Effective growth of matter density fluctuations in the running LCDM and LXCDM models

Details Effective growth of matter density fluctuations in the running LCDM and LXCDM models Effective growth of matter density fluctuations in the running LCDM and LXCDM models

2007-09-13

arxiv.org/abs/0709.2130v3

JCAP 0712:007,2007

Astronomy and Astrophysics

Astrophysics

General Relativity and Quantum Cosmology

LaTeX, 38 pages, 8 figures. Version accepted in JCAP

Scientific paper

10.1088/1475-7516/2007/12/007

We investigate the matter density fluctuations \delta\rho/\rho for two dark energy (DE) models in the literature in which the cosmological term \Lambda is a running parameter. In the first model, the running LCDM model, matter and DE exchange energy, whereas in the second model, the LXCDM model, the total DE and matter components are conserved separately. The LXCDM model was proposed as an interesting solution to the cosmic coincidence problem. It includes an extra dynamical component, the "cosmon" X, which interacts with the running \Lambda, but not with matter. In our analysis we make use of the current value of the linear bias parameter, b^2(0)= P_{GG}/P_{MM}, where P_{MM} ~ (\delta\rho/\rho)^2 is the present matter power spectrum and P_{GG} is the galaxy fluctuation power spectrum. The former can be computed within a given model, and the latter is found from the observed LSS data (at small z) obtained by the 2dF galaxy redshift survey. It is found that b^2(0)=1 within a 10% accuracy for the standard LCDM model. Adopting this limit for any DE model and using a method based on the effective equation of state for the DE, we can set a limit on the growth of matter density perturbations for the running LCDM model, the solution of which is known. This provides a good test of the procedure, which we then apply to the LXCDM model in order to determine the physical region of parameter space, compatible with the LSS data. In this region, the LXCDM model is consistent with known observations and provides at the same time a viable solution to the cosmic coincidence problem.

Affiliated with

Also associated with

No associations

Rating

Effective growth of matter density fluctuations in the running LCDM and LXCDM models 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 Effective growth of matter density fluctuations in the running LCDM and LXCDM models, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Effective growth of matter density fluctuations in the running LCDM and LXCDM models will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-215381