Are FRB Wandering Narrow Beams?

TL;DR

This paper explores the hypothesis that Fast Radio Bursts (FRBs) emit in narrow, wandering beams rather than isotropically, which could explain their observed properties with less extreme energy requirements.

Contribution

It introduces the idea that FRB emission may be beamed with a wandering direction, relaxing previous constraints on source models and linking FRBs to pulsar nanoshots.

Findings

Beamed emission with wandering beams can account for FRB observations.

Relaxed constraints on pulsar models due to beaming hypothesis.

Possible connection between FRBs and pulsar nanoshots.

Abstract

It is generally assumed that the sources of Fast Radio Bursts radiate roughly isotropically, so that the observed low duty cycle of any individual source indicates a similar low duty cycle of its radio-frequency emission. An alternative hypothesis is that the radiative duty cycle is ${\cal O}(1)$, but that the radiation is emitted in a beam with a solid angle comparable to the observed duty cycle, whose direction wanders or sweeps across the sky. This hypothesis relaxes the extreme power demands of isotropically radiating models of FRB at the price of multiplying the number of sources. The constraints on pulsar models are relaxed; rather than being unprecedentedly fast-spinning and highly-magnetized with short spin-down times, their parameters may be closer to those of typical radio pulsars. The nanoshots of Galactic pulsars pose analogous energetic problems that may be resolved if their emission also is beamed, suggesting a relation between these phenomena, despite their vastly different energy scales.