Origin of the high-energy component of blazar emission

Determine whether the high-energy component of blazar emission originates from purely leptonic synchrotron-self-Compton or external-Compton processes, proton synchrotron emission, or other hadronic processes.

Background

The paper distinguishes the low-energy component of blazar spectral energy distributions, which is generally attributed to synchrotron emission from non-thermal electrons, from the high-energy component extending from X-rays to gamma rays. It identifies several competing explanations for the high-energy emission, including synchrotron-self-Compton and external-Compton models involving relativistic electrons, as well as proton-synchrotron and other hadronic processes. The authors explicitly state that the origin of this high-energy component remains unresolved.