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We model a radiating star undergoing dissipative gravitational collapse in the form of radial heat flux. The exterior of the collapsing star is described by the generalised Vaidya solution representing a mixture of null radiation and…

General Relativity and Quantum Cosmology · Physics 2017-09-13 NF Naidu , M Govender , S Thirukkanesh , SD Maharaj

We present an analysis of the general relativistic Boltzmann equation for radiation, appropriate to the case where particles and photons interact through Thomson scattering, and derive the radiation energy-momentum tensor in the diffusion…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Eric R. Coughlin , Mitchell C. Begelman

Photon trapping is believed to be an important mechanism in super-Eddington accretion, which greatly reduces the radiative efficiency as photons are swallowed by the central black hole before they can escape from the accretion flow. This…

High Energy Astrophysical Phenomena · Physics 2023-08-17 Cheng-Liang Jiao

We analyse the gravitational behaviour of a relativistic heat conducting fluid in a shear-free spherically symmetric spacetime. We show that the isotropy of pressure is a consistency condition which realises a second order nonlinear…

General Relativity and Quantum Cosmology · Physics 2015-12-31 B. P. Brassel , S. D. Maharaj , G. Govender

We perform simulations in a simple model that aims to mimic the hydrodynamic evolution of a relativistic fluid during a cosmological first-order phase transitions. The observable we are concerned with is hereby the spectrum of gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-21 Thomas Konstandin

This article focuses on the formulation of some scalar factors which are uniquely expressed in terms of matter variables for dynamical charged dissipative cylindrical geometry in a standard gravity model $\mathcal{R}+\Phi\mathcal{Q}$…

General Relativity and Quantum Cosmology · Physics 2022-09-05 M. Sharif , Tayyab Naseer

We study magnetically powered relativistic outflows in which a part of the magnetic energy is dissipated internally by reconnection. For GRB parameters, and assuming that the reconnection speed scales with the Alfven speed, significant…

Astrophysics · Physics 2009-11-07 Georg Drenkhahn

We study the implications of quantum fluctuations of a dispersive medium, under steady rotation, either in or out of thermal equilibrium with its environment. A rotating object exhibits a quantum instability by dissipating its mechanical…

Quantum Physics · Physics 2014-07-23 Mohammad F. Maghrebi , Robert L. Jaffe , Mehran Kardar

The Misner and Sharp approach to the study of gravitational collapse is extended to the dissipative case in, both, the streaming out and the diffusion approximations. The role of different terms in the dynamical equation are analyzed in…

General Relativity and Quantum Cosmology · Physics 2008-11-26 L. Herrera , N. O. Santos

A module for the ZEUS-2D code is described which may be used to solve the equations of radiation hydrodynamics to order unity in v/c, in the flux-limited diffusion (FLD) approximation. In this approximation, the tensor Eddington factor f…

Astrophysics · Physics 2009-11-06 N. J. Turner , J. M. Stone

We extend a previous analysis concerning cosmological fluids with generalized equations of state in order to study inflationary scenarios. In the framework of the slow-roll approximation we find the expressions for the perturbation…

Astrophysics · Physics 2009-10-28 G. Mangano , G. Miele , C. Stornaiolo

I study the formation of Comptonization spectra in spherically symmetric, fast moving media in a flat spacetime. I analyze the mathematical character of the moments of the transfer equation in the system-frame and describe a numerical…

Astrophysics · Physics 2009-10-31 Dimitrios Psaltis

Understanding radiative transfer in random media like micro/nanoporous and particulate materials, allows people to manipulate the scattering and absorption of radiation, as well as opens new possibilities in applications such as imaging…

Mesoscale and Nanoscale Physics · Physics 2018-02-28 B. X. Wang , C. Y. Zhao

In the rapidly rotating limit, we derive a balanced set of reduced equations governing the strongly nonlinear development of the convective wall-mode instability in the interior of a general container. The model illustrates that wall-mode…

The general relativistic Poynting-Robertson (PR) effect is a very important dissipative phenomenon occurring in high-energy astrophysics. Recently, it has been proposed a new model, which upgrades the two-dimensional (2D) description in the…

General Relativity and Quantum Cosmology · Physics 2023-03-28 Vittorio De Falco

Time-dependent meridional circulation and differential rotation in radiative zones are central open issues in stellar evolution theory. We streamline this challenging problem using the downward control principle of atmospheric science,…

Solar and Stellar Astrophysics · Physics 2025-02-18 Deepayan Banik , Kristen Menou

This paper presents a new code for performing multidimensional radiation hydrodynamic (RHD) simulations on parallel computers involving anisotropic radiation fields and nonequilibrium effects. The radiation evolution modules described here…

Astrophysics · Physics 2009-11-07 John C. Hayes , Michael L. Norman

Using the logarithmic superfluid model of physical vacuum, one can formulate a quantum theory, which successfully recovers Einstein's theory of relativity in low-momenta limit, but otherwise has different foundations and predictions. We…

High Energy Physics - Theory · Physics 2020-11-25 Konstantin G. Zloshchastiev

We define and study on Lorentz manifolds a family of covariant diffusions in which the quadratic variation is locally determined by the curvature. This allows the interpretation of the diffusion effect on a particle by its interaction with…

Probability · Mathematics 2015-05-18 Jacques Franchi , Yves Le Jan

A simple exact covariant model in which a scalar particle is modeled as a bound state of two different particles is used to elucidate relativistic aspects of electromagnetic form factors. The model form factor is computed using an exact…

Nuclear Theory · Physics 2009-10-29 Gerald A. Miller