An algorithm to generate anisotropic rotating fluids with vanishing viscosity

Viaggiu, Stefano

doi:10.1140/epjp/i2018-12345-x

Cited by 3 publications

(2 citation statements)

References 43 publications

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“…From (27) we deduce that H < 0, but for the physical request m ,r > 0 we must have H > 0. Consequently in the case C ̸ = 0 SEC is violated at least in a neighborhood of R. For C = 0, from (25) we have H < 0 and WEC is violated. Moreover, from (25) for C < 0 and R > 3m and H > 0, condition E + P ϕ can be certainly satisfied with |C| ⩾ RH/(R − 3m).…”

Section: Static and Slowly Rotating Limitmentioning

confidence: 90%

“…Consequently in the case C ̸ = 0 SEC is violated at least in a neighborhood of R. For C = 0, from (25) we have H < 0 and WEC is violated. Moreover, from (25) for C < 0 and R > 3m and H > 0, condition E + P ϕ can be certainly satisfied with |C| ⩾ RH/(R − 3m). For H = 0 and C < 0 from (27) we have a violation of SEC.…”

Section: Static and Slowly Rotating Limitmentioning

confidence: 90%

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Physically viable rotating mass solutions surrounding Kerr black holes

Viaggiu

2023

Class. Quantum Grav.

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There exists in literature an increasing interest in the study of mass distributions surrounding black holes as describing dark matter halo in spiral galaxies. Motivated by this interest, we study a very recent new class of rotating solutions that are suitable to build anisotropic matter sources surrounding rotating black holes. Contrary to the mainstream approach, instead of use the so called regular black holes as central objects, we perform a smooth matching between the aforementioned anisotropic matter and a central vacuum Kerr black hole. In this framework, we study in full generality energy conditions near the matching surface. As a result, we found that, after imposing the vanishing of the energy density$E$ at the matching surface, if weak and dominant energy conditions (WEC,DEC) are satisfied, then unavoidable strong energy conditions is violated, i.e. near the event horizon only matter with dark energy-like features is allowed. As an application, we present two solutions everywhere satisfying DEC. The first one is asymptotically flat and equipped with a non vanishing electric charge, while the second solution presented is equipped with a non-vanishing energy flow around the symmetry axis and it is not asymptotically flat.

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Section: Static and Slowly Rotating Limitmentioning

confidence: 90%

Section: Static and Slowly Rotating Limitmentioning

confidence: 90%

Physically viable rotating mass solutions surrounding Kerr black holes

Viaggiu

2023

Class. Quantum Grav.

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A new class of anisotropic rotating fluids and some throat-like sources for Kerr metric as examples

Viaggiu

2023

Int. J. Mod. Phys. D

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Motivated by the increasing interest in finding physically viable rotating sources, we present a new class of anisotropic rotating solutions. The energy–momentum tensor compatible with the metric is composed of anisotropic matter with a nonvanishing energy flow around the symmetry axis and vanishing viscosity. The new class of solutions can be used to find new possible sources for the Kerr metric, to obtain new regular black hole solutions and to study galaxies with a central rotating black hole and an halo of dark matter. As an example, we obtain a five-parameter class of solutions representing a two-way traversable wormhole smoothly matched to the Kerr one and satisfying all energy conditions outside the wormhole for a wide range of parameters, in particular for compact objects. Finally, with a simple modification of the aforementioned solution, we obtain a source for Kerr metric with a throat geometry, nonrepresenting a two-way traversable wormhole and satisfying all energy conditions.

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Rotating regular black holes and other compact objects with a Tolman-type potential as a regular interior for the Kerr metric

Masa,

Zanchin

2024

Int. J. Mod. Phys. D

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In this paper, we obtain a new class of stationary axisymmetric spacetimes by using the Gürses–Gürsey metric with an appropriate mass function in order to generate a rotating core of matter that may be smoothly matched to the exterior Kerr metric. The same stationary spacetimes may be obtained by applying a slightly modified version of the Newman–Janis algorithm to a nonrotating spherically symmetric seed metric. The starting spherically symmetric configuration represents a nonisotropic de Sitter-type fluid whose radial pressure [Formula: see text] satisfies an state equation of the form [Formula: see text], where the energy density [Formula: see text] is chosen to be the Tolman-type-VII energy density [R. C. Tolman, Phys. Rev. 55, 364 (1939)]. The resulting rotating metric is then smoothly matched to the exterior Kerr metric, and the main properties of the obtained geometries are investigated. All the solutions considered in this study are regular in the sense they are free of curvature singularities. Depending on the relative values of the total mass m and rotation parameter a, the resulting stationary spacetimes represent different kinds of rotating compact objects such as regular black holes, extremal regular black holes, and regular starlike configurations.

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An algorithm to generate anisotropic rotating fluids with vanishing viscosity

Abstract: Starting with generic stationary axially symmetric spacetimes depending on two spacelike isotropic orthogonal coordinates x 1

Cited by 3 publications

References 43 publications

Physically viable rotating mass solutions surrounding Kerr black holes

Physically viable rotating mass solutions surrounding Kerr black holes

A new class of anisotropic rotating fluids and some throat-like sources for Kerr metric as examples

Rotating regular black holes and other compact objects with a Tolman-type potential as a regular interior for the Kerr metric

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