On the association between supernova remnants and pulsars

Abstract

Statistics of observed plerions (filled supernova remnants) are used here to place some constraints on the periods of pulsars at birth. Two different scenarios for the expansion of the nebular boundary are considered, using the distribution of derived magnetic field for known pulsars in both cases. From the extremely poor association between pulsar and supernova remnants and the paucity of centrally filled synchrotron nebulae, it is concluded that the majority of neutron stars must be born spinning rather slowly, with initial rotation periods greater than about 100 milliseconds.