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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

Two methods are developed for solving the steady-state spherically symmetric radiative transfer equation for resonance line radiation emitted by a point source in the Intergalactic Medium. One method is based on solving the ray and moment…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Jonathan Higgins , Avery Meiksin

We present a comprehensive analytical study of radiative transfer using the method of moments and include the effects of non-isotropic scattering in the coherent limit. Within this unified formalism, we derive the governing equations and…

Earth and Planetary Astrophysics · Physics 2015-06-19 Kevin Heng , João M. Mendonça , Jae-Min Lee

This article considers the computational (acoustic) wave propagation in strongly heterogeneous structures beyond the assumption of periodicity. A high contrast between the constituents of microstructured multiphase materials can lead to…

Numerical Analysis · Mathematics 2020-01-29 Daniel Peterseim , Barbara Verfürth

A finite element method for solving the resonance line transfer problem in moving media is presented. The algorithm works in three spatial dimensions on unstructured grids which are adaptively refined by means of an a posteriori error…

Astrophysics · Physics 2009-11-07 E. Meinkoehn , S. Richling

In this paper, we propose and analyze a new semi-implicit stochastic multiscale method for the radiative heat transfer problem with additive noise fluctuation in composite materials. In the proposed method, the strong nonlinearity term…

Numerical Analysis · Mathematics 2026-05-12 Shan Zhang , Yajun Wang , Xiaofei Guan

Measured values of the brightness temperature of low-frequency synchrotron radiation emitted by powerful extragalactic sources reach 10^11--10^12 K. If some amount of nonrelativistic ionized gas is present within such sources, it should be…

Astrophysics · Physics 2009-11-06 Sergei Sazonov , Rashid Sunyaev

We present a general relativistic, ray-tracing radiative transfer code RAIKOU for multi-wavlength studies of spectra and images including the black hole shadows around Kerr black holes. Important radiative processes in hot plasmas around…

High Energy Astrophysical Phenomena · Physics 2023-06-28 Tomohisa Kawashima , Ken Ohsuga , Hiroyuki R. Takahashi

We present detailed computations of the vertical structure of an accretion disc illuminated by hard X-ray radiation with the code {\sc titan-noar} suitable for Compton thick media. The energy generated via accretion is dissipated partially…

Astrophysics · Physics 2009-11-07 A. Różańska , A. -M. Dumont , B. Czerny , S. Collin

Studies of solar and stellar convection often employ simple polytropic setups using the diffusion approximation instead of solving the proper radiative transfer equation. This allows one to control separately the polytropic index of the…

Solar and Stellar Astrophysics · Physics 2014-11-14 Atefeh Barekat , Axel Brandenburg

A method for the fast and accurate solution of the radiative transfer equation in plane-parallel media with coherent isotropic scattering is presented. This largely analytical approach uses the formalism of meromorphic functions in order to…

Astrophysics · Physics 2007-05-23 G. V. Efimov , N. V. Kryzhevoi , W. von Waldenfels , R. Wehrse

Context: Remote light scattering and thermal infrared observations provide clues about the physical properties of cometary and interplanetary dust particles. Identifying these properties will lead to a better understanding of the formation…

Earth and Planetary Astrophysics · Physics 2020-02-05 Johannes Markkanen , Jessica Agarwal

We deduce the equations that describe how polarized radiation is Comptonized by a hot electron gas. Low frequencies are considered, and the equations are expanded to second order in electron velocities. Induced scattering terms are included…

Astrophysics · Physics 2009-10-31 Frode K. Hansen , Per B. Lilje

We present a new radiative transfer code for axi-symmetric stellar atmospheres and compare test results against 1D and 2D models with and without velocity fields. The code uses the short characteristic method with modifications to handle…

Astrophysics · Physics 2009-11-11 J. Zsargo , D. J. Hillier , L. N. Georgiev

The massive hot stars play crucial role in the dynamics of galaxies. These stars influence their surroundings through strong winds which are highly structured processes. The theoretical study of the non-symmetric phenomena of the stellar…

Solar and Stellar Astrophysics · Physics 2026-01-30 Jakub Fišák , Jiří Kubát , Nicolas Moens , Brankica Kubátová

Context: State of the art quantitative spectroscopy of OB-stars compares synthetic spectra (calculated by means of 1D, spherically symmetric computer codes) with observations. Certain stellar atmospheres, however, show strong deviations…

Solar and Stellar Astrophysics · Physics 2018-09-12 L. Hennicker , J. Puls , N. D. Kee , J. O. Sundqvist

Ongoing MeV telescopes such as INTEGRAL/SPI and Fermi/GBM, and proposed telescopes including the recently accepted COSI and the e-ASTROGAM and AMEGO missions, provide another window in understanding transients. Their signals contain…

High Energy Astrophysical Phenomena · Physics 2023-03-13 Shing-Chi Leung

A new Monte-Carlo algorithm for calculating time-dependent radiative-transfer under the assumption of LTE is presented. Unlike flux-limited diffusion the method is polychromatic, includes scattering, and is able to treat the optically thick…

Solar and Stellar Astrophysics · Physics 2015-05-28 Tim J. Harries

Muon ionization cooling involves passing particles through solid or liquid absorbers. Careful simulations are required to design muon cooling channels. New features have been developed for inclusion in the transfer map code COSY Infinity to…

Accelerator Physics · Physics 2018-08-15 Josiah Kunz , Pavel Snopok , Martin Berz , Kyoko Makino

A three-dimensional Monte Carlo code for modelling radiation transport in Type Ia supernovae is described. In addition to tracking Monte Carlo quanta to follow the emission, scattering and deposition of radiative energy, a scheme involving…

Astrophysics · Physics 2008-11-26 S. A. Sim