A TESS Test of the Hybrid Ring Strategy for Technosignature Searches Using GRB 221009A

TL;DR

This paper reports the first observational test of the hybrid ring strategy for interstellar signaling, using TESS data around a bright gamma-ray burst to identify potential technosignatures within predicted arrival-time windows.

Contribution

It demonstrates the practicality of the hybrid ring strategy with existing survey data and provides a framework for future technosignature searches.

Findings

Two candidate brightenings were observed within predicted windows but are likely instrumental artifacts.

The hybrid ring strategy can be effectively tested using existing survey data like TESS.

The approach offers a promising method for future interstellar communication searches.

Abstract

We present the first observational test of the hybrid ring strategy, a general coordinated signaling scheme proposed by Seto (2025), which provides a practical Schelling-point realization for interstellar signaling. We use the exceptionally bright GRB 221009A as the anchoring flash for the scheme, together with the accurately measured distance to the Galactic center. This combination provides a high-precision relation linking sky position to a tightly constrained arrival-time window. TESS observed the region around the GRB nearly continuously for ~50 days in 2024, providing survey light curves that enable a direct test of this scheme with sharply predicted arrival-time windows of $\sim$3.4 days. Among 58 carefully selected stars, we identify two that show noticeable single-time-bin brightenings inside their predicted windows (where each time bin corresponds to a 200 s integrated TESS exposure). In both cases the brightenings coincide with excursions in at least one nearby star and are therefore most consistent with instrumental origins. This test demonstrates that the hybrid ring strategy is practical with existing survey data and could serve as a promising basis for future technosignature searches.