A bright millisecond-duration radio burst from a Galactic magnetar

TL;DR

This paper reports the detection of an extremely intense radio burst from a Galactic magnetar, providing strong evidence that magnetars can produce fast radio bursts (FRBs) similar to those observed at cosmological distances.

Contribution

The discovery of a bright radio burst from a Galactic magnetar that bridges the energy gap with extragalactic FRBs, supporting magnetars as their possible source.

Findings

Detected a two-component bright radio burst from SGR 1935+2154.

The burst energy is about 3 x 10^{34} erg, much brighter than previous magnetar radio emissions.

The event suggests magnetars can produce FRB-like signals detectable at cosmological distances.

Abstract

Magnetars are highly magnetized young neutron stars that occasionally produce enormous bursts and flares of X-rays and gamma-rays. Of the approximately thirty magnetars currently known in our Galaxy and Magellanic Clouds, five have exhibited transient radio pulsations. Fast radio bursts (FRBs) are millisecond-duration bursts of radio waves arriving from cosmological distances. Some have been seen to repeat. A leading model for repeating FRBs is that they are extragalactic magnetars, powered by their intense magnetic fields. However, a challenge to this model has been that FRBs must have radio luminosities many orders of magnitude larger than those seen from known Galactic magnetars. Here we report the detection of an extremely intense radio burst from the Galactic magnetar SGR 1935+2154 using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) FRB project. The fluence of this two-component bright radio burst and the estimated distance to SGR 1935+2154 together imply a 400-800 MHz burst energy of $\sim 3 \times 10^{34}$ erg, which is three orders of magnitude brighter than those of any radio-emitting magnetar detected thus far. Such a burst coming from a nearby galaxy would be indistinguishable from a typical FRB. This event thus bridges a large fraction of the radio energy gap between the population of Galactic magnetars and FRBs, strongly supporting the notion that magnetars are the origin of at least some FRBs.