Unifying the observational diversity of isolated neutron stars via magneto-thermal evolution models

TL;DR

This paper presents advanced 2D magneto-thermal evolution models of neutron stars, incorporating the Hall effect, to unify the observational diversity of isolated neutron stars such as magnetars and high-B pulsars.

Contribution

The study introduces the first 2D simulations including the Hall term, successfully explaining the diversity of neutron star types with a unified model based on initial conditions.

Findings

Models match observational data of 40 neutron stars.

Diversity explained by variations in initial magnetic field, mass, and envelope.

Nearly all sources align with standard theoretical expectations.

Abstract

Observations of magnetars and some of the high magnetic field pulsars have shown that their thermal luminosity is systematically higher than that of classical radio-pulsars, thus confirming the idea that magnetic fields are involved in their X-ray emission. Here we present the results of 2D simulations of the fully-coupled evolution of temperature and magnetic field in neutron stars, including the state-of-the-art kinetic coefficients and, for the first time, the important effect of the Hall term. After gathering and thoroughly re-analysing in a consistent way all the best available data on isolated, thermally emitting neutron stars, we compare our theoretical models to a data sample of 40 sources. We find that our evolutionary models can explain the phenomenological diversity of magnetars, high-B radio-pulsars, and isolated nearby neutron stars by only varying their initial magnetic field, mass and envelope composition. Nearly all sources appear to follow the expectations of the standard theoretical models. Finally, we discuss the expected outburst rates and the evolutionary links between different classes. Our results constitute a major step towards the grand unification of the isolated neutron star zoo.