Abstract: The aim of the search for extraterrestrial
intelligence (SETI) is to find technologically-capable life beyond
Earth through their technosignatures. On 2019-April-29, the
Breakthrough Listen SETI project observed Proxima Centauri with the
Parkes "Murriyang" radio telescope. These data contained a narrowband
signal with characteristics broadly consistent with a technosignature
near 982 MHz (colloquially named 'blc1'). In this talk, I will
present the discovery and characterization of blc1 in the context of
the ubiquity of human-generated radio interference. Briefly: we find
that blc1 is not an extraterrestrial technosignature, but rather an
electronically-drifting intermodulation product of local, time-varying
interferers aligned with the observing cadence. We find dozens of
instances of radio interference with similar morphologies to blc1 at
harmonically-related frequencies to common clock oscillators. These
complex intermodulation products highlight the necessity for detailed
follow-up of any signal-of-interest. I will end the talk with a
discussion of the necessity of signal verification procedures, and
lessons learned from this intriguing case study.
|