  We use lookback time versus redshift data from galaxy clusters (Capozziello
et al., 2004) and passively evolving galaxies (Simon et al., 2005), and apply a
bayesian prior on the total age of the Universe based on WMAP measurements, to
constrain dark energy cosmological model parameters. Current lookback time data
provide interesting and moderately restrictive constraints on cosmological
parameters. When used jointly with current baryon acoustic peak and Type Ia
supernovae apparent magnitude versus redshift data, lookback time data tighten
the constraints on parameters and favor slightly smaller values of the
nonrelativistic matter energy density.
