Scaling of cosmic-ray escape and acceleration parameters

Characterize how the cosmic-ray escape efficiency, diffusion coefficient, and maximum proton energy scale with supernova-remnant age and environment in middle-aged supernova remnants.

Background

The paper develops a time-dependent model of cosmic-ray acceleration, confinement, and escape and applies it to four middle-aged supernova remnants. The authors emphasize that observations spanning the GeV-to-PeV range could constrain these processes, but that a systematic understanding across remnants is not yet available. The unresolved issue concerns whether and how the escape efficiency, surrounding-medium diffusion coefficient, and maximum proton energy vary as functions of remnant age and environmental conditions.

References

Despite the wealth of data, a systematic comparison of acceleration and escape parameters across different middle-aged SNRs is still lacking. In particular, it remains unclear how the escape efficiency, diffusion coefficient, and maximum proton energy scale with SNR age and environment.

— Constraining Cosmic-Ray Acceleration and Escape in Middle-Aged Supernova Remnants with GeV-TeV Gamma-Ray Observations  (2608.18954 - Chen et al., 19 Aug 2026) in Section 2, subsection “Cosmic ray acceleration and escape from SNRs”