On the Asymptotic Character of Electromagnetic Waves in a   Friedmann-Robertson-Walker Universe
  Asymptotic properties of electromagnetic waves are studied within the context of Friedmann-Robertson-Walker (FRW) cosmology. Electromagnetic fields are considered as small perturbations on the background spacetime and Maxwell's equations are solved for all three cases of flat, closed and open FRW universes. The asymptotic character of these solutions are investigated and their relevance to the problem of cosmological tails of electromagnetic waves is discussed. 
Nader Haghighipour