Published online by Cambridge University Press: 04 August 2017
The recent discovery of a central pulsing X-ray source makes MSH 15–52 the third SNR to contain a radio pulsar surrounded by diffuse X-ray emission. The pulsar periods are all increasing with time and the consequent loss of rotational kinetic energy is enough, in each remnant, to power a synchrotron nebula with the observed luminosity and volume.
After a review of the properties of the Crab Nebula it will be shown that both Vela X and MSH 15–52 have the same relationship between central pulsar and diffuse emission. Using empirical rules derived from these SNR, it is demonstrated that other plerionic remnants have similar characteristics. Two accretion-powered central sources can be distinguished from radio pulsars in SNR by the relatively high X-ray luminosity of the central source compared to that of possible synchrotron diffuse emission.