Modified gravity a la Galileon: Late time cosmic acceleration and observational constraints

Abstract

In this paper we examine the cosmological consequences of fourth order Galileon gravity. We carry out detailed investigations of the underlying dynamics and demonstrate the stability of one de Sitter phase. The stable de Sitter phase contains a Galileon field $\pi$ which is an increasing function of time (\dotπ>0). Using the required suppression of the fifth force, supernovae, BAO and CMB data, we constrain parameters of the model. We find that the $\pi$ matter coupling parameter $\beta$ is constrained to small numerical values such that $\beta$<0.02. We also show that the parameters of the third and fourth order in the action (c_3,c_4) are not independent and with reasonable assumptions, we obtain constraints on them. We investigate the growth history of the model and find that the sub-horizon approximation is not allowed for this model. We demonstrate strong scale dependence of linear perturbations in the fourth order Galileon gravity.

9 pages, 10 figures, references added, final version to appear in PRD

References in corpus (30)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Dynamics of dark energy
• Dark Energy and the Accelerating Universe
• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Disappearing cosmological constant in f(R) gravity
• Covariant Galileon
• Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
• Generalized Galileons: All scalar models whose curved background extensions maintain second-order field equations and stress tensors
• Imperfect Dark Energy from Kinetic Gravity Braiding
• Future of the universe in modified gravitational theories: Approaching to the finite-time future singularity
• Approaches to Understanding Cosmic Acceleration
• Large Scale Structure as a Probe of Gravitational Slip
• Galileon Cosmology
• The future evolution and finite-time singularities in $F(R)$-gravity unifying the inflation and cosmic acceleration
• DBI and the Galileon reunited
• A Singularity Problem with f(R) Dark Energy
• The Dynamics of Quintessence, The Quintessence of Dynamics
• Relativistic stars in f(R) gravity, and absence thereof
• On the Growth of Perturbations as a Test of Dark Energy
• On the growth of linear perturbations
• Non-linear Evolution of Matter Power Spectrum in Modified Theory of Gravity
• The dispersion of growth of matter perturbations in f(R) gravity
• Density perturbations in general modified gravitational theories
• Aspects of cosmological expansion in F(R) gravity models
• The existence of relativistic stars in f(R) gravity
• Growth factor parametrization and modified gravity
• Can higher curvature corrections cure the singularity problem in f(R) gravity?
• The growth of matter perturbations in some scalar-tensor DE models
• Roles of dark energy perturbations in the dynamical dark energy models: Can we ignore them?
• Lectures on Dark Energy and Cosmic Acceleration

Cited by in corpus (8)

• Galileon inflation
• Higgs G-inflation
• Observational constraints on Galileon cosmology
• Matter perturbations in Galileon cosmology
• Primordial non-Gaussianities in general modified gravitational models of inflation
• Primordial non-Gaussianity from G-inflation
• Cosmology of the selfaccelerating third order Galileon
• Galileon accretion