Magnetic fields of neutron stars: very low and very high

TL;DR

This paper reviews magnetic field estimations of neutron stars, comparing observational data with theoretical models, and discusses discrepancies and alternative interpretations, especially for X-ray pulsars and magnetars.

Contribution

It provides a comprehensive comparison of magnetic field estimates from observations and theory for various neutron star types, highlighting discrepancies and proposing alternative explanations.

Findings

Good correspondence between observed and theoretical magnetic fields for radio pulsars.

Discrepancy between cyclotron line estimates and long-term observational data for Her X-1.

Alternative interpretation of cyclotron features may resolve the discrepancy.

Abstract

Estimations of magnetic fields of neutron stars, observed as radio and X-ray pulsars, are discussed. It is shown, that theoretical and observational values for different types of radiopulsars are in good correspondence. Magnetic fields of X-ray pulsars are estimated from the cyclotron line energy. In the case of Her X-1 this estimation exceeds considerably the value of its magnetic field obtained from long term observational data related to the beam structure evolution. Another interpretation of the cyclotron feature, based on the relativistic dipole radiation mechanism, could remove this discrepancy. Observational data about soft gamma repeators and their interpretation as magnetars are analyzed.