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arXiv · 1702.00651

Does a generalized Chaplygin gas correctly describe the cosmological dark sector?

R. F. vom Marttens·L. Casarini·W. Zimdahl·W. S. Hipólito-Ricaldi·D. F. Mota
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Abstract

Yes, but only for a parameter value that makes it almost coincide with the standard model. We reconsider the cosmological dynamics of a generalized Chaplygin gas (gCg) which is split into a cold dark matter (CDM) part and a dark energy (DE) component with constant equation of state. This model, which implies a specific interaction between CDM and DE, has a $Λ$CDM limit and provides the basis for studying deviations from the latter. Including matter and radiation, we use the (modified) CLASS code \cite{class} to construct the CMB and matter power spectra in order to search for a gCg-based concordance model that is in agreement with the SNIa data from the JLA sample and with recent Planck data. The results reveal that the gCg parameter $α$ is restricted to $|α|\lesssim 0.05$, i.e., to values very close to the $Λ$CDM limit $α=0$. This excludes, in particular, models in which DE decays linearly with the Hubble rate.

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R. F. vom Marttens, L. Casarini, W. Zimdahl, W. S. Hipólito-Ricaldi, D. F. Mota. 2017-02-02. Does a generalized Chaplygin gas correctly describe the cosmological dark sector?. https://arxiv.org/abs/1702.00651

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