Observational tests for Λ(t)CDM cosmology

• Published in: Journal of cosmology and astroparticle physics Vol. 2011; no. 8; p. 022
• Main Authors: Pigozzo, C, Dantas, M.A, Carneiro, S, Alcaniz, J.S
• Format: Journal Article
• Language: English
• Published: United States IOP Publishing 01.08.2011
• Subjects: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGICAL CONSTANT; COSMOLOGICAL MODELS; COSMOLOGY; DISTANCE; ENERGY DENSITY; ENERGY SPECTRA; NONLUMINOUS MATTER; RELICT RADIATION; SUPERNOVAE; VISIBLE RADIATION
• ISSN: 1475-7516; 1475-7516
• DOI: 10.1088/1475-7516/2011/08/022

We investigate the observational viability of a class of cosmological models in which the vacuum energy density decays linearly with the Hubble parameter, resulting in a production of cold dark matter particles at late times. Similarly to the flat ΛCDM case, there is only one free parameter to be adjusted by the data in this class of Λ(t)CDM scenarios, namely, the matter density parameter. To perform our analysis we use three of the most recent SNe Ia compilation sets (Union2, SDSS and Constitution) along with the current measurements of distance to the BAO peaks at z = 0.2 and z = 0.35 and the position of the first acoustic peak of the CMB power spectrum. We show that in terms of χ{sup 2} statistics both models provide good fits to the data and similar results. A quantitative analysis discussing the differences in parameter estimation due to SNe light-curve fitting methods (SALT2 and MLCS2k2) is studied using the current SDSS and Constitution SNe Ia compilations. A matter power spectrum analysis using the 2dFGRS is also performed, providing a very good concordance with the constraints from the SDSS and Constitution MLCS2k2 data.