Wilhelm, Zimdahl Winfried ErnstVelten, Hermano Endlich SchneiderAlgoner Jorge, William Celestino2023-02-082023-02-082019WILHELM, Z. W. E.; VELTEN, H. E. S.; ALGONER JORGE, W. C. Matter growth in extended ΛCDM cosmology. International Journal of Modern Physics D, v. 28, n. 6, artigo 1950086, 2019. Disponível em: <https://www.worldscientific.com/doi/abs/10.1142/S021827181950086X>. Acesso em: 06 jul. 2022.1793-6594http://www.repositorio.ufop.br/jspui/handle/123456789/16143On the basis of a previously established scalar–tensor extension of the ΛCDM model, we develop an effective fluid approach for the matter growth function. This extended ΛCDM (henceforth eΦΛCDM) cosmology takes into account deviations from the Standard Model both via a modified background expansion and by the inclusion of geometric anisotropic stresses as well as of perturbations of the geometric dark-energy equivalent. The background dynamics is governed by an explicit analytic expression for the Hubble rate in which modifications of the Standard Model are given in terms of a single constant parameter [W. C. Algoner, H. E. S. Velten and W. Zimdahl, J. Cosmol. Astropart. Phys. 1611 (2016) 034]. To close the system of fluid-dynamical perturbation equations, we introduce two phenomenological parameters through which the anisotropic stress is related both to the total energy density perturbation of the cosmic substratum and to relative perturbations in the effective two-component system. We quantify the impact of deviations from the standard background, of anisotropic stresses and of nonvanishing perturbations of the effective dark-energy component on the matter growth rate function fσ8 and confront the results with recent redshift-space distortion (RSD) measurements.en-USrestritoFluid cosmologyCosmological perturbationsScalar–tensor theoryAnisotropic stressMatter growth rateArtigo publicado em periodicohttps://www.worldscientific.com/doi/abs/10.1142/S021827181950086Xhttps://doi.org/10.1142/S021827181950086X