SETI (Search for Extraterrestrial Intelligence) efforts have primarily targeted stellar systems within our Galaxy, with the anticipation of discovering civilizations similar to our own (Type I as defined by the Kardashev scale). Despite six decades of persistent searching and launching over a hundred SETI projects, we have yet to achieve success. A potential reason could be the sheer vastness of the parameter space we need to explore. Or it might be time to reconsider our approach. If civilizations more advanced than ours do exist, as proposed by Nikolai Kardashev, their technosignatures could potentially be detectable with our current telescopes, even from distant galaxies. We are eager to delve into this uncharted territory: Extragalactic SETI. To start with, we have reanalyzed the Breakthrough Listen (BL) data to see how many galaxies the BL could have observed when we shift our focus from the stellar systems, the initial BL target, to the galaxies that happen to be within the beam of radio telescopes. As a result, we set the tightest upper limit on the transmitter rate: ~10^-13 within 969 Mpc above 7.7×10^26W of power, indicating civilizations transmitting powerful radio in high duty-cycle are quite few.  In the presentation, I will discuss the latest endeavors of our team in the realm of extragalactic SETI.

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