Magnetic field estimates for accreting neutron stars in massive binary systems and models of magnetic field decay

TL;DR

This paper investigates magnetic field decay in accreting neutron stars within Be/X-ray binaries, using observational data and modern estimation methods to test theoretical models predicting rapid initial decay followed by saturation.

Contribution

It applies advanced magnetic field estimation techniques to observational data, providing evidence supporting the theoretical decay model of Pons for highly magnetized neutron stars.

Findings

Magnetic field estimates align with Pons' decay model.

Modern estimation methods are crucial for accurate magnetic field assessment.

Results support rapid initial decay and subsequent saturation of neutron star magnetic fields.

Abstract

Some modern models of neutron star evolution predict that initially large magnetic fields rapidly decay down to some saturation value $\sim {\rm few}\times 0^{13}$ G and weaker magnetic fields do not decay significantly (Pons). It is difficult to check the predictions of this model for initially highly magnetized objects on the time scale of a few million years. We propose to use Be/X-ray binaries for this purpose. We apply several methods to estimate magnetic fields of neutron stars in these accreting systems using the data obtained by the RXTE satellite (Galache). Only using the most modern approach for estimating the magnetic field strengths of long period NSs as proposed by Shakura we are able to obtain a field distribution compatible with predictions of the theoretical model of field decay of Pons.