A Shock-in-Jet Synchrotron Mirror Model for Blazars

TL;DR

This paper develops a shock-in-jet model with a synchrotron mirror component to explain orphan gamma-ray flares in blazars, successfully reproducing mild orphan flares observed in 3C279 and enhancing understanding of high-energy variability.

Contribution

It introduces a novel synchrotron mirror component into the shock-in-jet model, addressing the challenge of modeling orphan flares in blazars.

Findings

Orphan flares can naturally arise from the synchrotron mirror scenario.

The model reproduces mild orphan gamma-ray flares in 3C279.

Only modest enhancements of the Compton dominance are needed for the model to match observations.

Abstract

Reinhard Schlickeiser has made groundbreaking contributions to various aspects of blazar physics, including diffusive shock acceleration, the theory of synchrotron radiation, the production of gamma-rays through Compton scattering in various astrophysical sources, etc. This paper, describing the development of a self-consistent shock-in-jet model for blazars with a synchrotron mirror feature, is therefore an appropriate contribution to a Special Issue in honor of Reinhard Schlickeiser's 70th birthday. The model is based on our previous development of a self-consistent shock-in-jet model with relativistic thermal and non-thermal particle distributions evaluated via Monte-Carlo simulations of diffusive shock acceleration, and time-dependent radiative transport. This model has been very successful in modeling spectral variability patterns of several blazars, but has difficulties describing orphan flares, i.e., high-energy flares without a significant counterpart in the low-frequency (synchrotron) radiation component. As a solution, this paper investigates the possibility of a synchrotron mirror component within the shock-in-jet model. It is demonstrated that orphan flares result naturally in this scenario. The model's applicability to a recently observed orphan gamma-ray flare in the blazar 3C279 is discussed and it is found that only orphan flares with mild ($\lesssim$ a factor of 2 - 3) enhancements of the Compton dominance can be reproduced in a synchrotron-mirror scenario, if no additional parameter changes are invoked.