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Please use this identifier to cite or link to this item: http://acervodigital.unesp.br/handle/11449/24396
Title: 
Physical approximations for the nonlinear evolution of perturbations in inhomogeneous dark energy scenarios
Author(s): 
Institution: 
  • Universidade de São Paulo (USP)
  • Universidade Estadual Paulista (UNESP)
ISSN: 
1550-7998
Abstract: 
The abundance and distribution of collapsed objects such as galaxy clusters will become an important tool to investigate the nature of dark energy and dark matter. Number counts of very massive objects are sensitive not only to the equation of state of dark energy, which parametrizes the smooth component of its pressure, but also to the sound speed of dark energy, which determines the amount of pressure in inhomogeneous and collapsed structures. Since the evolution of these structures must be followed well into the nonlinear regime, and a fully relativistic framework for this regime does not exist yet, we compare two approximate schemes: the widely used spherical collapse model and the pseudo-Newtonian approach. We show that both approximation schemes convey identical equations for the density contrast, when the pressure perturbation of dark energy is parametrized in terms of an effective sound speed. We also make a comparison of these approximate approaches to general relativity in the linearized regime, which lends some support to the approximations.
Issue Date: 
1-Jan-2009
Citation: 
Physical Review D. College Pk: Amer Physical Soc, v. 79, n. 2, p. 9, 2009.
Time Duration: 
9
Publisher: 
Amer Physical Soc
Source: 
http://dx.doi.org/10.1103/PhysRevD.79.023516
URI: 
http://hdl.handle.net/11449/24396
Access Rights: 
Acesso restrito
Type: 
outro
Source:
http://repositorio.unesp.br/handle/11449/24396
Appears in Collections:Artigos, TCCs, Teses e Dissertações da Unesp

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