Here is my mental picture of a de Sitter universe:
Every freely-falling observer is at the center of a personal de Sitter horizon. The de Sitter horizon cannot be approached, so the associated radiation must fill that oberver's entire universe.

I can't visualize de Sitter radiation being generated "at the de Sitter horizon" in the same way that Hawking radiation is generated at a black hole event horizon. If I understand the experts correctly, the "observer-dependent status" of the de Sitter horizon means it is not an "event horizon", and de Sitter radiation is not Hawking radiation. Maybe we can avoid worrying about virtual particle pairs at the de Sitter horizon.

Any ideas?

B. Howard