Radio Evolution of Pulsars

Phenomenological analysis of radio evolution of pulsars is made. Under an assumption that the period of most of pulsars have a similar time dependence, the age t of pulsars is determined statistically from the observed spindown time t1 : t=0.30t1• Period P, radio luminosity during the pulse L, called simply the luminosity, and size of the radio-emitting region a, estimated as the pulse width times the light velocity, are shown to have time dependences of PoctO.SO±o.os, Loct0.70±0,t2 and aoct0.23±0.o& respectively. This radio evolution is compared with that of supernova remnants, quasi-stellar objects and radio galaxies directly or by means of the luminosity versus volume emissivity diagram. The evolutionary tracks are similar to each other in spite of different mechanisms involved. Finally the observed luminosity function N(L) ocL-t.50±0.os is compared with that calculated from the time dependence of the luminosity and it is shown that the slopes of the both functions are consistent with each other if the selection effect in the present sample of pulsars is taken into account. Similarly the birth rate of pulsars in the Galaxy is shown to be nearly equal to the explosion rate of type II supernovae after the selection effect is taken into account.