The Local Galactic Transient Survey Applied to an Optical Search for Directed Intelligence

TL;DR

This paper presents the Local Galactic Transient Survey (LGTS), demonstrating that modest optical searches can detect directed energy signals from extraterrestrial civilizations in nearby galaxies using existing telescope networks.

Contribution

The study introduces a targeted optical SETI approach using the LGTS and shows its potential to detect ETI signals with modest resources in local galaxies.

Findings

LGTS can detect laser signals from ETI in nearby galaxies.

Modest laser power is sufficient for detection with current telescope networks.

High cadence and sky coverage improve detection prospects.

Abstract

We discuss our transient search for directed energy systems in local galaxies, with calculations indicating the ability of modest searches to detect optical Search for Extraterrestrial Intelligence (SETI) sources in the closest galaxies. Our analysis follows Lubin (2016) where a messenger civilization follows a beacon strategy we call "intelligent targeting." We plot the required laser time to achieve an SNR of 10 and find the time for a blind transmission to target all stars in the Milky Way to be achievable for local galactic civilizations. As high cadence and sky coverage is the pathway to enable such a detection, we operate the Local Galactic Transient Survey (LGTS) targeting M31 (the Andromeda Galaxy), the Large Magellanic Cloud (LMC), and the Small Magellanic Cloud (SMC) via Las Cumbres Observatory's (LCO) network of 0.4 m telescopes. We explore the ability of modest searches like the LGTS to detect directed pulses in optical and near-infrared wavelengths from Extraterrestrial Intelligence (ETI) at these distances and conclude a civilization utilizing less powerful laser technology than we can construct in this century is readily detectable with the LGTS's observational capabilities. Data processing of 30,000 LGTS images spanning 5 years is in progress with the TRansient Image Processing Pipeline (TRIPP; Thomas et al. (2025)).