On the evolution of high-B radio pulsars with measured braking indices

TL;DR

This study models the long-term evolution of high-magnetic field radio pulsars with measured braking indices, showing their properties can be explained by fallback disc evolution and predicting their future transition into normal pulsars or accretion phases.

Contribution

It applies a fallback disc evolution model to high-B radio pulsars, explaining their properties and evolutionary paths, which was not previously done for this specific pulsar class.

Findings

HBRPs' properties can be explained by fallback disc evolution.

Magnetic fields of HBRPs are comparable to or greater than AXP/SGRs.

HBRPs will likely evolve into normal pulsars or accretion phases within 10^4 years.

Abstract

We have investigated the long-term evolutions of the high-magnetic field radio pulsars (HBRPs) with measured braking indices in the same model that was applied earlier to individual anomalous X-ray pulsars (AXPs), soft gamma repeaters (SGRs) and dim isolated neutron stars (XDINs). We have shown that the rotational properties (period, period derivative and braking index) and the X-ray luminosity of individual HBRPs can be acquired simultaneously by the neutron stars evolving with fallback discs. The model sources reach the observed properties of HBRPs in the propeller phases, when pulsed radio emission is allowed, at ages consistent with the estimated ages of the supernova remnants of the sources. Our results indicate that the strength of magnetic dipole fields of HBRPs are comparable to and even greater than those of AXP/SGRs and XDINs, but still one or two orders of magnitude smaller than the values inferred from the magnetic dipole torque formula. The possible evolutionary paths of the sources imply that they will lose their seemingly HBRP property after about a few 10^4 yr, because either their rapidly decreasing period derivatives will lead them into the normal radio pulsar population, or they will evolve into the accretion phase switching off the radio pulses.