J. Klesman , Elise S. Laird , Pablo G. Perez Gonzalez , Mark Mozena

Aims: Active Galactic Nuclei are known to be variable throughout the electromagnetic spectrum. An energy domain poorly studied in this respect is the hard X-ray range above 20 keV. Methods: The first 9 months of the Swift/BAT all-sky survey…

We conduct an analysis of over 60,000 dwarf galaxies (7<=log(M_*/M_\odot)<=10) in search of photometric variability indicative of active galactic nuclei (AGNs). Using data from the Young Supernova Experiment (YSE), a time domain survey on…

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

Optical variability has proven to be an effective way of detecting AGNs in imaging surveys, lasting from weeks to years. In the present work we test its use as a tool to identify AGNs in the VST multi-epoch survey of the COSMOS field,…

Low-luminosity Active Galactic Nuclei (LLAGN) represent a unique class of AGN in the local universe. Extensive studies of these objects are essential for a comprehensive understanding of jet physics, as past research has largely focused on…

Astrophysics of Galaxies · Physics 2025-03-13 Xi Yan , Ru-Sen Lu

A majority of the active galactic nuclei (AGN) in the local Universe are classified as low-luminosity AGN (LLAGN), having bolometric luminosities $\lesssim 10^{42} \ \mathrm{erg \ s^{-1}}$. Although high-energy gamma-ray emission is…

High Energy Astrophysical Phenomena · Physics 2026-04-08 Chris Karwin , Nikita Khatiya , Margot Boughelilba , Xiurui Zhao , Anita Reimer , Marco Ajello

The nature of the obscuring material in active galactic nuclei (AGN) can be studied by measuring changes in the line-of-sight column density, $N_{\rm H,los}$, over time. This can be accomplished by monitoring AGN over long periods of time…

Active galactic nuclei (AGNs) are well-known to exhibit flux variability across a wide range of wavelength regimes, but the precise origin of the variability at different wavelengths remains unclear. To investigate the relatively unexplored…

High Energy Astrophysical Phenomena · Physics 2015-06-24 James R. A. Davenport , John J. Ruan , Andrew C. Becker , Chelsea L. Macleod , Roc M. Cutri

The rapid variability observed in very-high-energy (VHE) sources-such as pulsars, gamma-ray bursts (GRBs), and flares from active galactic nuclei (AGN)-can be used to detect or constrain a potential violation of Lorentz invariance (LIV).…

High Energy Astrophysical Phenomena · Physics 2026-04-14 Cyann Plard , Sami Caroff , the CTAO-LST project

Observations and theoretical simulations suggest that the large scale environment plays a significant role in how galaxies form and evolve and, in particular, whether and when galaxies host an actively accreting supermassive black hole in…

Astrophysics of Galaxies · Physics 2025-07-16 Anish S. Aradhey , Anca Constantin , Michael S. Vogeley , Kelly A. Douglass

The results of Chandra snapshot observations of 11 LINERs (Low-Ionization Nuclear Emission-line Regions), three low-luminosity Seyfert galaxies, and one HII-LINER transition object are presented. Our sample consists of all the objects with…

Astrophysics · Physics 2010-04-06 Yuichi Terashima , Andrew S. Wilson

X-ray variability is very common in active galactic nuclei (AGN), but these variations may not occur similarly in different families of AGN. We aim to disentangle the structure of low ionization nuclear emission line regions (LINERs)…

Astrophysics of Galaxies · Physics 2016-06-15 Lorena Hernandez-Garcia , Josefa Masegosa , Omaira Gonzalez-Martin , Isabel Marquez , Jaime Perea

The variability of active galactic nuclei (AGNs) is ubiquitous but has not yet been understood. Measuring the optical variation properties of AGNs, such as variation timescale and amplitude, and then correlating them with their fundamental…

Astrophysics of Galaxies · Physics 2024-01-11 Xu-Fan Hu , Zhen-Yi Cai , Jun-Xian Wang

We study the properties of the host galaxies of Changing-Look Active Galactic Nuclei (CL AGNs) with the aim of understanding the conditions responsible for triggering CL activity. We find that CL AGN hosts primarily reside in the so-called…

Astrophysics of Galaxies · Physics 2021-03-17 Sierra A. Dodd , Jamie A. P. Law-Smith , Katie Auchettl , Enrico Ramirez-Ruiz , Ryan J. Foley

We present an estimate of the space density of Active Galactic Nuclei (AGN) at z=3. Combining deep X-ray data with Lyman Break Galaxy (LBG) colour-selection in the rest-frame UV makes for highly efficient identification of AGN in a narrow…

Astrophysics · Physics 2009-11-10 K. Nandra , E. S. Laird , C. C. Steidel

We present a multi wavelength analysis of 28 of the most luminous low-redshift narrow-line, ultra-hard X-ray selected active galactic nuclei (AGN) drawn from the 70 month Swift/BAT all-sky survey, with bolometric luminosities of…