Supernova ejecta with a relativistic wind from a central compact object: a unified picture for extraordinary supernovae

TL;DR

This paper investigates how a relativistic wind from a central compact object interacts with supernova ejecta, leading to shell formation, instabilities, and mixing, which may explain the origins of superluminous and broad-lined Ic supernovae.

Contribution

It provides a combined analytical and numerical study of ejecta-wind interaction, revealing instability-driven mixing and energy transfer processes in supernovae.

Findings

Formation of a thin shell that expands after ejecta-wind collision

Development of Rayleigh-Taylor instability causing shell destruction

Potential explanation for superluminous and broad-lined Ic supernovae

Abstract

The hydrodynamical interaction between freely expanding supernova ejecta and a relativistic wind injected from the central region is studied in analytic and numerical ways. As a result of the collision between the ejecta and the wind, a geometrically thin shell surrounding a hot bubble forms and expands in the ejecta. We use a self-similar solution to describe the early dynamical evolution of the shell and carry out a two-dimensional special relativistic hydrodynamic simulation to follow further evolution. The Rayleigh-Taylor instability inevitably develops at the contact surface separating the shocked wind and ejecta, leading to the complete destruction of the shell and the leakage of hot gas from the hot bubble. The leaking hot materials immediately catch up with the outermost layer of the supernova ejecta and thus different layers of the ejecta are mixed. We present the spatial profiles of hydrodynamical variables and the kinetic energy distributions of the ejecta. We stop the energy injection when a total energy of $10^{52}$ erg, which is 10 times larger than the initial kinetic energy of the supernova ejecta, is deposited into the ejecta and follow the subsequent evolution. From the results of our simulations, we consider expected emission from supernova ejecta powered by the energy injection at the centre and discuss the possibility that superluminous supernovae and broad-lined Ic supernovae could be produced by similar mechanisms.