The connection between blazars and compact radio sources

Abstract

It is argued that the unresolved VLBI-cores in flat spectrum, compact radio sources have properties very similar to the associated blazar emission region: Large scale magnetic field, anisotropic pitch-angle distribution and the importance of relativistic streaming motion. Problems afflicting models invoking Compton-cooling behind a relativistic shock in a jet to explain the initial phase of out-bursts in the mm/far-infrared regime are discussed. As an alternative, a qualitative discussion is given of a model where relativistic streaming and pitch-angle scattering are the main ingredients.