On the decay of the magnetic fields of single radio pulsars

Abstract

We investigate the statistical evidence for the decay of the magnetic field of single radio pulsars. We perform population syntheses for different assumed values for the time scale of field decay using a Monte Carlo method. We allow for the selection effects in pulsar surveys and compare the synthesized populations with the observed pulsars. We take account of the finite scale height of the distribution in the Galaxy of free electrons, which determine the dispersion measure and hence the apparent distance of radio pulsars. Our simulations give much better agreement with the observations if the time scale for the field decay is assumed to be longer than the typical active life time of a radio pulsar. This indicates that no significant field decay occurs in single radio pulsars.