Clustering GCG: a viable option for unified dark matter-dark energy?

Abstract

We study the clustering Generalized Chaplygin Gas (GCG) as a possible candidate for dark matter-dark energy unification. The vanishing speed of sound ($c_s^2=0$) for the GCG fluid can be obtained by incorporating higher derivative operator in the original K-essence Lagrangian. The evolution of the density fluctuations in the GCG+Baryon fluid is studied in the linear regime. The observational constraints on the model are obtained using latest data from SNIa, $H(z)$, BAO and also for the $f{\sigma }_8$ measurements. The matter power spectra for the allowed parameter values are well behaved without any unphysical features.

Comments: 11 pages, Latex style, 6 eps figures