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Related papers: A 3D radiative transfer framework: V. Homologous F…

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We present a general method to calculate radiative transfer including scattering in the continuum as well as in lines in spherically symmetric systems that are influenced by the effects of general relativity (GR). We utilize a comoving…

Astrophysics · Physics 2009-11-11 S. Knop , P. H. Hauschildt , E. Baron

We study the matching of a general spherically symmetric spacetime with a Vaidya-Reissner-Nordstrom solution. To that end, we study the properties of spherically symmetric electromagnetic fields and develop the proper gravitational and…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Francesc Fayos , Jose M. M. Senovilla , Ramon Torres

We propose an efficient numerical strategy for simulating fluid flow through porous media with highly oscillatory characteristics. Specifically, we consider non-linear diffusion models. This scheme is based on the classical homogenization…

Numerical Analysis · Mathematics 2020-02-04 Manuela Bastidas , Carina Bringedal , Sorin Pop , Florin Radu

In this paper we provide further spectral analysis of the general asymptotic scattering resonances formula of small high contrast 3D dielectrics of arbitrary shape, initially derived to a first order approximation. To investigate the…

Mathematical Physics · Physics 2022-04-22 Taoufik Meklachi , Kevin Li , Brian Adams

We describe the implementation and testing of a smoothed particle hydrodynamics (SPH) code that solves the equations of radiation hydrodynamics in the flux-limited diffusion (FLD) approximation. The SPH equations of radiation hydrodynamics…

Astrophysics · Physics 2009-11-10 Stuart C. Whitehouse , Matthew R. Bate

We consider the numerical approximation of boundary conditions in radiative transfer problems by a perfectly matched layer approach. The main idea is to extend the computational domain by an absorbing layer and to use an appropriate…

Numerical Analysis · Mathematics 2018-02-26 Herbert Egger , Matthias Schlottbom

This paper discusses some features of the spectral line profile theory used in the treatment of measured atomic transitions. It is shown that going beyond the established linear approximation for the spectral line contour in the case of its…

Atomic Physics · Physics 2024-05-03 D. Solovyev , A. Anikin , T. Zalialiutdinov

We present a novel method for diffusion-guided frameworks for view-consistent super-resolution (SR) in neural rendering. Our approach leverages existing 2D SR models in conjunction with advanced techniques such as Variational Score…

Computer Vision and Pattern Recognition · Computer Science 2025-01-07 Shrey Vishen , Jatin Sarabu , Saurav Kumar , Chinmay Bharathulwar , Rithwick Lakshmanan , Vishnu Srinivas

We will consider the resolution of the 3D non linear wave equation under the assumption of spherical symmetry on the Euclidian space. For this purpose, we will build a non trivial measure on distributions such that there exists a set of…

Analysis of PDEs · Mathematics 2012-05-22 Anne-Sophie de Suzzoni

Self similarity allows for analytic or semi-analytic solutions to many hydrodynamics problems. Most of these solutions are one dimensional. Using linear perturbation theory, expanded around such a one-dimensional solution, we find…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Re'em Sari , J. Nate Bode , Almog Yalinewich , Andrew MacFadyen

We present a numerical implementation of radiative transfer based on an explicitly photon-conserving advection scheme, where radiative fluxes over the cell interfaces of a structured or unstructured mesh are calculated with a second-order…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Margarita Petkova , Volker Springel

This paper investigates solutions of hyperbolic diffusion equations in $\mathbb{R}^3$ with random initial conditions. The solutions are given as spatial-temporal random fields. Their restrictions to the unit sphere $S^2$ are studied. All…

We compare the statistical properties of J=1-0 13CO spectra observed in the Perseus Molecular Cloud with synthetic J=1-0 13CO spectra from a 5 pc model cloud. The synthetic spectra are computed solving the non-LTE radiative transfer problem…

Astrophysics · Physics 2007-05-23 Paolo Padoan , John Bally , Youssef Billawala , Mika Juvela , AAke Nordlund

In this paper, we design and analyze a novel spectral method for the subdiffusion equation. As it has been known, the solutions of this equation are usually singular near the initial time. Consequently, direct application of the traditional…

Numerical Analysis · Mathematics 2022-04-06 Chuanju Xu , Wei Zeng

We propose a novel unsupervised learning approach to 3D shape correspondence that builds a multiscale matching pipeline into a deep neural network. This approach is based on smooth shells, the current state-of-the-art axiomatic…

Computer Vision and Pattern Recognition · Computer Science 2020-10-30 Marvin Eisenberger , Aysim Toker , Laura Leal-Taixé , Daniel Cremers

Using the 2D multi-group, flux-limited diffusion version of the code VULCAN/2D, that also incorporates rotation, we have calculated the collapse, bounce, shock formation, and early post-bounce evolutionary phases of a core-collapse…

Astrophysics · Physics 2009-11-10 R. Walder , A. Burrows , C. D. Ott , E. Livne , I. Lichtenstadt , M. Jarrah

We propose a new recursive method for simultaneous estimation of both the pose and the shape of a three-dimensional extended object. The key idea of the presented method is to represent the shape of the object using spherical harmonics,…

Robotics · Computer Science 2020-12-29 Gerhard Kurz , Florian Faion , Florian Pfaff , Antonio Zea , Uwe D. Hanebeck

Rigorous computer simulations of propagating electromagnetic fields have become an important tool for optical metrology and optics design of nanostructured components. As has been shown in previous benchmarks some of the presently used…

Imaging through opaque, highly scattering walls is a long sought after capability with potential applications in a variety of fields. The use of wavefront shaping to compensate for scattering has brought a renewed interest as a potential…

We developed a three-dimensional radiative transfer code for an ultra-relativistic background flow-field by using the Monte Carlo (MC) method in the context of gamma-ray burst (GRB) emission. For obtaining reliable simulation results in the…

High Energy Astrophysical Phenomena · Physics 2017-09-13 Ayako Ishii , Naofumi Ohnishi , Hiroki Nagakura , Hirotaka Ito , Shoichi Yamada