Paper detail

Comparison of pulsar parameters for some anomalous types

The comparative analysis of parameters is carried out for two samples of radio pulsars. Objects of the first sample have periods P > 2 sec, the second is characterized by magnetic fields at the neutron star surface $Bs > 4.4\times10^{13}$ G. The main goal of this analysis is to find some differences between normal pulsars and anomalous X-ray pulsars (AXP) and soft gamma-ray repeaters (SGR) with the similar values of periods and magnetic fields. It is shown that the dependence of period derivatives on periods for pulsars with long periods is $dP/dt \propto P^{1.67}$. This means that we must search for another braking mechanism differing from the magnetic dipole one which gives $dP/dt \propto P^{-1}$ or use some specific distributions of parameters. On the other hand, radio pulsars with strong magnetic fields and AXP/SGR can be described by the magnetic dipole model. Radio pulsars with P > 2 sec have ages on average two orders of magnitude higher than objects with $Bs > 4.4 \times 10^{13}$ G and are located much higher above the Galactic plane. The obtained results show that the main feature of AXP/SGR is the strong magnetic field and not the large period.