A Bright Millisecond Radio Burst of Extragalactic Origin

TLDR

Pulsar surveys enable monitoring of the radio sky for rare millisecond‑duration burst‑like events. A 30‑Jy, <5‑ms dispersed burst was detected 3° from the Small Magellanic Cloud, inconsistent with Galactic or SMC origin, implying a distance <1 Gpc; its singularity in 90 h of follow‑up suggests a catastrophic event such as a supernova or relativistic merger, and the potential daily rate of similar bursts could make them valuable cosmological probes.

Abstract

Pulsar surveys offer a rare opportunity to monitor the radio sky for impulsive burst-like events with millisecond durations. We analyzed archival survey data and found a 30-jansky dispersed burst, less than 5 milliseconds in duration, located 3 degrees from the Small Magellanic Cloud. The burst properties argue against a physical association with our Galaxy or the Small Magellanic Cloud. Current models for the free electron content in the universe imply that the burst is less than 1 gigaparsec distant. No further bursts were seen in 90 hours of additional observations, which implies that it was a singular event such as a supernova or coalescence of relativistic objects. Hundreds of similar events could occur every day and, if detected, could serve as cosmological probes.