Five new Fast Radio Bursts from the HTRU high latitude survey: first evidence for two-component bursts

TL;DR

This paper reports the discovery of five new fast radio bursts (FRBs) from the HTRU survey, including the first observed two-component FRB, providing insights into FRB rates and challenging some existing models.

Contribution

It presents the first evidence of a two-component FRB and estimates the FRB occurrence rate at high galactic latitudes, expanding understanding of FRB diversity.

Findings

Detected five new FRBs with a rate of approximately 6,000 per sky per day.

Identified the first two-component FRB with a 2.4 ms separation.

The two-component FRB has the highest dispersion measure recorded.

Abstract

The detection of five new fast radio bursts (FRBs) found in the High Time Resolution Universe high latitude survey is presented. The rate implied is 6$^{+4}_{-3}\times~10^3$ (95%) FRBs sky$^{-1}$ day$^{-1}$ above a fluence of between 0.13 and 5.9 Jy ms for FRBs between 0.128 and 262 ms in duration. One of these FRBs has a clear two-component profile, each component is similar to the known population of single component FRBs and are separated by 2.4(4) ms. All the FRB components appear to be unresolved following deconvolution with a scattering tail and accounting for intra-channel smearing. The two-component FRB also has the highest dispersion measure (1629 pc cm$^{-3}$) of any FRB to-date. Many of the proposed models to explain FRBs use a single high energy event involving compact objects (such as neutron star mergers) and therefore cannot easily explain a two-component FRB. Models that are based on extreme versions of flaring, pulsing or orbital events however could produce multiple component profiles. The compatibility of these models and the FRB rate implied by these detections is discussed.