2006/05/31 by Christian Stephan-Otto, Christian Stephan‐Otto
Physics and Astronomy · #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.1103/physrevd.74.023507
published as Phys.Rev. D74 (2006) 023507 · 6 pages, 4 figures; typos removed and reference added to match published version
openalex publication_date 2006/07/06 · arxiv created 2006/07/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
A model-independent method to study the possible evolution of dark energy is presented. Optimal estimates of the dark energy equation of state w are obtained from current supernovae data from [A. G. Riess et al. (Supernova Search Team Collaboration), Astrophys. J. 607, 665 (2004).] following a principal components approach. We assess the impact of varying the number of piecewise constant w estimates Np using a model selection method, the Bayesian information criterion, and compare the most favored models with some parametrizations commonly used in the literature. Although data seem to prefer a cosmological constant, some models are only moderately disfavored by our selection criterion: a constant w, w\ensuremath∝a, w\ensuremath∝z, and the two-parameter models introduced here. Among these, the models we find by optimization are slightly preferred. However, current data do not allow us to draw a conclusion on the possible evolution of dark energy. Interestingly, the best fits for all varying-w models exhibit a w<\ensuremath-1 at low redshifts.