Statistical properties of fast radio bursts elucidate their origins: magnetars are favoured over gamma-ray bursts

TL;DR

This study analyzes the statistical properties of fast radio bursts (FRBs) from CHIME data, favoring magnetars over gamma-ray bursts as their likely origin, based on luminosity distributions and event rates.

Contribution

It provides the first detailed statistical analysis of FRB luminosities, constrains their origins, and suggests magnetars are the most probable sources over gamma-ray bursts.

Findings

Luminosity distribution fits Gaussian better than power-law.

Magnetars or neutron stars emitting supergiant pulses are favored as FRB sources.

A small emission beaming solid angle (~0.1 sr) is necessary for magnetars.

Abstract

Fast radio bursts (FRBs) are extremely strong radio flares lasting several milliseconds, most of which come from unidentified objects at a cosmological distance. They can be apparently repeating or not. In this paper, we analyzed 18 repeaters and 12 non-repeating FRBs observed in the frequency bands of 400-800 MHz from CHIME. We investigated the distributions of FRB isotropic-equivalent radio luminosity, considering the K correction. Statistically, the luminosity distribution can be better fitted by Gaussian form than by power-law. Based on the above results, together with the observed FRB event rate, pulse duration, and radio luminosity, FRB origin models are evaluated and constrained such that the gamma-ray bursts (GRBs) may be excluded for the non-repeaters while magnetars or neutron stars (NSs) emitting the supergiant pulses are preferred for the repeaters. We also found the necessity of a small FRB emission beaming solid angle (about 0.1 sr) from magnetars that should be considered, and/or the FRB association with soft gamma-ray repeaters (SGRs) may lie at a low probability of about 10%. Finally, we discussed the uncertainty of FRB luminosity caused by the estimation of the distance that is inferred by the simple relation between the redshift and dispersion measure (DM).