Revisiting the evolution of nonradiative supernova remnants: A hydrodynamical-informed parameterization of the shock positions

TL;DR

This paper offers highly accurate parameterizations for the evolution of supernova remnant shocks, improving upon previous models and crucial for pulsar wind nebulae studies, through analytical and numerical analysis of their structural features.

Contribution

It introduces new precise approximations for supernova remnant shock positions, enhancing the accuracy of models used in astrophysical simulations compared to prior simplified methods.

Findings

Existing approximations can lead to large errors in remnant evolution modeling.

New parameterizations improve accuracy of shock position predictions.

Self-similar solutions are approximated with high precision for early evolution phases.

Abstract

Understanding the evolution of a supernova remnant shell in time is fundamental. Such understanding is critical to build reliable models of the dynamics of the supernova remnant shell interaction with any pulsar wind nebula it might contain. Here, we perform a large study of the parameter space for the one-dimensional spherically symmetric evolution of a supernova remnant, accompanying it by analytical analysis. Assuming, as is usual, an ejecta density profile with a power-law core and an envelope, and a uniform ambient medium, we provide a set of highly-accurate approximations for the evolution of the main structural features of supernova remnants, such as the reverse and forward shocks and the contact discontinuity. We compare our results with previously adopted approximations, showing that existing simplified prescriptions can easily lead to large errors. In particular, in the context of pulsar wind nebulae modelling, an accurate description for the supernova remnant reverse shock is required. We also study in depth the self-similar solutions for the initial phase of evolution, when the reverse shock propagates through the envelope of the ejecta. Since these self-similar solutions are exact, but not fully analytical, we here provide highly-accurate approximations as well.