Constraining the Spin-down of the Nearby Isolated Neutron Star RX J2143.0+0654

TL;DR

This study measures the spin-down rate of the nearby isolated neutron star RX J2143.0+0654, constraining its magnetic field to around 2e13 G, and discusses implications for neutron star magnetic evolution and surface conditions.

Contribution

First measurement of the spin-down rate for RX J2143.0+0654, constraining its magnetic field and exploring implications for neutron star magnetic decay and surface properties.

Findings

Magnetic field likely around 2e13 G

Presence of a 0.75 keV absorption feature confirmed

Tentative evidence for an additional 0.4 keV feature

Abstract

Magnetic field estimates for nearby isolated neutron stars (INS) help to constrain both the characteristics of the population and the nature of their peculiar X-ray spectra. From a series of XMM-Newton observations of RX J2143.0+0654, we measure a spin-down rate of -4.6e-16 +/- 2.0e-16 Hz/s. While this does not allow a definitive measurement of the dipole magnetic field strength, fields of >1e14 G such as those inferred from the presence of a spectral absorption feature at 0.75keV are excluded. Instead, the field is most likely around 2e13 G, very similar to those of other INS. We not only suggest that this similarity most likely reflects the influence of magnetic field decay on this population, but also discuss a more speculative possibility that it results from peculiar conditions on the neutron-star surface. We find no evidence for spectral variability above the ~2% level. We confirm the presence of the 0.75-keV feature found earlier, and find tentative evidence for an additional absorption feature at 0.4 keV.