Open AccessA late‐time transition in the cosmic dark energy?
Author(s) -
Bassett Bruce A.,
Kunz Martin,
Silk Joseph,
Ungarelli Carlo
Publication year - 2002
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 - 10.1046/j.1365-8711.2002.05887.x
Subject(s) - physics , cosmic microwave background , dark energy , redshift , astrophysics , supernova , cosmic background radiation , acceleration , cosmic cancer database , cosmology , galaxy , quantum mechanics , anisotropy
We study constraints from the latest cosmic microwave background (CMB), large‐scale structure (2dF, Abell/ACO, PSC z ) and SN1a data on dark energy models with a sharp transition in their equation of state, w ( z ) . Such a transition is motivated by models like vacuum metamorphosis where non‐perturbative quantum effects are important at late times. We allow the transition to occur at a specific redshift, z t , to a final negative pressure −1 ≤ w f < −1/3 . We find that the CMB and supernovae data, in particular, prefer a late‐time transition because of the associated delay in cosmic acceleration. The best fits ( ±1 σ errors) to all the data are z t = 2.0 +2.2 −0.76 , Ω Q = 0.73 +0.02 −0.04 and w f =−1 +0.2 . For z t > 5 the likelihood becomes flat, asymptoting to the standard ΛCDM model.