# Possibility of a coordinated signaling scheme in the Galaxy and SETI experiments

## TL;DR

This paper explores a galaxy-wide coordinated signaling scheme for SETI that uses astronomical events to direct signals, potentially reducing the search area significantly with gravitational-wave detectors like LISA.

## Contribution

It proposes a novel coordinated signaling scheme for SETI based on astronomical events, highlighting the potential of gravitational-wave detectors to improve search efficiency.

## Key findings

- LISA can narrow down the target sky area by a factor of 10^3-10^4.
- The scheme could be widely adopted as a tacit adjustment among civilizations.
- Signaling based on astronomical events enhances SETI search strategies.

## Abstract

We discuss a Galaxy-wide coordinated signaling scheme with which a SETI observer needs to examine a tiny fraction of the sky. The target sky direction is determined as a function of time, based on high-precision measurements of a progenitor of a conspicuous astronomical event such as a coalescence of a double neutron star binary. In various respects, such a coordinated scheme would be advantageous for both transmitters and receivers, and might be widely prevailing as a tacit adjustment. For this scheme, the planned space gravitational-wave detector LISA and its follow-on missions have a potential to narrow down the target sky area by a factor of $10^{3\textit{-}4}$, and could have a large impact on future SETI experiments.