Evidence for Shocks as the Origin of Gamma-Ray Flares in Blazars

TL;DR

This paper provides observational and simulation evidence that oblique shocks in blazar jets are a key mechanism driving gamma-ray flares, linking radio and gamma-ray activity.

Contribution

It introduces new radiative transfer simulations with oblique shocks and turbulent magnetic fields to explain spectral evolution during flares.

Findings

Shocks produce characteristic spectral signatures during radio and gamma-ray flares.

Simulations successfully replicate observed spectral evolution during flares.

Oblique shocks are a plausible cause of gamma-ray activity in blazars.

Abstract

We present centimeter-band total flux density and linear polarization light curves illustrating the signature of shocks during radio band outbursts associated in time with gamma-ray flares detected by the Fermi LAT. The general characteristics of the spectral evolution during these events is well-explained by new radiative transfer simulations incorporating propagating oblique shocks and assuming an initially turbulent magnetic field. This finding supports the idea that oblique shocks in the jet are a viable explanation for activity from the radio to the gamma-ray band in at least some gamma-ray flares.