The extreme limit of the generalised Chaplygin gas

Journal Article · Mon Mar 01 04:00:00 EST 2010 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2010/03/012· OSTI ID:22273011

Unified Dark Matter models describe Dark Matter and Dark Energy as a single entity which is, in the simplest case, embodied in a perfect barotropic fluid. It is a well-established fact that small adiabatic perturbations of Unified Dark Matter have an evolution characterised by oscillations and decay which provide predictions on the Cosmic Background Radiation anisotropies which are in poor agreement with observation. In this paper we investigate the generalised Chaplygin gas and we find that the Integrated Sachs-Wolfe effect excludes the model for 10{sup −3} < α < 350. We discuss the implications on the background evolution of the Universe if large values of α are considered. In this case, the Universe expansion mimics a matter-dominated phase abruptly followed by a de Sitter one at the transition redshift z{sub tr}. Thanks to an analysis of the type Ia supernovae Constitution set we are able to place z{sub tr} = 0.22.

• OSTI ID: 22273011
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 03 Vol. 2010; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
BACKGROUND RADIATION
COSMOLOGY
DE SITTER GROUP
DE SITTER SPACE
DISTURBANCES
INFLATIONARY UNIVERSE
NONLUMINOUS MATTER
OSCILLATIONS
RED SHIFT
SUPERNOVAE
UNIVERSE