Sofia Sheikh (Pennsylvania State University)

Sofia Sheikh Colloquium: The Breakthrough Listen Signal-of-Interest 'blc1'

Online

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.