The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars

TL;DR

This paper reviews the observational properties of Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars, highlighting their identification as magnetars—neutron stars powered by magnetic energy—and discusses alternative models and their astrophysical context.

Contribution

It provides a comprehensive review of recent observational data and interpretations of magnetars, emphasizing their classification and the debate over their powering mechanisms.

Findings

Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars are likely magnetars.

Magnetar model explains their high magnetic fields and emission properties.

Alternative accretion-based models are also considered.

Abstract

Two classes of X-ray pulsars, the Anomalous X-ray Pulsars and the Soft Gamma-ray Repeaters, have been recognized in the last decade as the most promising candidates for being magnetars: isolated neutron stars powered by magnetic energy. I review the observational properties of these objects, focussing on the most recent results, and their interpretation in the magnetar model. Alternative explanations, in particular those based on accretion from residual disks, are also considered. The possible relations between these sources and other classes of neutron stars and astrophysical objects are also discussed.