Magnetic fields of neutron stars in X-ray binaries

TL;DR

This paper reviews the magnetic fields of neutron stars in X-ray binaries, discussing their influence on accretion, emission properties, and methods for estimating their magnetic field strength, highlighting their role as natural laboratories for extreme physics.

Contribution

It provides a comprehensive review of observational aspects and estimation methods of magnetic fields in neutron star X-ray binaries, emphasizing their impact on accretion and emission behaviors.

Findings

Magnetic fields range from 10^8 to 10^13 G in these systems.

Magnetic fields significantly influence accretion processes and emission properties.

Various methods are used to estimate magnetic field strengths in neutron stars.

Abstract

A substantial fraction of the known neutron stars resides in X-ray binaries -- systems in which one compact object accretes matter from a companion star. Neutron stars in X-ray binaries have magnetic fields among the highest found in the Universe, spanning at least the range from $\sim10^8$ to several 10$^{13}$ G. The magnetospheres around these neutron stars have a strong influence on the accretion process, which powers most of their emission. The magnetic field intensity and geometry, are among the main factors responsible for the large variety of spectral and timing properties observed in the X-ray energy range, making these objects unique laboratories to study the matter behavior and the radiation processes in magnetic fields unaccessible on Earth. In this paper we review the main observational aspects related to the presence of magnetic fields in neutron star X-ray binaries and some methods that are used to estimate their strength.