Dynamical Evolution and Radiative Processes of Supernova Remnants

TL;DR

This paper reviews the dynamical evolution of supernova remnants from initial ejecta interaction with circumstellar material to their eventual dissipation into the interstellar medium, highlighting radiative processes and observational signatures.

Contribution

It provides a comprehensive overview of the physical processes governing supernova remnant evolution and their radiative emissions across different phases.

Findings

Remnants evolve from adiabatic to radiative phases.

Early emission dominated by thermal X-rays and nonthermal radiation.

Optical and infrared emissions become prominent in the radiative phase.

Abstract

I outline the dynamical evolution of the shell remnants of supernovae (SNRs), from initial interaction of supernova ejecta with circumstellar material (CSM) through to the final dissolution of the remnant into the interstellar medium (ISM). Supernova ejecta drive a blast wave through any CSM from the progenitor system; as material is swept up, a reverse shock forms in the ejecta, reheating them. This ejecta-driven phase lasts until ten or more times the ejected mass is swept up, and the remnant approaches the Sedov or self-similar evolutionary phase. The evolution up to this time is approximately adiabatic. Eventually, as the blast wave slows, the remnant age approaches the cooling time for immediate post-shock gas, and the shock becomes radiative and highly compressive. Eventually the shock speed drops below the local ISM sound speed and the remnant dissipates. I then review the various processes by which remnants radiate. At early times, during the adiabatic phases, thermal X-rays and nonthermal radio, X-ray, and gamma-ray emission dominate, while optical emission is faint and confined to a few strong lines of hydrogen and perhaps helium. Once the shock is radiative, prominent optical and infrared emission is produced. Young remnants are profoundly affected by interaction with often anisotropic CSM, while even mature remnants can still show evidence of ejecta.