Supernova remnants with magnetars: Clues to magnetar formation

Finally, I point out the possible connection between the jets in Cas A and its X-ray point source: the jets in Cas A may indicate that the explosion was accompanied by an X-ray flash, probably powered by a rapidly rotating compact object. However, the point source in Cas A does not seem to be a rapidly rotating neutron star. This suggests that Cas A contains a neutron star that has slowed down considerably in 330 yr, requiring a dipole magnetic field of B > 5 × 1013 G. The present day lack of evidence for a relic radio pulsar wind nebula may be used to infer an even higher magnetic field of 1015 G.