Scientists at Osaka Metropolitan University have developed a novel method for observing cosmic-ray extensive air showers with unprecedented precision, providing new opportunities to study the Universe’s most energetic particles.

High-energy cosmic rays colliding with Earth’s atmosphere generate extensive air showers, a phenomenon with an abundance of particles. Researchers led by Associate Professor Toshihiro Fujii and graduate student Fraser Bradfield from the Graduate School of Science and Nambu Yoichiro Institute of Theoretical and Experimental Physics at Osaka Metropolitan University have discovered that the Subaru Telescope’s prime-focus wide field camera, located on the Mauna Kea volcano in Hawaii, can capture these extensive air showers with exceptional resolution.

The Subaru Telescope was primarily designed for observational astronomy, and cosmic rays typically appear as “noise” or “tracks” on astronomical images, obscuring stars and galaxies. However, this research focuses on harnessing that “noise.” By analyzing around 17,000 images captured between 2014 and 2020, the team identified 13 images containing extensive air showers, showcasing a significantly larger number of particle tracks than usual.

Professor Fujii explained, “Conventional observation methods struggle to differentiate between the types of particles within extensive air showers. In contrast, our method has the potential to identify the nature of individual particles.”

He further stated, “By combining our method with traditional approaches, we aim to advance our understanding of extensive air showers. This technique could aid in the search for dark matter and other exotic particles, providing additional insights into the Universe’s transition into a matter-dominated era.”

The results of this study are scheduled for publication in Scientific Reports on October 12, 2023.