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The Vera C. Rubin Observatory LSST is expected to discover tens of millions of new Active Galactic Nuclei (AGNs). The survey's exceptional cadence and sensitivity will enable UV/optical/NIR monitoring of a significant fraction of these…

The correlation observed between monochromatic X-ray and UV luminosities in radiatively-efficient active galactic nuclei (AGN) lacks a clear theoretical explanation despite being used for many applications. Such a correlation, with its…

High Energy Astrophysical Phenomena · Physics 2019-08-21 Riccardo Arcodia , Andrea Merloni , Kirpal Nandra , Gabriele Ponti

The X-ray properties of Active Galactic Nuclei (AGNs) depend on their underlying physical parameters, particularly the accretion rate. We identified eight reverberation-mapped AGNs with some of the largest known accretion rates without…

High Energy Astrophysical Phenomena · Physics 2024-01-17 Jaya Maithil , Michael S. Brotherton , Ohad Shemmer , Bin Luo , Pu Du , Jian-Min Wang , Hu Chen , Sarah C. Gallagher , Yan-Rong Li , Rodrigo S. Nemmen

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

Multiple models have been suggested over the years to explain the structure and support of accretion disks around supermassive black holes, from the standard thin thermal-pressure-dominated $\alpha$-disk model to more recent models that…

High Energy Astrophysical Phenomena · Physics 2026-04-28 Yashvardhan Tomar , Philip F. Hopkins , Kyle Kremer

Time series data analytics has been a problem of substantial interests for decades, and Dynamic Time Warping (DTW) has been the most widely adopted technique to measure dissimilarity between time series. A number of global-alignment kernels…

Machine Learning · Computer Science 2018-09-17 Lingfei Wu , Ian En-Hsu Yen , Jinfeng Yi , Fangli Xu , Qi Lei , Michael Witbrock

The radius-luminosity (R-L) relationship of active galactic nuclei (AGNs) established by the reverberation mapping (RM) observations has been widely used as a single-epoch black hole mass estimator in the research of large AGN samples.…

Astrophysics of Galaxies · Physics 2020-01-08 Pu Du , Jian-Min Wang

We present and analyse quasi-simultaneous multi-epoch spectral energy distributions (SEDs) of seven reverberation-mapped AGNs for which accurate black hole mass measurements and suitable archival data are available from the 'AGN Watch'…

Astrophysics of Galaxies · Physics 2017-12-27 Ece Kilerci-Eser , Marianne Vestergaard

In this study, we demonstrate some of the caveats in common statistical methods used for analysing astronomical variability timescales. We consider these issues specifically in the context of active galactic nuclei (AGNs) and use a more…

Astrophysics of Galaxies · Physics 2024-12-12 Sofia Kankkunen , Merja Tornikoski , Talvikki Hovatta

The bulk of X-ray spectroscopic studies of active galactic nuclei (AGN) are focused on local ($z < 0.1$) sources with low-to-moderate ($< 0.3$) Eddington ratio ($\lambda_\mathrm{Edd}$). It is then mandatory to overcome this limitation and…

Astrophysics of Galaxies · Physics 2023-04-03 M. Laurenti , F. Tombesi , F. Vagnetti , E. Piconcelli , M. Guainazzi , R. Middei

The spectral energy distribution (SED) of low-luminosity active galactic nuclei (LLAGN) presents challenges due to their faint emissions and the complexity of their accretion processes. This study introduces a new CIGALE module tailored for…

There are strong suggestions that the disk-like accretion flow onto massive black hole in AGN is disrupted in its innermost part (10-100 Rg), possibly due to the radiation pressure instability. It may form a hot optically thin quasi…

Astrophysics · Physics 2009-10-31 B. Czerny , A. Abrassart , S. Collin-Souffrin , A. -M. Dumont

Among the most extreme objects in the Universe, active galactic nuclei (AGN) are luminous centers of galaxies where a black hole feeds on surrounding matter. The variability patterns of the light emitted by an AGN contain information about…

Instrumentation and Methods for Astrophysics · Physics 2021-06-22 Ji Won Park , Ashley Villar , Yin Li , Yan-Fei Jiang , Shirley Ho , Joshua Yao-Yu Lin , Philip J. Marshall , Aaron Roodman

The James Webb Space Telescope (JWST) observations enable the exploration of active galactic nuclei (AGNs) with broad-line emission in the early universe. Despite their clear radiative and morphological signatures of AGNs in rest-frame…

High Energy Astrophysical Phenomena · Physics 2025-05-15 Kohei Inayoshi , Shigeo S. Kimura , Hirofumi Noda

With the advancement of technology, machine learning-based analytical methods have pervaded nearly every discipline in modern studies. Particularly, a number of methods have been employed to estimate the redshift of gamma-ray loud active…

High Energy Astrophysical Phenomena · Physics 2023-12-13 Sarvesh Gharat , Abhimanyu Borthakur , Gopal Bhatta

Aims: We investigate the suitability of {\alpha}-viscosity in self-similar models for self-gravitating disks with a focus on active galactic nuclei (AGN) disks. Methods: We use a self-similar approach to simplify the partial differential…

High Energy Astrophysical Phenomena · Physics 2016-03-16 Marcus Kubsch , T. F. Illenseer , W. J. Duschl

The UV/optical variability of AGN has long been thought to be driven by the X-ray illumination of the accretion disk. However, recent multi-wavelength campaigns of nearby Seyfert galaxies seem to challenge this paradigm, with an apparent…

Astrophysics of Galaxies · Physics 2022-08-31 Christos Panagiotou , Iossif Papadakis , Erin Kara , Elias Kammoun , Michal Dovčiak

Context: Variations in the mass accretion rate appear to be responsible for the rapid transitions in spectral type that are observed in increasingly more active galactic nuclei (AGNs). These objects are now labeled "changing-look" AGNs and…

Astrophysics of Galaxies · Physics 2020-04-15 F. Marin , D. Hutsemékers

We report that moderately eccentric flows around supermassive black holes (SMBHs), formed via either circumnuclear gas accretion or tidal disruption events, generate eccentricity cascades (from >0.8 to 0.2 outward), explaining…

Astrophysics of Galaxies · Physics 2026-03-31 Hongping Deng

The long term X-ray spectral variability of ten active galactic nuclei (AGN) shows a positive spectral index-flux correlation for each object (Sobolewska & Papadakis 2009). An inner advection dominated accretion flow (ADAF) may connect to a…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Xinwu Cao , Jun-Xian Wang