Fast Afterglows of Fast Radio Bursts

TL;DR

This paper proposes that fast radio bursts leave behind relativistic plasma that emits observable coherent electromagnetic afterglows, with a predicted decreasing frequency over time, supported by numerical experiments.

Contribution

It introduces a novel model for FRB afterglows based on collisionless plasma relaxation and demonstrates this with numerical simulations.

Findings

Numerical demonstration of fast coherent afterglows.

Predicted afterglow frequency decreases as t^{-3/2}.

Potential observability of FRB afterglows.

Abstract

The main FRB event may leave behind a clump of relativistic plasma with high ``free energy'' density. As the plasma undergoes collisionless relaxation, it emits coherent electromagnetic waves. These electromagnetic waves may be observable as a fast radio afterglow, with decreasing frequency and intensity. We demonstrate the fast coherent afterglow in a numerical experiment. We tentatively predict the peak afterglow frequency decreasing with time as $\nu \propto t^{-3/2}$.