Note: Joaquin Vieira is Co-Chair of SkAI Pillar 3 (Learning-Based Astrophysical Survey and Instrument Design)
By NCSA News Staff (National Center for Supercomputing Applications, January 20, 2026)
The universe is vast, but astronomers don’t have to look too far to find something genuinely new. Researchers at the Center for AstroPhysical Surveys (CAPS) used the South Pole Telescope to probe one of the most complex regions of the sky, the crowded inner Milky Way, and uncovered powerful, short-lived bursts of millimeter-wavelength light from two known accreting white dwarf systems. In a region where overlapping sources, dust, and confusion can make discovery difficult, these flashes stood out clearly and point to a class of energetic events that millimeter surveys are uniquely positioned to reveal.
The events, reported in a recent paper in The Astrophysical Journal, represent the first time such flares have been discovered in a wide-field, time-domain millimeter survey. That distinction matters: rather than targeting a pre-selected list of candidate objects, the survey repeatedly scanned a large swath of the Galactic Plane and caught the flares serendipitously. The result demonstrates that high-cadence millimeter mapping can do more than measure static emission. They can also detect fast, rare transients and open a new observational window on the dynamic astrophysics of the Milky Way’s central environments.
“We’re just starting to understand what’s possible,” said Yujie Wan, lead author of the study and graduate student in the Department of Astronomy at the University of Illinois Urbana-Champaign. “There is so much happening at the center of our galaxy that we’ve never been able to observe at these wavelengths. This discovery is the first step toward a much richer picture of the Milky Way.”
The detections came from the SPT-3G Galactic Plane Survey, the first dedicated high-sensitivity, wide-field, time-domain, millimeter survey of the Galactic Plane. Using the 10-meter South Pole Telescope, the team repeatedly observed a roughly 100-square-degree region toward the Galactic Center in three millimeter bands. Over multiple seasons, the survey accumulated hundreds of repeated observations of the same patch of sky—enough to notice day-scale variability and to distinguish genuine astrophysical flares from noise, weather, or instrumental effects. Analysis of the first two years of data alone revealed two distinct transient events, highlighting both the rarity of the phenomenon and the power of persistent, systematic monitoring.
Unlike previous SPT surveys that focus on cleaner, high-latitude fields optimized for cosmology, the Galactic Plane Survey intentionally targets a different and much denser volume of the Milky Way. By looking toward the inner galaxy, the survey probes regions with far higher source density and richer astrophysical complexity, where compact objects, star formation and extreme environments are more common. That strategy improves the odds of catching bright events at larger distances, but it also raises the bar for data processing and validation. The field is crowded, the backgrounds vary and distinguishing a transient point source from complex extended emission requires careful analysis.
Researchers at CAPS, based at the National Center for Supercomputing Applications (NCSA), collaborated with an international team to develop the analysis necessary to identify transients: sudden, short-lived bursts of emission that appear and fade on timescales of hours to days. In this case, each flare lasted roughly one day. While that might sound long compared to milliseconds-long radio bursts, it’s brief in the context of most astronomical variability and places strong constraints on the size and physical mechanism of the emitting region. Importantly, the events were detected in millimeter bands where transient discovery has historically been far less common than in optical or X-ray surveys.
“Historically, most astrophysical transients are detected at optical or X-ray wavelengths,” said Joaquin Vieira, astronomy professor and director of CAPS. “Finding them in the millimeter band gives us a new way to study how these systems behave, especially in a region as complex and crowded as the Galactic Plane.” To read more, see https://www.ncsa.illinois.edu/2026/01/20/researchers-use-south-pole-telescope-to-detect-energetic-stellar-flares-near-the-center-of-the-milky-way/
The SkAI Institute is one of the National Artificial Intelligence Research Institutes funded by the U.S. National Science Foundation and Simons Foundation.
Information on National AI Institutes is available at aiinstitutes.org.
