Pulsar Wind Bubble Blowout from a Supernova

TL;DR

This paper uses 2D and 3D simulations to study how pulsar wind nebulae expand and break out from supernova ejecta, revealing conditions under which the nebula can fragment and escape, especially in magnetar-powered superluminous supernovae.

Contribution

It demonstrates the role of Rayleigh-Taylor instability in nebula expansion and identifies conditions for nebula blowout in supernova remnants, including magnetar scenarios.

Findings

Rayleigh-Taylor instability causes filamentary structures.

Nebula blowout occurs when pulsar energy exceeds supernova energy.

Crab Nebula may have originated from a low-energy supernova.

Abstract

For pulsars born in supernovae, the expansion of the shocked pulsar wind nebula is initially in the freely expanding ejecta of the supernova. While the nebula is in the inner flat part of the ejecta density profile, the swept-up, accelerating shell is subject to the Rayleigh-Taylor instability. We carried out 2 and 3-dimensional simulations showing that the instability gives rise to filamentary structure during this initial phase but does not greatly change the dynamics of the expanding shell. The flow is effectively self-similar. If the shell is powered into the outer steep part of the density profile, the shell is subject to a robust Rayleigh-Taylor instability in which the shell is fragmented and the shocked pulsar wind breaks out through the shell. The flow is not self-similar in this phase. For a wind nebula to reach this phase requires that the deposited pulsar energy be greater than the supernova energy, or that the initial pulsar period be in the ms range for a typical $10^{51}$ erg supernova. These conditions are satisfied by some magnetar models for Type I superluminous supernovae. We also consider the Crab Nebula, which may be associated with a low energy supernova for which this scenario applies.