Ruling out the Modified Chaplygin Gas Cosmologies

TL;DR

This paper evaluates the Modified Chaplygin Gas model as a unified dark energy and dark matter candidate, concluding it is only viable when it reduces to the Generalized Chaplygin Gas, based on perturbative and observational analysis.

Contribution

It provides a perturbative and observational analysis that constrains the Modified Chaplygin Gas model, showing it is only consistent with data when B=0, thus reducing to the GCG model.

Findings

MCG model is not successful unless B=0

Perturbative analysis supports the conclusion

Observational data favor the GCG over MCG

Abstract

The Modified Chaplygin Gas (MCG) model belongs to the class of a unified models of dark energy (DE) and dark matter (DM). It is characterized by an equation of state (EoS) $p_c = B\rho - A/\rho^{\alpha}$, where the case $B=0$ corresponds to the Generalized Chaplygin Gas (GCG) model. Using a perturbative analysis and power spectrum observational data we show that the MCG model is not a sucessful candidate for the cosmic medium unless $B=0$. In this case, it reduces to the usual GCG model.