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The spectra of Active Galactic Nuclei (AGNs) are often characterized by a wealth of emission lines with different profiles and intensity ratios that led to a complicated classification. Their electro-magnetic radiation spans more than 10…

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

One of the important and widely used classes of models for non-Gaussian time series is the generalized autoregressive model average models (GARMA), which specifies an ARMA structure for the conditional mean process of the underlying time…

Methodology · Statistics 2021-05-13 Tingguo Zheng , Han Xiao , Rong Chen

Active galactic nuclei (AGN) have been studied as alternate probes in cosmology due to their large and stable luminosities and broad redshift range. Previously it was shown that higher-redshift AGN that were reverberation-mapped (RM) using…

Astrophysics of Galaxies · Physics 2025-12-16 Shulei Cao , Amit Kumar Mandal , Michal Zajaček , Bharat Ratra

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

Dislocation mobility, which dictates the response of dislocations to an applied stress, is a fundamental property of crystalline materials that governs the evolution of plastic deformation. Traditional approaches for deriving mobility laws…

High cadence, high quality observations of active galactic nuclei (AGN) clearly show continuum variations with lags, relative to the shortest observed variable UV continuum, that increase with wavelength ("lag spectra"). These have been…

Astrophysics of Galaxies · Physics 2021-11-17 Hagai Netzer

Theory of random processes provides an attractive mathematical tool to describe the fluctuating signal from accreting sources, such as active galactic nuclei and Galactic black holes observed in X-rays. These objects exhibit featureless…

Astrophysics · Physics 2008-08-11 T. Pechacek , V. Karas , B. Czerny

The scenario of variations in accreting process around central black hole has been widely accepted as the preferred physical origin of changing-look active galactic nuclei (CLAGN), rather than obscuration effects by moving dust clouds. In…

Astrophysics of Galaxies · Physics 2026-04-30 Zhang XueGuang

The spatial clustering of active galactic nuclei (AGNs) is considered to be one of the important diagnostics for the understanding of the underlying processes behind their activities complementary to measurements of the luminosity function…

In a series of papers based on the FIRST and Sloan Digital Sky Surveys (SDSS), we investigate the local population of star-forming galaxies and Active Galactic Nuclei (AGN) in order to clarify the link between these two types of activity,…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-25 Pietro M. Reviglio , David J. Helfand

In this paper, we propose a novel variable selection approach in the framework of sparse high-dimensional GLARMA models. It consists in combining the estimation of the autoregressive moving average (ARMA) coefficients of these models with…

Statistics Theory · Mathematics 2019-10-14 Céline Lévy-Leduc , Sarah Ouadah , Laure Sansonnet

Locally interacting dynamical systems, such as epidemic spread, rumor propagation through crowd, and forest fire, exhibit complex global dynamics originated from local, relatively simple, and often stochastic interactions between dynamic…

Systems and Control · Electrical Eng. & Systems 2024-05-29 Beomseok Kang , Harshit Kumar , Minah Lee , Biswadeep Chakraborty , Saibal Mukhopadhyay

Non-spherical particles transported by an anisotropic turbulent flow preferentially align with the mean shear and intermittently tumble when the local strain fluctuates. Such an intricate behaviour is here studied for inertialess,…

Soft Condensed Matter · Physics 2022-12-27 Lorenzo Campana , Mireille Bossy , Jeremie Bec

Accretion discs around black holes power some of the most luminous objects in the Universe. Discs that are misaligned to the black hole spin can become warped over time by Lense-Thirring precession. Recent work has shown that strongly…

High Energy Astrophysical Phenomena · Physics 2021-03-17 Anagha Raj , Chris Nixon

Active galactic nucleus (AGN) emission is dominated by stochastic, aperiodic variability which overwhelms any periodic/quasi-periodic signal (QPO) if one is present. The Auto Correlation Function (ACF) and Phase Dispersion Minimization…

High Energy Astrophysical Phenomena · Physics 2021-10-28 S. Krishnan , A. G. Markowitz , A. Schwarzenberg-Czerny , M. J. Middleton

According to the standard paradigm, the strong and compact luminosity of active galactic nuclei (AGN) is due to multi-temperature black body emission originating from an accretion disk formed around a supermassive black hole. This central…

Astrophysics of Galaxies · Physics 2016-10-18 P. Andrea Rojas Lobos , Rene W. Goosmann , Frederic Marin

We present a probabilistic cross-correlation approach to estimate time delays in the context of reverberation mapping (RM) of Active Galactic Nuclei (AGN). We reformulate the traditional interpolated cross-correlation method as a…

Instrumentation and Methods for Astrophysics · Physics 2023-06-07 F. Pozo Nuñez , N. Gianniotis , K. L. Polsterer

We present an analysis of 10 ks snapshot Chandra observations of 12 shocked post-starburst galaxies, which provide a window into the unresolved question of active galactic nuclei (AGN) activity in post-starburst galaxies and its role in the…

Modern power systems with high penetration of inverter-based resources exhibit complex dynamic behaviors that challenge the scalability and generalizability of traditional stability assessment methods. This paper presents a dynamic…

Systems and Control · Electrical Eng. & Systems 2025-11-18 Guang An Ooi , Otavio Bertozzi , Mohd Asim Aftab , Charalambos Konstantinou , Shehab Ahmed