Large scale extragalactic jets powered by very-high energy gamma rays

Abstract

The radiative cooling of electrons responsible for the nonthermal synchrotron emission of large scale jets of radiogalaxies and quasars requires quasi continuous (in time and space) production of relativistic electrons throughout the jets over the scales exceeding 100 kpc. While in the standard paradigm of large scale jets this implies in situ acceleration of electrons, in this letter we propose a principally different ``non-acceleration'' origin of these electrons, assuming that they are implemented all over the length of the jet through effective development of electromagnetic cascades initiated by extremely high energy gamma-rays injected into the jet from the central object. This scenario provides a natural and very economic way to power the jets up to distances of 100 kpc and beyond.