Synchrotron emission driven by the Cherenkov-drift instability in active galactic nuclei

TL;DR

This paper investigates how Cherenkov drift instability in active galactic nuclei sustains synchrotron emission across a broad energy spectrum by balancing particle pitch angles through quasi-linear diffusion.

Contribution

It introduces a model showing Cherenkov drift waves induce quasi-linear diffusion that maintains synchrotron emission despite energy losses.

Findings

Cherenkov drift instability leads to sustained synchrotron emission.

The mechanism produces radiation from IR to soft gamma-rays.

Emission is correlated with Cherenkov drift waves across energy domains.

Abstract

In the present paper we study generation of the synchrotron emission by means of the feedback of Cherenkov drift waves on the particle distribution via the diffusion process. It is shown that despite the efficient synchrotron losses the excited Cherenkov drift instability leads to the quasi-linear diffusion (QLD), effect of which is balanced by dissipation factors and as a result the pitch angles are prevented from damping, maintaining the corresponding synchrotron emission. The model is analyzed for a wide range of physical parameters and it is shown that the mechanism of QLD guarantees the generation of electromagnetic radiation from soft $X$-rays up to soft $\gamma$-rays, strongly correlated with Cherenkov drift emission ranging from IR up to UV energy domains.