Slide 12 of 59
Notes:
It is interesting to note that the lifetime of a pulsar, tau = P/2(dP/dt) for the Crab Nebula is about 1400 years - and this was observed to explode in 1054. The continuous supply of high energy particles from the pulsar to the surrounding nebula explains the observed energy output levels from the nebula since the original explosion.
The Crab pulsar (P=33 millisec) and the Vela pulsar (P=89 millisec) have been detected at radio, IR , optical, X-ray and g-ray wavelengths. Other pulsars tend to be only radio emitters.
Over 500 pulsars are now known and all of them are in our Galaxy except for one in the Large Magellanic Cloud and one in the Small Magellanic Cloud.