Cascades from Absorbed TeV Light: How Much of the GeV Background Is Reprocessed Blazar Emission?

Some of the gamma rays absorbed on the extragalactic background light do not disappear: the pairs they produce re-radiate at lower energies, returning part of the absorbed power to the GeV background as cascade emission. This paper estimates that returned fraction from the blazar TeV energy budget, a stated absorbed fraction and a stated cascade efficiency, and sets it beside a magnetic-field time-delay scale for the cascade. It finds cascade fraction of GeV background approx = 0.0814; delay at 1e-16G yr = 1.000e+04. The cascade is a percent-to-tens-of-percent correction to the blazar budget, large enough to matter for precision accounting and small enough not to disturb the overall composition. The study is simulated and computed, not measured.