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In this work we analyzed X-ray light curves of active galactic nucleus NGC 4051 obtained using Advanced CCD Imaging Spectrometer of Chandra satellite. Taking into account mainly flaring behaviour of AGNs we have used wavelet analysis for…

Astrophysics · Physics 2007-05-23 A. V. Halevin

The Alternating Current Power Flow (ACPF) problem forces a trade-off between the speed of data-driven models and the reliability of analytical solvers. This paper introduces a hybrid framework that synergizes a Graph Neural Network (GNN)…

Systems and Control · Electrical Eng. & Systems 2025-10-28 Mohamed Shamseldein

Graph anomaly detection aims to identify unusual patterns in graph-based data, with wide applications in fields such as web security and financial fraud detection. Existing methods typically rely on contrastive learning, assuming that a…

Machine Learning · Computer Science 2025-05-26 Di Jin , Jingyi Cao , Xiaobao Wang , Bingdao Feng , Dongxiao He , Longbiao Wang , Jianwu Dang

The consequences of complex disturbed environments in the vicinity of a supermassive black hole are not well represented by standard statistical models of optical variability in active galactic nuclei (AGN). Thus, developing new…

A novel method for distributed estimation of the frequency of power systems is introduced based on the cooperation between multiple measurement nodes. The proposed distributed widely linear complex Kalman filter (D-ACKF) and the distributed…

Systems and Control · Computer Science 2014-10-03 Sithan Kanna , Dahir H. Dini , Yili Xia , Ron Hui , Danilo P. Mandic

Analytical templates for the 4-Point Correlation Function (4PCF) covariance matrix have been developed in the past assuming a Gaussian Random Field (GRF). In this work, we present the second part of the beyond GRF calculation of the 4PCF…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-09 William Ortolá Leonard , Zachary Slepian

As one of the important tools for spatial feature extraction, graph convolution has been applied in a wide range of fields such as traffic flow prediction. However, current popular works of graph convolution cannot guarantee spatio-temporal…

Machine Learning · Computer Science 2023-09-15 Tianpu Zhang , Weilong Ding , Mengda Xing

Stellar light curves contain valuable information about oscillations and granulation, offering insights into stars' internal structures and evolutionary states. Traditional asteroseismic techniques, primarily focused on power spectral…

Solar and Stellar Astrophysics · Physics 2024-01-19 Jia-Shu Pan , Yuan-Sen Ting , Jie Yu

We construct a holographic effective superconducting theory by considering a special gauge-axion higher derivative term. The gauge-axion coupling results in the transport behavior similar to the vortex response in the dual boundary field…

High Energy Physics - Theory · Physics 2022-06-08 Yan Liu , Xi-Jing Wang , Jian-Pin Wu , Xin Zhang

In this paper, we extend the paraxial conical refraction model to the case of the partially coherent light using the unified optical coherence theory. We demonstrate the decomposition of conical refraction correlation functions into…

Optics · Physics 2022-05-12 V. Yu. Mylnikov , V. V. Dudelev , E. U. Rafailov , G. S. Sokolovskii

To characterize temporal correlations in temporal networks, we define an autocorrelation function (ACF) for temporal networks in terms of the similarity between two snapshot networks separated by a certain time interval. By employing a…

Physics and Society · Physics 2024-08-14 Hang-Hyun Jo

The scarce optical variability studies in spectrally classified Type 2 active galactic nuclei (AGNs) have led to the discovery of anomalous objects that are incompatible with the simplest unified models (UM). This paper focuses on the…

Astrophysics of Galaxies · Physics 2022-11-08 E. López-Navas , P. Arévalo , S. Bernal , Matthew J. Graham , L. Hernández-García , P. Lira , P. Sánchez-Sáez

We present a method enabling the creation of constant-uncertainty/constant-significance light curves with the data of the Fermi-Large Area Telescope (LAT). The adaptive-binning method enables more information to be encapsulated within the…

High Energy Astrophysical Phenomena · Physics 2015-06-03 B. Lott , L. Escande , S. Larsson , J. Ballet

This paper presents a new optical system for detecting light signals associated with the change in incoming photon number. The system employs quantum correlation of photon pairs created via spontaneous parametric down-conversion (SPDC). The…

High Energy Physics - Experiment · Physics 2020-10-27 Phuong Hoang Le , Binh Xuan Cao

To fully understand cosmic black hole growth we need to constrain the population of heavily obscured active galactic nuclei (AGN) at the peak of cosmic black hole growth ($z\sim$1-3). Sources with obscuring column densities higher than…

High Energy Astrophysical Phenomena · Physics 2017-08-02 L. Baronchelli , M. Koss , K. Schawinski , C. Cardamone , F. Civano , A. Comastri , M. Elvis , G. Lanzuisi , S. Marchesi , C. Ricci , M. Salvato , B. Trakhtenbrot , E. Treister

Graph convolution is the core of most Graph Neural Networks (GNNs) and usually approximated by message passing between direct (one-hop) neighbors. In this work, we remove the restriction of using only the direct neighbors by introducing a…

Social and Information Networks · Computer Science 2022-04-06 Johannes Gasteiger , Stefan Weißenberger , Stephan Günnemann

Identification of anomalous light curves within time-domain surveys is often challenging. In addition, with the growing number of wide-field surveys and the volume of data produced exceeding astronomers ability for manual evaluation,…

Instrumentation and Methods for Astrophysics · Physics 2020-09-30 Sara Webb , Michelle Lochner , Daniel Muthukrishna , Jeff Cooke , Chris Flynn , Ashish Mahabal , Simon Goode , Igor Andreoni , Tyler Pritchard , Timothy M. C. Abbott

Cross-frequency coupling (CFC) has been proposed to coordinate neural dynamics across spatial and temporal scales. Despite its potential relevance for understanding healthy and pathological brain function, the standard CFC analysis and…

Neurons and Cognition · Quantitative Biology 2014-10-08 Juhan Aru , Jaan Aru , Viola Priesemann , Michael Wibral , Luiz Lana , Gordon Pipa , Wolf Singer , Raul Vicente

Ongoing and future spectroscopic galaxy surveys will cover unprecedented volumes with a number of objects large enough to effectively probe clustering anisotropies through higher-order statistics. In this work, we present a novel and…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-19 Antonio Farina , Alfonso Veropalumbo , Enzo Branchini , Massimo Guidi

Strongly lensed Active Galactic Nuclei (AGN) with an observable time delay can be used to constrain the expansion history of the Universe through time-delay cosmography (TDC). As the sample of time-delay lenses grows to statistical size,…