Every night, the Zwicky Transient Facility (ZTF) scans the sky for cosmic changes, generating up to a million alerts. These alerts are processed by nine “alert brokers” – advanced software systems that identify and distribute data on anything that brightens, dims, or appears unexpectedly. The upcoming Legacy Survey of Space and Time (LSST) will amplify this data stream tenfold, presenting both an opportunity and a challenge for astronomers.

While these systems were designed to detect supernovae and asteroids, a new study by Eleanor Gallay, James Davenport and Steve Croft explores their potential for SETI (Search for Extraterrestrial Intelligence). Their research demonstrates how existing infrastructure can be adapted to search for technosignatures – subtle anomalies that might indicate artificial structures or advanced civilizations around distant stars.

The idea was partly inspired by KIC 8462852, or “Boyajian’s Star,” which exhibited unexplained dimming patterns. Though natural causes like dust clouds were eventually identified, the star’s behavior raised the possibility of artificial megastructures, such as Dyson spheres. Building on this, the team developed automated methods to detect “stellar dippers” – stars that dim suddenly without clear astrophysical explanations. The challenge lies in sifting through millions of nightly alerts to find truly anomalous signals. The researchers propose a two-step approach: first, using the brokers’ built-in filters to flag potential candidates, then applying additional analysis to historical data to identify unprecedented dimming events.

They also incorporate optical SETI techniques, such as the SETI Ellipsoid – a theoretical region where extraterrestrial observers might detect Earth transiting the Sun and potentially target signals toward us.

However, current alert brokers have limitations. While not originally designed for SETI, they can still support technosignature searches with minor modifications. For example, Lasair’s “watchmap” feature can monitor specific sky regions for anomalies. With LSST and the Vera C. Rubin Observatory set to revolutionize data volume, the team emphasizes the need for enhanced filtering methods. Their work lays the foundation for a scalable, cost-effective SETI strategy, leveraging existing sky surveys to scan millions of stars continuously.

Read the full article on Universe today.