An Avalanche of Cosmic Events: Rubin Observatory Releases Its First Alerts

On 24 February, the Vera Rubin Observatory began issuing its first public stream of scientific alerts, automatically reporting changes detected in the night sky. During its first night of operations, the observatory generated around 800,000 alerts: signals of moving asteroids, exploding stars, and distant cosmic events. Once fully operational, the system is expected to produce up to seven million alerts per night.

While astronomical surveys of transient phenomena have existed before, Rubin operates on a completely new scale. With its 8.4-meter primary mirror and the largest digital camera ever built for astronomy (3,200 megapixels), it repeatedly scans vast areas of the sky with exceptional depth and speed. The result is a data flow unlike anything previously experienced in astronomy.

At the Center for Astrophysics and Cosmology (CAC) at the University of Nova Gorica, researchers have been preparing for this transition for years. Prof. dr. Andreja Gomboc, principal investigator of the UNG LSST team and leader of the university’s in-kind contribution to the Rubin collaboration, reflects on the milestone: “The scale of what Rubin is showing us is extraordinary, and with the alert stream we are only at the very beginning of seeing the dynamic Universe in motion.”

The Rubin Observatory, located on Cerro Pachón in Chile, is US led project, with participation also from international research teams. It will survey the entire southern sky every few nights for a decade as part of the Legacy Survey of Space and Time (LSST). Every 40 seconds it captures a new image; within about two minutes, automated systems compare it with previous observations and issue alerts whenever something has changed.

Studying cosmic explosions and black holes

Researchers at CAC focus especially on transients, short-lived cosmic phenomena such as supernova explosions and tidal disruption events, when a star is torn apart by a supermassive black hole – an event which produces a bright flare of light.

Catching such rare events early is crucial. Eduardo Concepción, a PhD student at CAC/UNG, has together with Dr. Saptashwa Bhattacharyya developed a software tool called POTICA to help identify promising black hole flares among large volumes of data. “With millions of alerts every night, we need intelligent systems to help us find the rare and extreme events,” says Concepción. “POTICA was created to spot potential black hole flares as early as possible, so we can trigger follow-up observations and study them in detail.”

Machine learning and the data revolution

Processing millions of nightly alerts requires advanced computational methods and machine learning. CAC researchers, including postdoctoral fellows supported by the EU MSCA Cofund SMASH programme, UNG-led initiative connecting astronomy and artificial intelligence, are developing tools for automated anomaly detection and class discovery. These approaches allow scientists to identify both known phenomena and entirely new types of cosmic events.

Dr. Gabriella Contardo, SMASH fellow at UNG, highlights the scientific potential: “Among the millions of alerts, there may be events we have never seen before. Rubin gives us the opportunity not only to study known phenomena in greater detail, but also to discover entirely new classes of astrophysical events.” She adds: “We have to rely on machine learning and artificial intelligence to process and analyze that quantity of data in a high-level fashion, as it is simply not doable manually; it is serendipitous that it is exactly now when these technologies are on the rise!"

Dr. Oleksandra Razim, also a SMASH fellow at UNG, emphasizes the broader transformation: “It is an exciting time to study the Universe as a dynamic environment. Rubin will provide an exceptionally rich picture of the changing sky, on timescales of days or even hours, across an unprecedented number of astronomical objects.”

Over the next decade, Rubin is expected to record tens of billions of astronomical observations, creating an ultra-high-definition time-lapse record of the southern sky.

Participation in this global scientific endeavour places the University of Nova Gorica among the institutions contributing to one of the most ambitious astronomy projects ever undertaken.

-> Video
-> Rubin press release