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

TL;DR

This paper investigates the clustering Generalized Chaplygin Gas as a unified dark matter-dark energy model, demonstrating its viability through theoretical modifications and observational data constraints, with well-behaved power spectra.

Contribution

It introduces a higher derivative operator to achieve zero sound speed in GCG, enabling it to serve as a unifying dark matter-dark energy candidate, supported by observational data analysis.

Findings

GCG with zero sound speed fits observational data well.

Matter power spectra are free of unphysical features.

Model remains consistent with latest cosmological measurements.

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.