# Spectral Variability Signatures of Relativistic Shocks in Blazars

## TL;DR

This paper models spectral variability signatures of relativistic shocks in blazars, incorporating time dependence and multiple emission zones, to predict multiwavelength flare behaviors and time lags.

## Contribution

It extends previous shock acceleration models by including full time dependence and multiple zones, applied to real blazar flare data.

## Key findings

- Predicted spectral hysteresis patterns in energy bands.
- Identified cross-band time lags with specific lag times.
- Modeled multiwavelength flare behaviors in blazars.

## Abstract

Mildly relativistic, oblique shocks are frequently invoked as possible sites of relativistic particle acceleration and production of strongly variable, polarized multi-wavelength emission from relativistic jet sources such as blazars, via diffusive shock acceleration (DSA). In recent work, we had self-consistently coupled DSA and radiation transfer simulations in blazar jets. These one-zone models determined that the observed spectral energy distributions (SEDs) of blazars strongly constrain the nature of the hydromagnetic turbulence responsible for pitch-angle scattering. In this paper, we expand our previous work by including full time dependence and treating two emission zones, one being the site of acceleration. This modeling is applied to a multiwavelength flare of the flat spectrum radio quasar 3C~279, fitting snap-shot SEDs and light curves. We predict spectral hysteresis patterns in various energy bands as well as cross-band time lags with optical and GeV gamma-rays as well as radio and X-rays tracing each other closely with zero time lag, but radio and X-rays lagging behind the optical and gamma-ray variability by several hours.