X-ray emission from isolated neutron stars

TL;DR

X-ray observations have significantly advanced the understanding of isolated neutron stars by revealing diverse emission types, new classes, and detailed surface and magnetospheric properties across different neutron star populations.

Contribution

This paper reviews recent progress in X-ray studies of isolated neutron stars, highlighting new classes and detailed emission mechanisms uncovered by modern instruments.

Findings

Detection of thermal and non-thermal X-ray emissions in various neutron star types

Identification of new classes like X-ray Dim Isolated Neutron Stars and Central Compact Objects

Insights into surface composition and magnetic field effects

Abstract

X-ray emission is a common feature of all varieties of isolated neutron stars (INS) and, thanks to the advent of sensitive instruments with good spectroscopic, timing, and imaging capabilities, X-ray observations have become an essential tool in the study of these objects. Non-thermal X-rays from young, energetic radio pulsars have been detected since the beginning of X-ray astronomy, and the long-sought thermal emission from cooling neutron star's surfaces can now be studied in detail in many pulsars spanning different ages, magnetic fields, and, possibly, surface compositions. In addition, other different manifestations of INS have been discovered with X-ray observations. These new classes of high-energy sources, comprising the nearby X-ray Dim Isolated Neutron Stars, the Central Compact Objects in supernova remnants, the Anomalous X-ray Pulsars, and the Soft Gamma-ray Repeaters, now add up to several tens of confirmed members, plus many candidates, and allow us to study a variety of phenomena unobservable in "standard'' radio pulsars.