Particle acceleration, escape, and non-thermal emission from core-collapse supernovae inside non-identical wind-blown bubbles

Abstract

Context. In the core-collapse scenario, supernova remnants (SNRs) evolve inside complex wind-blown bubbles structured by massive progenitors during their lifetime. Therefore, particle acceleration and the emissions from these SNRs can carry the fingerprints of the evolutionary sequences of the progenitor stars. Aims. We investigate the impact of the ambient environment of core-collapse SNRs on particle spectra and emissions for two progenitors with different evolutionary tracks while accounting for the spatial transport of cosmic rays (CRs) and the magnetic turbulence that scatters CRs. Methods. We used the RATPaC code to model the particle acceleration at the SNRs with progenitors having zero-age main sequence (ZAMS) masses of 20 M⊙ and 60 M⊙. We constructed the pre-supernova circumstellar medium (CSM) by solving the hydrodynamic equations for the lifetime of the progenitor stars. Then, the transport equation for cosmic rays, the magnetic turbulence in test-particle approximation, and the induction equation for the evolution of a large-scale magnetic field were solved simultaneously with the hydro-dynamic equations for the expansion of SNRs inside the pre-supernova CSM in 1-D spherical symmetry. Results. The profiles of gas density and temperature of the wind bubbles along with the magnetic field and the scattering turbulence regulate the spectra of accelerated particles for both of the SNRs. For the 60 M⊙ progenitor, the spectral index reaches 2.4, even below 10 GeV, during the propagation of the SNR shock inside the hot shocked wind. In contrast, we did not observe a persistent soft spectra at earlier evolutionary stages of the SNR with the 20 M⊙ progenitor, for which the spectral index becomes 2.2 only for a brief period during the interaction of SNR shock with the dense shell of red supergiant (RSG) wind material. At later stages of evolution, the spectra become soft above ~10 GeV for both SNRs, as weak driving of turbulence permits the escape of high-energy particles from the remnants. The emission morphology of the SNRs strongly depends on the type of progenitors. For instance, the radio morphology of the SNR with the 20 M⊙ progenitor is centre-filled at early stages, whereas that of the more massive progenitor is shell-like.