Linear perturbations in Galileon gravity models
arXiv:1208.0600 · doi:10.1103/PhysRevD.86.124016
Abstract
We study the cosmology of Galileon modified gravity models in the linear perturbation regime. We derive the fully covariant and gauge invariant perturbed field equations using two different methods, which give consistent results, and solve them using a modified version of the {\tt CAMB} code. We find that, in addition to modifying the background expansion history and therefore shifting the positions of the acoustic peaks in the cosmic microwave background (CMB) power spectrum, the Galileon field can cluster strongly from early times, and causes the Weyl gravitational potential to grow, rather than decay, at late times. This leaves clear signatures in the low- CMB power spectrum through the modified integrated Sachs-Wolfe effect, strongly enhances the linear growth of matter density perturbations and makes distinctive predictions for other cosmological signals such as weak lensing and the power spectrum of density fluctuations. The quasi-static approximation is shown to work quite well from small to the near-horizon scales. We demonstrate that Galileon models display a rich phenomenology due to the large parameter space and the sensitive dependence of the model predictions on the Galileon parameters. Our results show that some Galileon models are already ruled out by present data and that future higher significance galaxy clustering, ISW and lensing measurements will place strong constraints on Galileon gravity.
version 2. Minor changes to figures and text, and typo corrected in Eq. (A7). References added. Published in PRD
References in corpus (19)
- Dynamics of dark energy
- Spectra and Light Curves of Six Type Ia Supernovae at 0.511 < z < 1.12 and the Union2 Compilation
- Covariant Galileon
- Generalized Galileons: All scalar models whose curved background extensions maintain second-order field equations and stress tensors
- Imperfect Dark Energy from Kinetic Gravity Braiding
- Avoiding Dark Energy with 1/R Modifications of Gravity
- f(R) Gravity and Chameleon Theories
- Galileon Cosmology
- Searching for modified growth patterns with tomographic surveys
- Multi-field galileons and higher co-dimension branes
- The detectability of baryonic acoustic oscillations in future galaxy surveys
- Observational constraints on Galileon cosmology
- Matter perturbations in Galileon cosmology
- The 2dF-SDSS LRG and QSO survey: evolution of the clustering of luminous red galaxies since z = 0.6
- Modified gravity a la Galileon: Late time cosmic acceleration and observational constraints
- Modelling redshift space distortions in hierarchical cosmologies
- The Three-Point Correlation Function of Luminous Red Galaxies in the Sloan Digital Sky Survey
- The linear growth rate of structure in Parametrized Post Friedmannian Universes
- Fab 5: Noncanonical Kinetic Gravity, Self Tuning, and Cosmic Acceleration