Matter growth in imperfect fluid cosmology.

• Autor(a) principal: Wilhelm, Zimdahl Winfried Ernst
• Data de Publicação: 2019
• Outros Autores: Velten, Hermano Endlich Schneider, Algoner Jorge, William Celestino
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFOP
• Texto Completo: http://www.repositorio.ufop.br/jspui/handle/123456789/16005; https://doi.org/10.3390/universe5030068
• topic: Fluid cosmology; Cosmological perturbation theory; Scalar-tensor theory; Cosmic structure formation

Extensions of Einstein’s General Relativity (GR) can formally be given a GR structure in which additional geometric degrees of freedom are mapped on an effective energy-momentum tensor. The corresponding effective cosmic medium can then be modeled as an imperfect fluid within GR. The imperfect fluid structure allows us to include, on a phenomenological basis, anisotropic stresses and energy fluxes which are considered as potential signatures for deviations from the cosmological standard Λ-cold-dark-matter (ΛCDM) model. As an example, we consider the dynamics of a scalar-tensor extension of the standard model, the eΦΛCDM model. We constrain the magnitudes of anisotropic pressure and energy flux with the help of redshift-space distortion (RSD) data for the matter growth function f σ8.