A Second Source of Repeating Fast Radio Bursts

TL;DR

This paper reports the discovery of a second repeating fast radio burst (FRB) source, indicating that repeaters are more common than previously thought and sharing similar emission characteristics with the first known repeater, FRB 121102.

Contribution

The paper presents the first detection of a second repeating FRB, expanding the understanding of FRB populations and suggesting that repeaters are not rare.

Findings

Detected six repeat bursts from FRB 180814.J0422+73

Repeating bursts share characteristics with FRB 121102

Implied source distance is closer than FRB 121102

Abstract

The discovery of a repeating Fast Radio Burst (FRB) source, FRB 121102, eliminated models involving cataclysmic events for this source. No other repeating FRB has yet been detected in spite of many recent FRB discoveries and follow-ups, suggesting repeaters may be rare in the FRB population. Here we report the detection of six repeat bursts from FRB 180814.J0422+73, one of the 13 FRBs detected by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) FRB project during its pre-commissioning phase in July and August 2018. These repeat bursts are consistent with originating from a single position on the sky, with the same dispersion measure (DM), ~189 pc cm-3. This DM is approximately twice the expected Milky Way column density, and implies an upper limit on the source redshift of 0.1, at least a factor of ~2 closer than FRB 121102. In some of the repeat bursts, we observe sub-pulse frequency structure, drifting, and spectral variation reminiscent of that seen in FRB 121102, suggesting similar emission mechanisms and/or propagation effects. This second repeater, found among the first few CHIME/FRB discoveries, suggests that there exists -- and that CHIME/FRB and other wide-field, sensitive radio telescopes will find -- a substantial population of repeating FRBs.