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Angle-resolved photoemission spectroscopy is a powerful experimental technique for studying anisotropic many-body interactions through the electron spectral function. Existing attempts to decompose the spectral function into non-interacting…

Materials Science · Physics 2026-05-01 Thomas P. van Waas , Christophe Berthod , Jan Berges , Nicola Marzari , J. Hugo Dil , Samuel Poncé

X-ray surveys of active galactic nuclei (AGNs) provide direct constraints on the properties of individual AGNs, such as their emission, obscuration, and accretion rate. Previous AGN population synthesis models have not addressed such…

High Energy Astrophysical Phenomena · Physics 2026-05-19 D. Gerolymatou , S. Paltani , C. Ricci , T. T. Ananna

A thermal active galactic nucleus (AGN) consist of a powerful, broad-band continuum source that is surrounded by several reprocessing media with different geometries and compositions. Here we investigate the expected spectropolarimetric…

High Energy Astrophysical Phenomena · Physics 2012-04-05 Frederic Marin , Rene W. Goosmann

The innermost regions of Active Galactic Nuclei (AGN) are critical for understanding galaxy evolution and the dynamics of matter near a Supermassive Black Hole (SMBH). Yet, due to smaller angular projections, it is very difficult to resolve…

Astrophysics of Galaxies · Physics 2024-02-07 Vivek Kumar Jha

This paper proposes a precise signal recovery method with multilayered non-convex regularization, enhancing sparsity/low-rankness for high-dimensional signals including images and videos. In optimization-based signal recovery, multilayered…

Signal Processing · Electrical Eng. & Systems 2024-09-24 Akari Katsuma , Seisuke Kyochi , Shunsuke Ono , Ivan Selesnick

Some response surface functions in complex engineering systems are usually highly nonlinear, unformed, and expensive-to-evaluate. To tackle this challenge, Bayesian optimization, which conducts sequential design via a posterior distribution…

Machine Learning · Statistics 2021-09-23 Areej AlBahar , Inyoung Kim , Xiaowei Yue

We present the results of a detailed study of the X-ray power spectra density (PSD) functions of twelve X-ray bright AGN, using almost all the archival XMM-Newton data. The total net exposure of the EPIC-pn light curves is larger than 350…

High Energy Astrophysical Phenomena · Physics 2016-06-15 D. Emmanoulopoulos , I. E. Papadakis , A. Epitropakis , T. Pecháček , M. Dovčiak , I. M. McHardy

Previous methods decompose blind super resolution (SR) problem into two sequential steps: \textit{i}) estimating blur kernel from given low-resolution (LR) image and \textit{ii}) restoring SR image based on estimated kernel. This two-step…

Computer Vision and Pattern Recognition · Computer Science 2020-11-26 Zhengxiong Luo , Yan Huang , Shang Li , Liang Wang , Tieniu Tan

This paper considers the non-linear inverse problem of reconstructing an electric conductivity distribution from the interior power density in a bounded domain. Applications include the novel tomographic method known as acousto-electric…

Optimization and Control · Mathematics 2018-08-29 B. J. Adesokan , Kim Knudsen , Venkateswaran P. Krishnan , Souvik Roy

X-ray reverberation is a powerful technique which maps out the structure of the inner regions of accretion disks around black holes using the echoes of the coronal emission reflected by the disk. While the theory of X-ray reverberation has…

High Energy Astrophysical Phenomena · Physics 2022-02-09 Lars Lund Thomsen , Jane Lixin Dai , Erin Kara , Chris Reynolds

We compute fully relativistic disc response functions in the case of the "lamp-post" geometry using the full observed reflection spectrum for various X-ray source heights, disc inclination, and spin values of the central black hole. Since…

High Energy Astrophysical Phenomena · Physics 2016-03-23 I. Papadakis , T. Pechacek , M. Dovciak , A. Epitropakis , D. Emmanoulopoulos , V. Karas

A novel and highly efficient computational framework for reconstructing binary-type images suitable for models of various complexity seen in diverse biomedical applications is developed and validated. Efficiency in computational speed and…

Optimization and Control · Mathematics 2024-02-09 Paul R. Arbic , Vladislav Bukshtynov

An efficient algorithm for adaptive kernel smoothing (AKS) of two-dimensional imaging data has been developed and implemented using the Interactive Data Language (IDL). The functional form of the kernel can be varied (top-hat, Gaussian…

Astrophysics · Physics 2009-11-11 H. Ebeling , D. A. White , F. V. N. Rangarajan

We present a new technique to generate the light curves of RRab stars in different photometric bands ($I$ and $V$ bands) using Artificial Neural Networks (ANN). A pre-computed grid of models was used to train the ANN, and the architecture…

Solar and Stellar Astrophysics · Physics 2023-04-03 Nitesh Kumar , Anupam Bhardwaj , Harinder P. Singh , Susmita Das , Marcella Marconi , Shashi M. Kanbur , Philippe Prugniel

The most popular method of the broad-line region size estimation in active galactic nuclei (AGN) is the reverberation mapping based on measuring the time delay between the continuum flux and the flux in the emission lines. In our work, we…

Instrumentation and Methods for Astrophysics · Physics 2020-01-29 Eugene Malygin , Roman Uklein , Elena Shablovinskaya , Aleksander Perepelitsyn , Aleksandra Grokhovskaya

We propose a new method of constraining the redshifts of individual extragalactic sources based on celestial coordinates and their ensemble statistics. Techniques from integer linear programming are utilized to optimize simultaneously for…

Instrumentation and Methods for Astrophysics · Physics 2016-11-15 Benjamin C. G. Lee , Tamás Budavári , Amitabh Basu , Mubdi Rahman

The obscuring circumnuclear torus of dusty molecular gas is one of the major components of active galactic nuclei (AGN). The torus can be studied by analyzing the time response of its infrared (IR) dust emission to variations in the AGN…

Astrophysics of Galaxies · Physics 2017-09-22 Triana Almeyda , Andrew Robinson , Michael Richmond , Billy Vazquez , Robert Nikutta

Imaging reconstruction of interferometric data is a hard ill-posed inverse problem. Its difficulty is increased when observing the Galactic Center, which is obscured by a scattering screen. This is because the scattering breaks the…

Instrumentation and Methods for Astrophysics · Physics 2025-06-25 Alejandro Mus , Teresa Toscano , Hendrik Müller , Guang-Yao Zhao , Andrei Lobanov , Ciriaco Goddi

This paper generalizes recent advances on quadratic manifold (QM) dimensionality reduction by developing kernel methods-based nonlinear-augmentation dimensionality reduction. QMs, and more generally feature map-based nonlinear corrections,…

Computational Engineering, Finance, and Science · Computer Science 2025-09-03 Alejandro N. Diaz , Jacob T. Needels , Irina K. Tezaur , Patrick J. Blonigan

Learned image compression methods have shown superior rate-distortion performance and remarkable potential compared to traditional compression methods. Most existing learned approaches use stacked convolution or window-based self-attention…

Image and Video Processing · Electrical Eng. & Systems 2024-01-03 Huairui Wang , Nianxiang Fu , Zhenzhong Chen , Shan Liu