Division of Science, NAOJ

High-energy gamma-ray and neutrino emissions from supernovae: Constraint on cosmic-ray production efficiency by using radiation hydrodynamic simulations

Our universe is filled with cosmic rays, high-energy protons and atomic nuclei. However, where and how these cosmic rays are accelerated remains one of the major unsolved mysteries in astrophysics. One of the most promising candidates for the origin of cosmic ray acceleration is supernova remnants—structures left behind after supernova explosions. It is believed that cosmic rays are accelerated by shock waves formed when the matter ejected during a supernova collides with the surrounding interstellar gas. Recent observations of supernova explosions have revealed that extremely dense circumstellar material ubiquitously exists around exploding stars. When the ejected matter from the supernova collides with this dense material, strong shock waves are generated, which can accelerate cosmic rays. These accelerated cosmic rays then interact with the dense circumstellar material, producing gamma rays and neutrinos. By observing these gamma rays and neutrinos, we may be able to identify the sites and mechanisms of cosmic ray acceleration.A research team, Shigeo KIMURA at FRIS, Tohoku University and Takashi MORIYA at Division of Science, NAOJ, developed a new method to calculate neutrino and gamma-ray emissions produced when a supernova explosion interacts with dense circumstellar material. Applying this method to SN 2023ixf—a supernova that occurred in a nearby galaxy in 2023—they succeeded in placing constraints on the efficiency of cosmic ray production. Using radiation-hydrodynamic simulations, the team reproduced the structure of the circumstellar material and the ejecta from the explosion that matched optical observations of SN 2023ixf. Based on this simulation data, they constructed a framework to compute gamma-ray and neutrino emissions. The calculations revealed that if the cosmic ray production efficiency were greater than 10%, it would contradict the fact that current gamma-ray telescopes did not detect any signals from SN 2023ixf. This method will be applied to multiple supernovae in the future, potentially revealing the efficiency of cosmic ray production at shock fronts.These results are published in The Astrophysical Journal on May 2nd, 2025.

Publication information
Title: High-energy gamma-ray and neutrino emissions from interacting supernovae based on radiation hydrodynamic simulations: a case of SN 2023ixf
Authors: Shigeo S. Kimura, Takashi J. Moriya
Journal: The Astrophysical Journal
DOI：10.3847/1538-4357/adc716
URL：https://iopscience.iop.org/article/10.3847/1538-4357/adc716

Press release from Tohoku University: https://www.fris.tohoku.ac.jp/en/feature/topics/detail—id-1558.html