Radio-submm flares from blazars in a discontinuous jet model

TL;DR

This paper introduces a novel model of AGN jets composed of plasma blobs that collide and accelerate electrons, producing radio to optical flares with unique spectral evolution, differing from traditional shock models.

Contribution

The model uniquely describes jets as a series of transient, colliding plasma blobs with shocks on multiple scales, differing from steady shock models like Marscher & Gear.

Findings

Successfully applied to 3C454.3 radio-submm data

Predicts different spectral evolution of flares

Implications for gamma-ray production discussed

Abstract

We present a model in which AGN jets are described by a dense series of plasma blobs, distributed in masses and velocities. The blobs expand and collide, and ultimately form a continuous jet flow as observed on larger scales. When blobs collide, energetic electrons are produced by first order Fermi acceleration, and emit synchrotron radiation at the radio-optical frequencies with a double-broken power law spectrum. The difference of this model to the well-known Marscher&Gear-model is, that in our model shocks are produced on a range of scales, and exist only temporarily, which causes differences in the prediction for the spectral evolution of flares. We apply our model to radio-submm data obtained for 3C454.3, and briefly discuss implications for gamma-ray production.