Secular evolution of galaxies and galaxy clusters in decaying dark
  matter cosmology
  If the dark matter sector in the universe is composed by metastable
particles, galaxies and galaxy clusters are expected to undergo significant
secular evolution from high to low redshift. We show that the decay of dark
matter, with a lifetime compatible with cosmological constraints, can be at the
origin of the observed evolution of the Tully-Fisher relation of disk galaxies
and alleviate the problem of the size-evolution of elliptical galaxies, while
being consistent with the current observational constraints on the gas fraction
of clusters of galaxies.
