Inhomogeneous models of interacting dark matter and dark energy

Abstract

We derive and analyze a class of spherically symmetric cosmological models whose source is an interactive mixture of inhomogeneous cold dark matter (DM) and a generic homogeneous dark energy (DE) fluid. If the DE fluid corresponds to a quintessense scalar field, the interaction term can be associated with a well motivated non--minimal coupling to the DM component. By constructing a suitable volume average of the DM component we obtain a Friedman evolution equation relating this average density with an average Hubble scalar, with the DE component playing the role of a repulsive and time-dependent $\Lambda$ term. Once we select an ``equation of state'' linking the energy density ($\mu$) and pressure ($p$) of the DE fluid, as well as a free function governing the radial dependence, the models become fully determinate and can be applied to known specific DE sources, such as quintessense scalar fields or tachyonic fluids. Considering the simple equation of state $p=(\gamma -1)\mu$ with $0\le \gamma <2/3$, we show that the free parameters and boundary conditions can be selected for an adequate description of a local DM overdensity evolving in a suitable cosmic background that accurately fits current observational data. While a DE dominated scenario emerges in the asymptotic future, with total $\Omega$ and $q$ tending respectively to 1 and -1/2 for all cosmic observers, the effects of inhomogeneity and anisotropy yield different local behavior and evolution rates for these parameters in the local overdense region. We suggest that the models presented can be directly applied to explore the effects of various DE formalisms on local DM cosmological inhomogeneities.

arXiv comment15 pages, revtex4, 10 eps figures

References in corpus (13)

• Cosmological Imprint of an Energy Component with General Equation of State
• Cosmological Constant - the Weight of the Vacuum
• Coupled Quintessence
• Interacting Quintessence
• Tests of the Accelerating Universe with Near-Infrared Observations of a High-Redshift Type Ia Supernova
• Scaling Cosmology
• Enlarged quintessence cosmology
• LIMITS ON ANISOTROPY AND INHOMOGENEITY FROM THE COSMIC BACKGROUND RADIATION,
• Alternative Dark Energy Models: An Overview
• Dark energy, dissipation and the coincidence problem
• Anisotropic Observations in Universes with Nonlinear Inhomogeneity
• An exact model of conformal quintessence
• Inhomogeneous cosmologies with Q-matter and varying $\Lambda$

Cited by in corpus (10)

• Interacting Holographic Viscous Dark Energy Model
• Quasi-local variables in spherical symmetry: numerical applications to dark matter and dark energy sources
• A single model of interacting dark energy: generalized phantom energy or generalized Chaplygin gas
• Interacting phantom dark energy: new accelerating scaling attractors
• Interactive mixture of inhomogeneous dark fluids driven by dark energy: a dynamical systems analysis
• Reconstruction of the interaction term between dark matter and dark energy using SNe Ia
• Thermodynamics of the inhomogeneous perfect fluid LTB model: Modified Bekenstein-Hawking system
• Schwarzschild black hole in dark energy background
• Comment on "Szekeres universes with homogeneous scalar fields"
• Evolution equations dynamical system of the Lemaître--Tolman--Bondi metric containing coupled dark energy