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- Spherical collapse in chameleon models
- Universidade Estadual Paulista (UNESP)
- Univ Paris 07
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
- Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
- Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
- EU Marie Curie Research & Training network "UniverseNet"
- Agence Nationale de la Recherche
- EU Marie Curie Research & Training network "UniverseNet": MRTN-CT-2006-035863
- Agence Nationale de la Recherche: ANR-09-BLAN-0157
- We study the gravitational collapse of an overdensity of nonrelativistic matter under the action of gravity and a chameleon scalar field. We show that the spherical collapse model is modified by the presence of a chameleon field. In particular, we find that even though the chameleon effects can be potentially large at small scales, for a large enough initial size of the inhomogeneity the collapsing region possesses a thin shell that shields the modification of gravity induced by the chameleon field, recovering the standard gravity results. We analyse the behaviour of a collapsing shell in a cosmological setting in the presence of a thin shell and find that, in contrast to the usual case, the critical density for collapse in principle depends on the initial comoving size of the inhomogeneity.
- Journal of Cosmology and Astroparticle Physics. Bristol: Iop Publishing Ltd, n. 8, p. 26, 2010.
- Iop Publishing Ltd
- modified gravity
- dark energy theory
- Acesso restrito
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