Parameter Comparison of Several Types of Pulsars

Abstract

We have carried out a comparative analysis of the parameters of two samples of radio pulsars. The first of them is characterized by periods $$P > 2$$ s, the second one—by the surface magnetic fields $${{B}_{s}} > 4.4 \times $$ 1013 G. The purpose for selecting these values is for the understanding the origin of the difference between normal pulsars and anomalous X-ray pulsars (AXP) and gamma-repeaters (SGR) with similar values of the periods and magnetic fields. It is shown that the derivative dependence of the period on its value $$P$$ in the long-period pulsars does not agree with the model of magneto-dipole braking and requires other mechanisms or the search for specific distributions of their parameters. In the pulsars with large magnetic fields and in AXP/SGR, this dependence does not contradict the magnetic dipole model. For pulsars with $$P > 2$$ s, the transformation efficiency of the rotation energy into the observed radiation turns out to be several times higher than for the objects with shorter periods. The pulsars with long periods have, on average, two orders of magnitude larger age than the sources with $${{B}_{s}} > 4.4 \times $$ 1013 G and AXP/SGR, and are, on average, located higher above the Galactic plane. It is concluded that the main physical parameters of the pulsars with large surface magnetic fields and their spatial distribution are close to the parameters and distribution of AXP/SGR. The comparison shows that it is not the rotation period, but the strong surface magnetic field is the decisive factor for the AXP/SGR peculiarity.