On the supernova remnants produced by pulsars.

Abstract

It is concluded that pulsar-driven supernova remnants (SNRs) are extremely rare objects. Indeed, an analysis of the known sample of plerions suggests a very low birthrate (about 1 in 240 years). Long-lived and bright plerions like the Crab nebula are likely to be produced only when the pulsar has an initial period of about 10-20 milliseconds and a field of about one trillion G. Such pulsars inside rapidly expanding shell remnants should also produce detectable plerions. The extreme rarity of SNRs with such hybrid morphology leads to the conclusion that these pulsars must have been born with an initial period larger than about 35-70 milliseconds.