Observational tests for \Lambda(t)CDM cosmology
  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. 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.
