Scientists at Osaka Metropolitan University used the Subaru Telescope to observe the cosmic ray array with unprecedented clarity. This new method could lead to major discoveries about the universe, including insights into dark matter. SubaruHyperSuprime-Cam observed a large-scale air shower of cosmic rays with unprecedented precision.
Showers in the bathroom bring us comfort, while showers from space bring joy to astrophysicists. Scientists at Osaka Metropolitan University have used their novel method to observe large-scale flows of cosmic rays with unprecedented precision, opening a new door to our understanding of the most energetic particles in the universe.
When high-energy cosmic rays collide with the Earth's atmosphere, they create large amounts of particles known as widespread rain. A research team led by Associate Professor Toshihiro Fujii and graduate student Fraser Bradfield of Osaka Metropolitan University Graduate School of Science and Nanbu Yoichiro Institute for Theoretical Physics found that the original focus wide-field camera installed on the Subaru Telescope atop Hawaii's Mauna Kea volcano can capture these large-scale airflows with extremely high resolution.
An example of a widespread shower of cosmic rays recorded by the Subaru Telescope. The highlighted trajectories are mostly aligned in similar directions, showing gas rain particles induced by high-energy cosmic rays. Source: National Astronomical Observatory of Japan, HyperSuprime-Cam (HSC) Collaboration Group
Subaru telescopes are designed for observational astronomy. Cosmic rays appear as "trajectories" on observation images, obscuring target stars or galaxies, and are treated as noise by common astronomical data processing methods. However, it is this "noise" that the team's research focuses on. By analyzing about 17,000 images taken between 2014 and 2020, the team identified 13 images that contained large amounts of airflow. The images show a far greater number of particle trajectories than usual.
Professor Fujii explains: "Conventional observational methods have difficulty distinguishing the types of particles that make up large-scale gas showers. Our method makes it possible to determine the properties of individual particles." He added: "Furthermore, by combining our method with traditional methods, we hope to deepen our understanding of large-scale gas flows. This technique may allow us to search for dark matter or other exotic particles, providing more information about the transition of the universe to a matter-dominated era."
Their research results will be published in Scientific Reports on October 12, 2023.