A Steady-State Spectral Model For Electron Acceleration And Cooling In Blazar Jets: Application To 3C 279

TL;DR

This paper develops a comprehensive spectral model for electron acceleration and cooling in blazar jets, successfully explaining the spectrum of 3C 279 and highlighting the importance of stratified broad line regions and stochastic acceleration.

Contribution

It introduces a detailed one-zone leptonic model incorporating multiple acceleration and cooling processes, with a novel numerical boundary condition technique, applied to 3C 279.

Findings

Stratified broad line region improves emission region distance estimates.

Stochastic acceleration supplies more energy than shock acceleration.

Jet is not always in equipartition between particles and magnetic field.

Abstract

We introduce a new theoretical model to describe the emitting region in a blazar jet. We assume a one-zone leptonic picture, and construct the particle transport equation for a plasma blob experiencing low-energy, monoenergetic particle injection, energy dependent particle escape, shock acceleration, adiabatic expansion, stochastic acceleration, synchrotron radiation, and external Compton radiation from the dust torus and broad line region. We demonstrate that a one-zone leptonic model is able to explain the IR though {\gamma}-ray spectrum for 3C 279 in 2008-2009. We determine that the broad-line region seed photons cannot be adequately described by a single average distribution, but rather we find that a stratified broad line region provides an improvement in the estimation of the distance of the emitting region from the black hole. We calculate that the jet is not always in equipartition between the particles and magnetic field, and find that stochastic acceleration provides more energy to the particles than does shock acceleration, where the latter is also overshadowed by adiabatic losses. We further introduce a novel technique to implement numerical boundary conditions and determine the global normalization for the electron distribution, based on analysis of stiff ordinary differential equations. Our astrophysical results are compared with those obtained by previous authors.