Exploring the circumstellar environment of Tycho's supernova remnant. II. Impact on the broadband non-thermal emission

TL;DR

This study models Tycho's supernova remnant environment, incorporating dense molecular clouds and wind-like circumstellar matter, to analyze its impact on non-thermal emission and compare with observed multi-wavelength spectra.

Contribution

It extends previous work by integrating non-thermal emission modeling with a complex circumstellar environment, highlighting discrepancies and future observational predictions.

Findings

Broadband spectrum aligns with observations but predicts a harder gamma-ray spectrum.

Low CSM density in the model's cavity interior affects gamma-ray predictions.

Clumpy, multi-dimensional CSM structure may resolve spectral discrepancies.

Abstract

While the environment around Tycho's supernova remnant (SNR) has long been believed to be close to homogeneous, the latest analysis of Chandra data has identified a substantial deceleration of the forward shock which poses a major challenges to this picture. arXiv:2310.14841 showed that the existence of dense molecular cloud (MC) surrounding a rarefied wind-like circumstellar matter (CSM) can explain this observational finding in term of the shock-expansion dynamics, supporting the so-called single-degenerate scenario for the progenitor system. We here extend this work to study the non-thermal emission processes and investigate whether such an environment is consistent with the observed multi-wavelength spectrum. While the simulated broadband spectrum based on the wind-MC environment is largely consistent with observations, we find that such an environment predicts a harder gamma-ray spectrum than observed due to the relatively low CSM density in the cavity interior of the MC. This difference can be at least partially attributed to the present one-dimensional setup of the model which does not account for the clumpy and multi-dimensional structure of the CSM. Our model provides predictions for the long-term evolution of the broadband spectrum which can be used to further probe Tycho's surrounding environment in the future, a key to resolving the long-standing issue of type Ia supernova progenitor channels.