Burst timescales and luminosities link young pulsars and fast radio bursts

TL;DR

This study reveals that a repeating fast radio burst (FRB) can produce extremely short, intense emission shots comparable to those from pulsars, bridging the gap between pulsars and extragalactic FRBs, and suggesting a common emission mechanism.

Contribution

It demonstrates that FRB 20200120E can produce nanosecond-scale bursts with high brightness temperatures, linking pulsars and FRBs and highlighting a potentially overlooked population of ultra-fast transients.

Findings

FRB 20200120E emits 60 nanosecond bursts with brightness temperatures up to 3×10^41 K.

The burst timescales and luminosities bridge the gap between pulsars and extragalactic FRBs.

There likely exists a population of ultra-fast radio transients at nanosecond to microsecond timescales.

Abstract

Fast radio bursts (FRBs) are extragalactic radio flashes of unknown physical origin. Their high luminosities and short durations require extreme energy densities, like those found in the vicinity of neutron stars and black holes. Studying the burst intensities and polarimetric properties on a wide range of timescales, from milliseconds down to nanoseconds, is key to understanding the emission mechanism. However, high-time-resolution studies of FRBs are limited by their unpredictable activity levels, available instrumentation and temporal broadening in the intervening ionised medium. Here we show that the repeating FRB 20200120E can produce isolated shots of emission as short as about 60 nanoseconds in duration, with brightness temperatures as high as $3\times 10^{41}$ K (excluding relativistic effects), comparable to `nano-shots' from the Crab pulsar. Comparing both the range of timescales and luminosities, we find that FRB 20200120E observationally bridges the gap between known Galactic young pulsars and magnetars, and the much more distant extragalactic FRBs. This suggests a common magnetically powered emission mechanism spanning many orders of magnitude in timescale and luminosity. In this work, we probe a relatively unexplored region of the short-duration transient phase space; we highlight that there likely exists a population of ultra-fast radio transients at nanosecond to microsecond timescales, which current FRB searches are insensitive to.