Fingerprinting Dark Energy III: distinctive marks of viscosity

Details Fingerprinting Dark Energy III: distinctive marks of viscosity Fingerprinting Dark Energy III: distinctive marks of viscosity

2012-03-09

arxiv.org/abs/1203.2157v1

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

14 pages, 8 figures, to be submitted to PRD

Scientific paper

The characterisation of dark energy is one of the primary goals in cosmology especially now that many new experiments are being planned with the aim of reaching a high sensitivity on cosmological parameters. It is known that if we move away from the simple cosmological constant model then we need to consider perturbations in the dark energy fluid. This means that dark energy has two extra degrees of freedom: the sound speed $\cs$ and the anisotropic stress $\sigma$. If dark energy is inhomogenous at the scales of interest then the gravitational potentials are modified and the evolution of the dark matter perturbations is also directly affected. In this paper we add an anisotropic component to the dark energy perturbations. Following the idea introduced in \cite{Sapone:2009mb}, we solve analytically the equations of perturbations in the dark sector, finding simple and accurate approximated solutions. We also find that the evolution of the density perturbations is governed by an effective sound speed which depends on both the sound speed and the anisotropic stress parameter. We then use these solutions to look at the impact of the dark energy perturbations on the matter power spectrum and on the Integrated Sachs-Wolfe effect in the Cosmic Microwave Background.

Affiliated with

Also associated with

No associations

Rating

Fingerprinting Dark Energy III: distinctive marks of viscosity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Fingerprinting Dark Energy III: distinctive marks of viscosity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fingerprinting Dark Energy III: distinctive marks of viscosity will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-302934