  The scalar and electromagnetic fields produced by the geodesic and uniformly
accelerated discrete charges in de Sitter spacetime are constructed by
employing the conformal relation between de Sitter and Minkowski space.
  A special attention is paid to new effects arising in spacetimes which, like
de Sitter space, have spacelike conformal infinities. Under the presence of
particle and event horizons, purely retarded fields (appropriately defined)
become necessarily singular or even cannot be constructed at the "creation
light cones" -- future light cones of the "points" at which the sources "enter"
the universe. We construct smooth (outside the sources) fields involving both
retarded and advanced effects, and analyze the fields in detail in case of (i)
scalar monopoles, (ii) electromagnetic monopoles, and (iii) electromagnetic
rigid and geodesic dipoles.

General Relativity and Quantum Cosmology