A Search for Transient, Monochromatic Light in a 6-deg Swath along the Galactic Plane

TL;DR

This study conducted a wide-field optical survey along the Milky Way's plane to detect monochromatic laser pulses, but found no evidence of extraterrestrial technological signals, constraining the prevalence of advanced civilizations.

Contribution

First wide-field optical search along the Galactic plane for monochromatic laser signals with high sensitivity, setting new limits on extraterrestrial technological emissions.

Findings

No unexplainable monochromatic emission detected.

Detection threshold corresponds to a 70 GW laser at 1 kpc.

Previous surveys also found no technological signals.

Abstract

We searched the Milky Way Plane along a 6-deg swath for pulses of monochromatic light as faint as 15th mag (V band) using a wide-field telescope equipped with a prism. Pulses with duration less than 1 second that occur more often than once every 10 minutes would be detected, and pulses arriving less frequently would be detected with proportionally lower probability. No unexplainable monochromatic emission, pulsed or continuous, was detected. The detection threshold corresponds to a 70 GW laser having a diffraction-limited 10-meter aperture located 1 kiloparsec away (depending on wavelength). Previous searches for laser emission from more than 5000 stars found none. Previous all-sky surveys at optical and radio wavelengths have revealed thousands of unexpected objects in the universe that exhibited extraordinary spectral emission, but none were technological. Hypotheses of our Milky Way Galaxy teeming with advanced life must be demoted.