"Breakthrough Listen: Searching Galaxies for Signals of Advanced Civilizations"

Breakthrough Listen, the most ambitious Search for Extraterrestrial Intelligence (SETI) experiment to date, has conducted a radio technosignature search of the centers of 97 nearby galaxies using the Robert C. Byrd Green Bank Telescope. Unfortunately, no compelling evidence of extraterrestrial intelligence was found. The experiment focused on galaxies rather than individual stars, allowing for the search of millions of stars and potentially millions of stellar systems with planets. The team used a narrowband Doppler drift search at four frequencies and established constraints on the data to look for possible transmitters with the equivalent isotropic radiated power of 10,000 zetawatts. Although no technosignatures were detected, this survey represents a landmark in SETI research and will inform future searches by Breakthrough Listen.