Extension of the LambdaCDM model, based on the scalar-tensor theory of gravitation.

Name: William Celestino Algoner Jorge
Type: PhD thesis
Publication date: 05/10/2017
Advisor:

Namesort descending Role
Winfried Ernst Wilhelm Zimdahl Advisor *

Examining board:

Namesort descending Role
Davi Cabral Rodrigues Internal Examiner *
Hermano Endlich Schneider Velten External Examiner *
Ilia Chapiro External Examiner *
Oliver Fabio Piattella Internal Examiner *
Sergio Eduardo de Carvalho Eyer Jorás External Examiner *
Winfried Ernst Wilhelm Zimdahl Advisor *

Summary: Cosmological measurements of both the expansion history H(z) and growth history fσ8 have matured, and the two together provide an important test of cosmological scalar-tensor theory, in particular the Brans-Dicke type which provides an extension to the ΛCDM model. We construct an explicitanalytic expression (through an ansatz) as a modification of the Hubble rate of the ΛCDM model,in which it is given in terms of a constant parameter m, which quantifies the differences between the background dynamics of the scalar-tensor theories and general relativity, thus performing a statistical analysis SNIa, H(z) and BAO to find the minimum fitting of the constant parameter. To complete our system, we introduce equations of fluid dynamical perturbations, the extension of the ΛCDM in what regards develops an effective fluid approach for the matter growth function. We quantify the impact
of deviations from standard background, of anisotropic stress and of non-vanishing perturbations of effective dark energy component on the matter growth rate function fσ8 and confront the results with
redshift-space distortion (RSD) measurements.

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