The synchrotron mechanism and the high energy flair from PKS 1510-089

TL;DR

This paper investigates how quasi-linear diffusion driven by cyclotron waves can sustain synchrotron emission in PKS 1510-089, explaining high-energy gamma-ray flares through a balance of diffusion and synchrotron reaction forces.

Contribution

It presents a kinetic model showing how feedback of cyclotron waves maintains particle pitch angles, enabling high-energy synchrotron emission in blazar PKS 1510-089.

Findings

QLD can generate GeV high-energy emission

Cyclotron modes induce synchrotron radiation in higher energy bands

Balance of forces sustains particle pitch angles for emission

Abstract

In order to understand the role of the synchrotron emission in the high energy gamma-ray flares from PKS 1510-089, we study generation of the synchrotron emission by means of the feedback of cyclotron waves on the particle distribution via the diffusion process. The cyclotron resonance causes the diffusion of particles along and across the magnetic field lines. This process is described by the quasi-linear diffusion (QLD) that leads to the increase of pitch angles and generation of the synchrotron emission. We study the kinetic equation which defines the distribution of emitting particles. The redistribution is conditioned by two major factors, QLD and the dissipation process, that is caused by synchrotron reaction force. The QLD increases pitch angles, whereas the synchrotron force resists this process. The balance between these two forces guarantees the maintenance of the pitch angles and the corresponding synchrotron emission process. The model is analyzed for a wide range of physical parameters and it is shown that the mechanism of QLD provides the generation of high energy (HE) emission in the GeV energy domain. According to the model the lower energy, associated with the cyclotron modes, provokes the synchrotron radiation in the higher energy band.