Late Decaying Dark Matter, Bulk Viscosity and the Cosmic Acceleration

Understand

We discuss a cosmology in which cold dark matter begins to decay into relativistic particles at a recent epoch (z < 1).

• We show that the large entropy production and associated bulk viscosity from such decays leads to an accelerating cosmology as required by observations.
• We investigate the effects of decaying cold dark matter in a Lambda = 0, flat, initially matter dominated cosmology.
• We show that this model satisfies the cosmological constraint from the redshift-distance relation for type Ia supernovae.