Detection of ultra-fast radio bursts from FRB 20121102A

TL;DR

This paper reports the discovery of ultra-fast, microsecond-duration radio bursts from FRB 20121102A, revealing a previously undetected population of fast bursts that challenges existing detection methods and enhances understanding of FRB emission mechanisms.

Contribution

It demonstrates that FRB 20121102A can produce microsecond bursts and identifies a population of ultra-fast FRBs missed by current surveys, advancing knowledge of FRB diversity and detection.

Findings

FRB 20121102A produces microsecond bursts

Ultra-fast bursts are similar in polarization to longer bursts

Current searches miss a population of ultra-fast FRBs

Abstract

Fast radio bursts (FRBs) are extragalactic transients with typical durations of milliseconds. FRBs have been shown, however, to fluctuate on a wide range of timescales: some show sub-microsecond sub-bursts while others last up to a few seconds in total. Probing FRBs on a range of timescales is crucial for understanding their emission physics, how to detect them effectively, and how to maximize their utility as astrophysical probes. FRB 20121102A is the first-known repeating FRB source. Here we show that FRB 20121102A is able to produce isolated microsecond-duration bursts whose total durations are more than ten times shorter than all other known FRBs to date. The polarimetric properties of these micro-bursts resemble those of the longer-lasting bursts, suggesting a common emission mechanism producing FRBs spanning a factor of 1,000 in duration. Furthermore, this work shows that there exists a population of ultra-fast radio bursts that current wide-field FRB searches are missing due to insufficient time-resolution. These results indicate that FRBs occur more frequently and with greater diversity than initially thought. This could also influence our understanding of energy, wait time, and burst rate distributions.