AN ASSOCIATION BETWEEN A LONG-PERIOD PULSAR AND AN OLD SUPERNOVA REMNANT

THE birth of neutron stars is expected to be accompanied by supernovae of types Ib and II (which constitute the majority). But only a few associations between neutron stars and supernova remnants are known1; most involve young pulsars with short periods. Older supernova remnants should also be accompanied by pulsars, but these would be less luminous and, because they would have spun down to longer periods, they would beam to a much smaller fraction of the sky2. This may explain why no associations of this sort have been detected previously3. Here we report a possible such association: between pulsar 2334 + 61, with a relatively long period of 0.5 s, and G114.3 + 0.3, a fairly old supernova remnant. The flat spectral index of -0.36 +/- 0.03 (refs 4, 5) and large fractional polarization suggest that the radio emission is powered by the pulsar. If so, the pulsar must have been born with a relatively short period of less than 100 ms. As the remnant is not particularly unusual morphologically, there might be many more such remnants containing pulsars that are not beamed towards us.