Relativistic Pair Beams from TeV Blazars: A Source of Reprocessed GeV Emission rather than IGM Heating

Understand

The interaction of TeV photons from blazars with the extragalactic background light produces a relativistic beam of electron-positron pairs streaming through the intergalactic medium (IGM).

• The fate of the beam energy is uncertain.
• By means of two- and three-dimensional particle-in-cell simulations, we study the non-linear evolution of dilute ultra-relativistic pair beams propagating through the IGM.
• We explore a wide range of beam Lorentz factors gamma_b>>1 and beam-to-plasma density ratios alpha<<1, so that our results can be extrapolated to the extreme parameters of blazar-induced beams (gamma_b~10^6 and alpha~10^(-15), for the most powerful blazars).