Publication Date:
2014-08-29
Description:
We use a modified pulsar current analysis to study magnetic field decay in radio pulsars. In our approach, we analyse the flow not along the spin period axis as has been performed in previous studies, but study the flow along the direction of growing characteristic age, $\tau =P/(2\dot{P})$ . We perform extensive tests of the method and find that in most of the cases it is able to uncover non-negligible magnetic field decay (more than a few tens of per cent during the studied range of ages) in normal radio pulsars for realistic initial properties of neutron stars. However, precise determination of the magnetic field decay time-scale is not possible at present. The estimated time-scale may differ by a factor of few for different sets of initial distributions of neutron star parameters. In addition, some combinations of initial distributions and/or selection effects can also mimic enhanced field decay. We apply our method to the observed sample of radio pulsars at distances 〈10 kpc in the range of characteristic ages 8 10 4 〈 〈 10 6 yr where, according to our study, selection effects are minimized. By analysing pulsars in the Parkes Multibeam and Swinburne surveys, we find that, in this range, the field decays roughly by a factor of 2. With an exponential fit, this corresponds to the decay time-scale ~4 10 5 yr. With larger statistics and better knowledge of the initial distribution of spin periods and magnetic field strength, this method can be a powerful tool to probe magnetic field decay in neutron stars.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
