Gauge-invariant perturbations of relativistic non-perfect fluids in spherical spacetime

Fuente: arXiv
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Autori principali: Díaz-Guerra, David, Albertus, Conrado, Char, Prasanta, Pérez-García, M. Ángeles
Natura: Preprint
Pubblicazione: 2024
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author Díaz-Guerra, David
Albertus, Conrado
Char, Prasanta
Pérez-García, M. Ángeles
author_facet Díaz-Guerra, David
Albertus, Conrado
Char, Prasanta
Pérez-García, M. Ángeles
contents Astrophysical compact objects are usually studied using a perfect fluid model. However, in astrophysical processes out-of-equilibrium, dissipative effects become important to describe the dynamics of the system. In this work, we obtain gauge-invariant non-spherical perturbations of a self-gravitating non-perfect fluid in spherical spacetime. We use the Gerlach-Sengupta formalism to work with gauge-invariant metric perturbations, and the Gundlach-Martín-García approach to transform the equations of tensor perturbations into scalar equations. We calculate the dynamics of the dissipative contributions, e.g., viscosity and heat flux, using the Müller-Israel-Stewart equations in the gauge-invariant formalism. We obtain a set of field equations for the evolution of matter and metric perturbations in the polar and axial sectors. Specifically, in the former we find two wave equations sourced by the anisotropic contributions, and the evolution of all matter perturbations for radiative modes ($l\geq 2$). In the axial sector, we find one wave equation coupled to the evolution of matter perturbations. Finally, we comment on the contribution of dissipative effects in the lower-order multipoles ($l=0,1$) for both sectors.
format Preprint
id arxiv_https___arxiv_org_abs_2410_18081
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Gauge-invariant perturbations of relativistic non-perfect fluids in spherical spacetime
Díaz-Guerra, David
Albertus, Conrado
Char, Prasanta
Pérez-García, M. Ángeles
General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
Astrophysical compact objects are usually studied using a perfect fluid model. However, in astrophysical processes out-of-equilibrium, dissipative effects become important to describe the dynamics of the system. In this work, we obtain gauge-invariant non-spherical perturbations of a self-gravitating non-perfect fluid in spherical spacetime. We use the Gerlach-Sengupta formalism to work with gauge-invariant metric perturbations, and the Gundlach-Martín-García approach to transform the equations of tensor perturbations into scalar equations. We calculate the dynamics of the dissipative contributions, e.g., viscosity and heat flux, using the Müller-Israel-Stewart equations in the gauge-invariant formalism. We obtain a set of field equations for the evolution of matter and metric perturbations in the polar and axial sectors. Specifically, in the former we find two wave equations sourced by the anisotropic contributions, and the evolution of all matter perturbations for radiative modes ($l\geq 2$). In the axial sector, we find one wave equation coupled to the evolution of matter perturbations. Finally, we comment on the contribution of dissipative effects in the lower-order multipoles ($l=0,1$) for both sectors.
title Gauge-invariant perturbations of relativistic non-perfect fluids in spherical spacetime
topic General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2410.18081