Combined Spectrum and Anisotropy Study of Cosmic Rays from the Vela SNR with CALET

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03604
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: Waseda University
• Principal Investigator: Motz Holger 早稲田大学, 理工学術院, 教授(任期付) (30647904)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: Cosmic rays / Supernova remnants / CALET

Outline of Final Research Achievements

Galactic cosmic rays (CR) are expected to originate from supernova remnants (SNR), but as charged particles, the magnetic fields scramble their arrival direction which thus does not reveal their sources. But very high energy (TeV-range) electron CR could only arrive at Earth from a few nearby SNR (distance < 1 kpc), since they quickly loose energy.
The ISS-based CALET detector measures the spectrum of all-electron CR up into the TeV region to find signatures of these nearby SNR, specifically the Vela SNR. The theoretical spectral shape in the TeV region was studied and compared to latest results by CALET, revealing a hint for a signature from this nearby SNR.
Towards a significant discovery, improved analysis methods for the spectral and anisotropy signatures (at close distance, the CR directional information may be not completely lost, causing an increased flux from the direction of Vela) have been developed and tested with simulations, confirming that detection is likely by 2030.

Free Research Field

Cosmic ray physics

Academic Significance and Societal Importance of the Research Achievements

This project paves the road for detecting the first direct observation of cosmic rays from an individual source, the Vela SNR, which would confirm and refine our theoretical understanding of the cosmic rays' origin, leading to a more comprehensive understanding of the universe.