Search for extragalactic techno-signatures with MeerKAT

Yuri Uno^1*, Tetsuya Hashimoto¹, James Chibueze², Daniel Czech³, Tomotsugu Goto⁴

¹Department of Physics, NCHU, Taichung, Taiwan
²Mathematical Science, Univeristy of South Africa, Pretoria, South Africa
³Astrophysics, Oxford University, Oxford, UK
⁴Institute of Astronomy, NTHU, Hsinchu, Taiwan

* Presenter:Yuri Uno, email:yuri.uno@smail.nchu.edu.tw

Astrobiology explores the origins and evolution of life, with the Search for Extraterrestrial Intelligence (SETI) traditionally focused on detecting technosignatures within the Milky Way. The historical non-detection of technosignatures over the past sixty years may be attributed to the limited scope of searches, which have predominantly targeted individual stars within the Milky Way. This study expands SETI efforts to galaxy clusters, considering the potential for more advanced civilizations as proposed by the Kardashev scale. This method allows us to observe roughly ten orders of magnitude more stars than surveys focusing on individual stars in the Milky Way. By targeting galaxy clusters, we aim to enhance our ability to detect potential technosignatures. However, the luminosity function of extraterrestrial radio transmitters remains unknown. Using the MeerKAT telescope in South Africa, we observed galaxy clusters from July to September 2023. The data was processed using the Breakthrough Listen User Supplied Equipment (BLUSE) to identify narrowband radio signals indicative of artificial origins. Although no definitive alien signals were confirmed, our research marks the first-ever SETI exploration of galaxy clusters, setting the first constraint on the upper limit of the transmitter rate at the bright end. This pioneering effort significantly expands our search scope beyond the Milky Way, enhancing the potential for discovering advanced extraterrestrial life. Although no signals have been detected thus far, this research opens a new frontier in the quest for intelligent life beyond our galaxy.

Keywords: Astrobiology, SETI, Galaxy Cluster