Observational tests for \Lambda(t)CDM cosmology

Understand

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 \Lambda CDM case, there is only one free parameter to be adjusted by the data in this class of \Lambda(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 $\chi^2$ statistics both models provide good fits to the data and similar results.