The Light Curve and Internal Magnetic Field of the Mode-Switching Pulsar PSR B0943+10

TL;DR

This paper investigates the mode-switching behavior of pulsar PSR B0943+10, explaining its X-ray pulse fraction through magnetic atmosphere beaming effects and exploring complex magnetic field configurations, aligning models with current radio and X-ray data.

Contribution

It introduces models incorporating magnetic atmosphere beaming and displaced dipole configurations to explain observed X-ray pulse fractions in PSR B0943+10.

Findings

Magnetic atmosphere beaming explains large X-ray pulse fractions.

Displaced dipole models produce asymmetric polar caps consistent with observations.

Models can be tested with future X-ray observations.

Abstract

A number of radio pulsars exhibit intriguing mode-switching behavior. Recent observations of PSR B0943+10 revealed correlated radio and X-ray mode switches, providing a new avenue for understanding this class of objects. The large X-ray pulse fraction observed during the radio quiet phase (Q mode) was previously interpreted as a result of changing obscuration of X-rays by dense magnetosphere plasma. We show that the large X-ray pulse fraction can be explained by including the beaming effect of a magnetic atmosphere, while remaining consistent with the dipole field geometry constrained by radio observations. We also explore a more extreme magnetic field configuration, where a magnetic dipole displaced from the center of the star produces two magnetic polar caps of different sizes and magnetic field strengths. These models are currently consistent with data in radio and X-rays and can be tested or constrained by future X-ray observations.