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Title: Sub-horizon evolution of cold dark matter perturbations through dark matter-dark energy equivalence epoch

We consider a cosmological model of the late universe constituted by standard cold dark matter plus a dark energy component with constant equation of state w and constant effective speed of sound. By neglecting fluctuations in the dark energy component, we obtain an equation describing the evolution of sub-horizon cold dark matter perturbations through the epoch of dark matter-dark energy equality. We explore its analytic solutions and calculate an exact w-dependent correction for the dark matter growth function, logarithmic growth function and growth index parameter through the epoch considered. We test our analytic approximation with the numerical solution and find that the discrepancy is less than 1% for 0k = during the cosmic evolution up to a = 100.
Authors:
; ;  [1]
  1. Department of Physics, Universidade Federal do Espírito Santo, avenida Ferrari 514, 29075-910 Vitória, Espírito Santo (Brazil)
Publication Date:
OSTI Identifier:
22375829
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 10; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANALYTICAL SOLUTION; APPROXIMATIONS; CORRECTIONS; COSMOLOGICAL MODELS; EQUATIONS OF STATE; EVOLUTION; FLUCTUATIONS; FUNCTIONS; NONLUMINOUS MATTER; NUMERICAL SOLUTION; PERTURBATION THEORY; SOUND WAVES; UNIVERSE; VELOCITY