Eur. Phys. J. C (2017) 77: 479
https://doi.org/10.1140/epjc/s10052-017-5051-y

Regular Article - Theoretical Physics

Is the cosmological dark sector better modeled by a generalized Chaplygin gas or by a scalar field?

¹ Instituto de Física, Pontificia Universidad Católica de Valparaíso, Avenida Brasil 2950, Casilla 4059, Valparaiso, Chile
² Departamento de Física, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Campus de Goiabeiras, Vitória, Espírito Santo, CEP 29075-910, Brazil
³ National Research Nuclear University “MEPhI”, Kashirskoe sh. 31, Moscow, 115409, Russia

^* e-mail: winfried.zimdahl@pq.cnpq.br

Received: 13 March 2017
Accepted: 6 July 2017
Published online: 18 July 2017

Abstract

Both scalar fields and (generalized) Chaplygin gases have been widely used separately to characterize the dark sector of the universe. Here we investigate the cosmological background dynamics for a mixture of both these components and quantify the fractional abundances that are admitted by observational data from supernovae of type Ia and from the evolution of the Hubble rate. Moreover, we study how the growth rate of (baryonic) matter perturbations is affected by the dark-sector perturbations.