Fast radio bursts: do repeaters and non-repeaters originate in statistically similar ensembles?

Abstract

Fast Radio Bursts (FRBs) are the short, strong radio pulses lasting several milliseconds. They are subsequently identified, for the most part, as emanating from unknown objects at cosmological distances. At present, over one hundred FRBs have been verified, classified into two groups: repeating bursts (20 samples) and apparently non-repeating bursts (91 samples). Their origins, however, are still hotly debated. Here, we investigate the statistical classifications for the two groups of samples to see if the non-repeating and repeating FRBs have different origins by employing Anderson-Darling (A-D) test and Mann-Whitney-Wilcoxon (M-W-W) test. Firstly, by taking the pulse width as a statistical variant, we found that the repeating samples do not follow the Gaussian statistics (may belong to a χ-square distribution), although the overall data and non-repeating group do follow the Gaussian. Meanwhile, to investigate the statistical differences between the two groups, we turn to M-W-W test and notice that the two distributions have different origins. Secondly, we consider the FRB radio luminosity as a statistical variant, and find that both groups of samples can be regarded as the Gaussian distributions under the A-D test, although they have different origins according to M-W-W tests. Therefore, statistically, we can conclude that our classifications of both repeaters and non-repeaters are plausible, that the two FRB classes have different origins, or each has experienced distinctive phases or been subject to its own physical processes.

The 60 pc Environment of FRB 20180916B

“…The high brightness temperatures (T b ∼ 10 36 K) of FRBs point to coherent emission from a compact source with high energy density, and for this reason many models have invoked neutron stars, white dwarfs and/or black holes in a variety of possible settings. The fact that some FRB sources are repeating (Spitler et al 2016), whereas others appear to be one-off events (Shannon et al 2018), also raises the question of whether the phenomenon can be ascribed to a single source type, or whether there are at least two sub-populations with distinct physical natures (Cui et al 2021).…”

Earth-mass primordial black hole mergers as sources for non-repeating FRBs

“…1. The normalized cumulative distribution of q derived by using formula (9) for the samples of CHIME (purple diamond), Parkes (red circle), ASKAP (green triangle), and UTMOST (blue square), respectively.…”

“…This question remains a mystery. However, some studies seem to be inclined to suggest that FRBs should be divided into two categories intrinsically [7][8][9], namely repeating FRBs and non-repeating FRBs.…”

Reconciling the 16.35-day period of FRB 20180916B with jet precession

“…For example, the repeating FRBs have longer pulse widths and weaker radio luminosities than the non-repeating ones. Meanwhile, the "down-drifting" of frequency and multiple sub-bursts, which seem to be common in the repeating FRBs (CHIME/FRB Collaboration et al 2019;Fonseca et al 2020;Cui et al 2021), are absent in non-repeating ones.…”