Xavier Siemens, a renowned astrophysicist and professor at Oregon State’s College of Science, has been awarded the prestigious 2025 Bruno Rossi Prize, one of the highest international honors in high-energy astrophysics, for his groundbreaking work uncovering evidence of binary supermassive black holes.
Siemens shares the honor with Maura McLaughlin and the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) Physics Frontiers Center whose achievement in gravitational wave research marks a significant step forward in understanding the dynamics of the Universe and its deep mysteries.
In June 2023, Siemens led an international team of nearly 200 researchers, including OSU students, in detecting low-frequency gravitational waves reverberating across the universe—ripples in spacetime first predicted by Albert Einstein over a century ago. This discovery provided the first direct evidence of the stochastic gravitational wave background, caused by merging binary supermassive black holes.
NANOGrav announced their groundbreaking discovery in June 2023. The news was picked up around the world including by the New York Times, Nature, Reuters, AP News, The Guardian, The Washington Post, BBC, NPR and more.
"We are incredibly proud of Dr. Siemens," said Dean Eleanor Feingold. "The Bruno Rossi Prize is one of the most prestigious honors in high-energy astrophysics and places him among the world’s leading scientists. His groundbreaking achievements continue to inspire his students, who pursue the universe’s most profound questions with his mentorship."
Presented annually by the High Energy Division of the American Astronomical Society, the Bruno Rossi Prize recognizes exceptional contributions to high-energy astrophysics. Awarded since 1985, this prize is highly regarded in the astrophysics community, often highlighting work that pushes the boundaries of our understanding of the universe. The award will be formally presented at the next HEAD meeting, where Siemens and his collaborators will deliver a lecture on their findings.
Siemens’ achievements not only advance the field of astrophysics but also inspire the next generation of scientists, including graduate and undergraduate students at Oregon State, where he continues to mentor and conduct research that pushes the boundaries of human knowledge.
