CERN Accelerating science

Preprint
Report number	arXiv:1005.0295 ; IFT-UAM-CSIC-10-28 ; FTUAM-10-07
Title	Dark Coupling and Gauge Invariance
Author(s)	Gavela, M B ; Lopez-Honorez, L ; Mena, O ; Rigolin, S
Publication	2010
Imprint	04 May 2010
Note	Comments: 16 pages, 2 figures
Subject category	Astrophysics and Astronomy
Abstract	We study a coupled dark energy-dark matter model in which the energy-momentum exchange is proportional to the Hubble expansion rate. The inclusion of its perturbation is required by gauge invariance. We derive the linear perturbation equations for the gauge invariant energy density contrast and velocity of the coupled fluids, and we determine the initial conditions. The latter turn out to be adiabatic for dark energy, when assuming adiabatic initial conditions for all the standard fluids. We perform a full Monte Carlo Markov Chain likelihood analysis of the model, using WMAP 7-year data.
Other source	Inspire