Open AccessLarge‐scale cosmic microwave background anisotropies and dark energy
Author(s) -
Weller J.,
Lewis A. M.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2003.07144.x
Subject(s) - physics , dark energy , cosmic microwave background , equation of state , astrophysics , parametrization (atmospheric modeling) , hubble's law , cosmological constant , baryon acoustic oscillations , anisotropy , cosmology , theoretical physics , quantum mechanics , radiative transfer
In this paper we investigate the effects of perturbations in a dark energy component with a constant equation of state on large‐scale cosmic microwave background (CMB) anisotropies. The inclusion of perturbations increases the large‐scale power. We investigate more speculative dark energy models with w < −1 and find the opposite behaviour. Overall the inclusion of perturbations in the dark energy component increases the degeneracies. We generalize the parametrization of the dark energy fluctuations to allow for an arbitrary constant sound speed, and we show how constraints from CMB experiments change if this is included. Combining CMB with large‐scale structure, Hubble parameter and supernovae observations we obtain w =−1.02 ± 0.16 (1σ) as a constraint on the equation of state, which is almost independent of the sound speed chosen. With the presented analysis we find no significant constraint on the constant speed of sound of the dark energy component.