Hybrid Pulsar-Magnetar Model for FRB 20191221A

TL;DR

This paper proposes a hybrid model for FRB 20191221A, combining pulsar-like rotation with magnetic energy conversion, to explain its precise periodicity and burst characteristics.

Contribution

It introduces a pulsar-magnetar hybrid model that accounts for the observed periodicity and energy conversion mechanism of FRB 20191221A.

Findings

The FRB's periodicity is consistent with a rotating neutron star beam model.

The burst involves magnetic energy conversion, unlike typical pulsars.

The FRB is a scaled-up version of galactic pulsars with magnetic energy dominance.

Abstract

We show that the 216.8$\pm$0.1 ms periodicity reported for the fast radio burst (FRB) 20191221A is very constraining for burst models. The high accuracy of burst periodicity (better than one part in 10$^3$), and the 2\% duty cycle (ratio of burst-duration and inter-burst interval), suggest a pulsar-like rotating beam model for the observed activity; the radio waves are produced along open field lines within $\sim 10^7$ cm of the neutron star surface, and the beam periodically sweeps across the observer as the star spins. According to this picture, FRB 20191221A is a factor $\sim 10^{12}$ scaled up version of galactic pulsars with one major difference: whereas pulsars convert rotational kinetic energy to EM waves, the outbursts of 20191221A require conversion of magnetic energy to radiation.