Speaker
Description
The TeV-bright blazars induce cosmological beam-plasma instabilities through the emission of gamma rays: The gamma rays annihilate on the infrared-ultraviolet extra-galactic background light (EBL) producing electron/positron pair-beams which drive the growth of linearly unstable beam-plasma waves during their propagation through the ionized intergalactic medium (IGM). This results in depositing the pair-beams energy into the IGM in form of plasma waves and eventually into thermal energy. Another possible mechanism that could dominate the energy loss of these pair-beams is the inverse Compton cascades (ICC) with the Cosmic microwave background (CMB) photons. This lead to the production of photons with GeV energies.
During the linear regime of the blazar-driven beam-plasma instabilities, the energy loss due to these instabilities greatly exceed that via ICC. However, due to uncertainties in the non-linear evolution of the instabilities, the dominance of the ICC mechanism is still a possibility. Each of these two mechanisms have a different physical implication for the thermal history of the IGM, affecting our understanding of cosmological structure formation, interpretation of Ly-$\alpha$ forest, etc.
In this talk, I will highlight our ongoing effects to probe different signatures of these two possibilities.
