Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Local conditions separating expansion from collapse in spherically symmetric models with anisotropic pressures

Full text
Author(s):
Mimoso, Jose P. [1, 2] ; Le Delliou, Morgan [3, 1] ; Mena, Filipe C. [4]
Total Authors: 3
Affiliation:
[1] Univ Lisbon, Fac Ciencias, Ctr Astron & Astrofis, P-1769016 Lisbon - Portugal
[2] Univ Lisbon, Fac Ciencias, Dept Fis, P-1769016 Lisbon - Portugal
[3] Univ Sao Paulo, Inst Fis, Dept Fis Matemat, BR-05314970 Sao Paulo - Brazil
[4] Univ Minho, Ctr Matemat, P-4710057 Braga - Portugal
Total Affiliations: 4
Document type: Journal article
Source: Physical Review D; v. 88, n. 4 AUG 1 2013.
Web of Science Citations: 31
Abstract

We investigate spherically symmetric spacetimes with an anisotropic fluid and discuss the existence and stability of a separating shell dividing expanding and collapsing regions. We resort to a 3 + 1 splitting and obtain gauge invariant conditions relating intrinsic spacetime quantities to properties of the matter source. We find that the separating shell is defined by a generalization of the Tolman-Oppenheimer-Volkoff equilibrium condition. The latter establishes a balance between the pressure gradients, both isotropic and anisotropic, and the strength of the fields induced by the Misner-Sharp mass inside the separating shell and by the pressure fluxes. This defines a local equilibrium condition, but conveys also a nonlocal character given the definition of the Misner-Sharp mass. By the same token, it is also a generalized thermodynamical equation of state as usually interpreted for the perfect fluid case, which now has the novel feature of involving both the isotropic and the anisotropic stresses. We have cast the governing equations in terms of local, gauge invariant quantities that are revealing of the role played by the anisotropic pressures and inhomogeneous electric part of the Weyl tensor. We analyze a particular solution with dust and radiation that provides an illustration of our conditions. In addition, our gauge invariant formalism not only encompasses the cracking process from Herrera and co-workers but also reveals transparently the interplay and importance of the shear and of the anisotropic stresses. (AU)

FAPESP's process: 11/24089-5 - Astroparticles: cosmology and structures formation - galaxies - clusters
Grantee:Elcio Abdalla
Support Opportunities: Research Grants - Visiting Researcher Grant - International