Radio Bursts with Extragalactic Spectral Characteristics Show Terrestrial Origins

TL;DR

This study reports 16 terrestrial-origin radio pulses with extragalactic-like spectral features detected in a telescope sidelobe, challenging previous assumptions of their extragalactic nature and emphasizing the need for improved detection methods.

Contribution

The paper demonstrates that signals previously thought to be extragalactic bursts can originate terrestrially, highlighting the importance of multi-detector approaches for accurate identification.

Findings

16 terrestrial-origin pulses with extragalactic-like spectra detected

Original extragalactic burst interpretation is questioned

Emphasizes need for multi-detector radio-pulse surveys

Abstract

Three years ago, the report of a solitary radio burst was thought to be the first discovery of a rare, impulsive event of unknown extragalactic origin (Lorimer et al. 2007). The extragalactic interpretation was based on the swept-frequency nature of the event, which followed the dispersive delay expected from an extragalactic pulse. We report here on the detection of 16 pulses, the bulk of which exhibit a frequency sweep with a shape and magnitude resembling the Lorimer Burst. These new events were detected in a sidelobe of the Parkes Telescope and are of clearly terrestrial origin, with properties unlike any known sources of terrestrial broad-band radio emission. The new detections cast doubt on the extragalactic interpretation of the original burst, and call for further sophistication in radio-pulse survey techniques to identify the origin of the anomalous terrestrial signals and definitively distinguish future extragalactic pulse detections from local signals. The ambiguous origin of these seemingly dispersed, swept-frequency signals suggest that radio-pulse searches using multiple detectors will be the only experiments able to provide definitive information about the origin of new swept-frequency radio burst detections.