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 0c_s² = ) 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 fσ₈ measurements. The matter power spectra for the allowed parameter values are well behaved without any unphysical features.