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Centro de Astrofísica da Universidade do Porto

The ΛCDM limit of the generalized Chaplygin gas scenario

P. P. Avelino, L. M. G. Beça, J. P. M. de Carvalho, C. J. A. P. Martins

Abstract
We explicitly demonstrate that, contrary to recent claims, the dynamics of a generalized Chaplygin gas model with an equation of state p = -C (where C is a positive constant) is equivalent to that of a standard LambdaCDM model to first order in the metric perturbations. We further argue that the analogy between the two models goes well beyond linear theory and conclude that they cannot be distinguished based on gravity alone.

Keywords
dark matter, dark energy theory, cosmological perturbation theory

Journal of Cosmology and Astroparticle Physics
Volume 9, Page 002_1
September 2003

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