Fast Radio Bursts from non-resonant Alfv\'en waves and synchrotron maser emission in the magnetar wind

TL;DR

This paper proposes a mechanism involving non-resonant Alfvén waves and synchrotron maser emission in magnetar winds to explain the origin of fast radio bursts, linking observed properties to magnetar environment conditions.

Contribution

It introduces a novel model for FRB generation via non-resonant Alfvén wave interactions in magnetar winds, connecting emission characteristics to magnetar properties and activity.

Findings

Relativistic magnetar winds can produce FRB frequencies and energies.

Wind Lorentz factors of ≥310 are required to match observations.

Magnetar properties like period and magnetic field align with observed FRB sources.

Abstract

Non-resonant interactions between Alfv\'en waves and a relativistic plasma result in the formation of the population inversions necessary for synchrotron maser emission (SME) across a wide range of magnetisations and temperatures. We calculate the peak frequencies of the SME resulting from this interaction and show that the characteristic frequencies and energetics of fast radio bursts (FRBs) can be produced in the relativistic wind of a magnetar using this mechanism. Wind Lorentz factors of $\gamma_w\gtrsim310$ are shown to be necessary to explain observed FRBs. Emission is possible at temperatures of $\theta = k_bT/mc^2\lesssim 0.02$. We further examine the periods and magnetic fields of the central magnetar and demonstrate that the optimal values of these properties align with the observed magnetar population provided that the magnetosphere is disturbed by the flaring activity. These results allow the properties of the environment such as temperature and magnetisation to be probed from the observed FRB frequency and luminosity.