11 radio stations at Argentina’s Pierre Auger Observatory are being adapted from cosmic-ray measurements to lightning observations. A single instrumentation preprint describes longer signal capture and an initial direction measurement compatible with a thunderstorm. The partly commissioned network aims to explore lightning’s timing against gamma-ray flashes; a definitive simultaneous association has not yet been obtained.
At Argentina’s Pierre Auger Observatory, eleven radio stations formerly used for cosmic-ray measurements are being adapted to follow lightning. The new BOLT network is intended to reconstruct three-dimensional lightning radio signals and compare their timing with terrestrial gamma-radiation flashes. A single instrumentation preprint submitted on 7 October describes the conversion and its first tests; the network remains partly commissioned.[1]
The antennas cover radio frequencies from 30 to 80 megahertz. Cosmic-ray observations captured short signal segments, whereas a lightning discharge requires much longer waveforms. New software uses a circular memory buffer to retain the relevant signal after a trigger. The controller’s transfer rate constrains extraction of these larger measurements, and additional storage is still under development.[1]
Station spacing varies from a compact central group to remote sites as far as sixty kilometres apart. This arrangement supports timing measurements and reconstruction across different spatial scales. Central and intermediate installations advanced in 2024 and 2025, while relocation of four remote stations took place during spring 2026.[1]
A complete one-second waveform was acquired in the field. An initial lightning candidate also yielded a direction compatible with the same thunderstorm region. This checks recording and directional reconstruction, but does not establish a definitive simultaneous match with a gamma-ray flash. Remote commissioning and storage work continue alongside the first measurements.[1]
