A NICER view of PSR J0030+0451: evidence for a global-scale multipolar magnetic field

TL;DR

NICER observations of PSR J0030+0451 suggest its magnetic field is complex and multipolar, challenging the traditional centered dipole model and impacting various pulsar studies.

Contribution

This paper reviews NICER data and explores the possibility of a global-scale multipolar magnetic field in PSR J0030+0451, moving beyond the classical dipole assumption.

Findings

Hot emitting regions are not antipodal.

No direct evidence supports a centered dipole magnetic field.

Complex magnetic configurations have significant implications for pulsar physics.

Abstract

Recent modeling of NICER observations of thermal X-ray pulsations from the surface of the isolated millisecond pulsar PSR J0030+0451 suggests that the hot emitting regions on the pulsar's surface are far from antipodal, which is at odds with the classical assumption that the magnetic field in the pulsar magnetosphere is predominantly that of a centered dipole. Here, we review these results and examine previous attempts to constrain the magnetospheric configuration of PSR J0030+0451. To the best of our knowledge, there is in fact no direct observational evidence that PSR J0030+0451's magnetic field is a centered dipole. Developing models of physically motivated, non-canonical magnetic field configurations and the currents that they can support poses a challenging task. However, such models may have profound implications for many aspects of pulsar research, including pulsar braking, estimates of birth velocities, and interpretations of multi-wavelength magnetospheric emission.