Recent Advances in the Search for Extragalactic Technosignatures Using MeerKAT

The Search for Extraterrestrial Intelligence (SETI) has traditionally focused on detecting technosignatures within the Milky Way, primarily by targeting individual stars. The lack of confirmed detections over the past six decades may, in part, reflect the limited scope of these efforts. This study expands the SETI framework to include galaxy clusters, where advanced civilizations—potentially at higher Kardashev scale levels—could reside, allowing us to probe vastly more stars than conventional galactic surveys. We utilize the MeerKAT radio interferometer in South Africa, taking advantage of its high sensitivity and wide field of view, to search for technosignatures in multiple galaxy clusters. Observations are conducted using the Breakthrough Listen User Supplied Equipment (BLUSE) system, designed for commensal SETI observations. Our search targets narrowband drifting radio signals, which are unlikely to originate from natural astrophysical processes and are therefore strong candidates for artificial origin. A dedicated analysis pipeline is used to identify such signals while effectively mitigating terrestrial radio frequency interference (RFI). While no convincing technosignature candidates were detected in the current dataset, our results place more stringent constraints on the occurrence rate of powerful narrowband transmitters. These findings inform future search strategies and demonstrate the potential of commensal SETI observations with advanced arrays like MeerKAT.