# Determination of the Magnetic Fields of Magellanic X-Ray Pulsars

## TL;DR

This study analyzes 15 years of X-ray data from Magellanic Cloud pulsars to identify their faintest emission states, revealing five discrete groups that align with theoretical models of their magnetic fields.

## Contribution

It provides a comprehensive analysis of archival X-ray data to determine the magnetic field strengths of Magellanic X-ray pulsars through their propeller states.

## Key findings

- Faintest pulsar states form five distinct groups.
- These groups correspond to specific magnetic moments.
- Entire pulsar population can be described by five propeller lines.

## Abstract

The 80 high-mass X-ray binary (HMXB) pulsars that are known to reside in the Magellanic Clouds (MCs) have been observed by the XMM-Newton and Chandra X-ray telescopes on a regular basis for 15 years, and the XMM-Newton and Chandra archives contain nearly complete information about the duty cycles of the sources with spin periods P_S < 100 s. We have rerprocessed the archival data from both observatories and we combined the output products with all the published observations of 31 MC pulsars with P_S < 100 s in an attempt to investigate the faintest X-ray emission states of these objects that occur when accretion to the polar caps proceeds at the smallest possible rates. These states determine the so-called propeller lines of the accreting pulsars and yield information about the magnitudes of their surface magnetic fields. We have found that the faintest states of the pulsars segregate into five discrete groups which obey to a high degree of accuracy the theoretical relation between spin period and X-ray luminosity. So the entire population of these pulsars can be described by just five propeller lines and the five corresponding magnetic moments (0.29, 0.53, 1.2, 2.9, and 7.3, in units of 10^30 G cm^3).