A VERITAS/Breakthrough Listen Search for Optical Technosignatures

TL;DR

This study used VERITAS telescopes to search for optical technosignatures from extraterrestrial civilizations, analyzing data from 2012 to 2020, but found no signals, thereby setting limits on the prevalence of transmitting civilizations.

Contribution

First application of VERITAS telescopes for optical technosignature searches, including analysis of both new and archival data, and testing detection of pulsed laser signals from space-based sources.

Findings

No technosignatures detected in 389 observed targets.

Set upper limits on the fraction of stars with transmitting civilizations.

Validated detection techniques with CALIOP laser signals.

Abstract

The Breakthrough Listen Initiative is conducting a program using multiple telescopes around the world to search for "technosignatures": artificial transmitters of extraterrestrial origin from beyond our solar system. The VERITAS Collaboration joined this program in 2018, and provides the capability to search for one particular technosignature: optical pulses of a few nanoseconds duration detectable over interstellar distances. We report here on the analysis and results of dedicated VERITAS observations of Breakthrough Listen targets conducted in 2019 and 2020 and of archival VERITAS data collected since 2012. Thirty hours of dedicated observations of 136 targets and 249 archival observations of 140 targets were analyzed and did not reveal any signals consistent with a technosignature. The results are used to place limits on the fraction of stars hosting transmitting civilizations. We also discuss the minimum-pulse sensitivity of our observations and present VERITAS observations of CALIOP: a space-based pulsed laser onboard the CALIPSO satellite. The detection of these pulses with VERITAS, using the analysis techniques developed for our technosignature search, allows a test of our analysis efficiency and serves as an important proof-of-principle.