The Effect of a Variable Diffusion Coefficient on the Cutoff Spectra of Shock Accelerated Particles

Abstract

Recent observations in the infrared frequency range show that many extragalactic radio sources exhibit a very steep spectral cutoff around 3 – 1014 Hz These spectra are most likely produced by synchrotron radiating highly energetic electrons. The first order Fermi mechanism can provide an answer to the question of the origin of these particles. Considering a momentum and spatial depending diffusion coefficient, electron distributions can be achieved producing synchrotron spectra which are in very good agreement with the observed ones.