Long-term Evolution of Nonthermal Emission from Type Ia and Core-collapse Supernova Remnants in a Diversified Circumstellar Medium

Abstract

The contribution of galactic supernova remnants (SNRs) to the origin of cosmic rays (CRs) is an important open question in modern astrophysics. Broadband nonthermal emission is a useful proxy for probing the energy budget and production history of CRs in SNRs. We conduct hydrodynamic simulations to model the long-term SNR evolution from explosion all the way to the radiative phase (or 3 × 105 yr at maximum) and compute the time evolution of the broadband nonthermal spectrum to explore its potential applications on constraining the surrounding environments, as well as the natures and mass-loss histories, of the SNR progenitors. A parametric survey is performed on the ambient environments separated into two main groups, namely, a homogeneous medium with a uniform gas density and one with the presence of a circumstellar structure created by the stellar wind of a massive red supergiant progenitor star. Our results reveal a highly diverse evolution history of the nonthermal emission closely correlated to the environmental characteristics of an SNR. Up to the radiative phase, the roles of CR reacceleration and ion−neutral wave damping on the spectral evolution are investigated. Finally, we make an assessment of the future prospect of SNR observations by the next-generation hard X-ray space observatory FORCE and predict what we can learn from their comparison with our evolution models.