Newtonian Approach to the Matter Power Spectrum of the Generalized Chaplygin Gas

TL;DR

This paper models the cosmic medium with a generalized Chaplygin gas and pressureless matter, using a neo-Newtonian approach to compute the matter power spectrum and compare it with observational data to evaluate dark sector models.

Contribution

It introduces a neo-Newtonian method to analyze the matter power spectrum of generalized Chaplygin gas models and assesses their viability against observational data.

Findings

Unified models are strongly disfavored by data.

Models with separate dark matter components fit the data well.

Observational data favor small and large values of the Chaplygin gas parameter α.

Abstract

We model the cosmic medium as the mixture of a generalized Chaplygin gas and a pressureless matter component. Within a neo-Newtonian approach we compute the matter power spectrum. The 2dFGRS data are used to discriminate between unified models of the dark sector and different models, for which there is separate dark matter, in addition to that accounted for by the generalized Chaplygin gas. Leaving the corresponding density parameters free, we find that the unified models are strongly disfavored. On the other hand, using unified model priors, the observational data are also well described, in particular for small and large values of the generalized Chaplygin gas parameter $\alpha$.