The common fundamental plane of X-ray emissions from pulsars and magnetars in quiescence

Magnetars are a unique class of neutron stars characterized by their incredibly strong magnetic fields. Unlike normal pulsars whose X-ray emission was driven by rotational energy loss, magnetars exhibit distinct X-ray emissions thought to be driven by their strong magnetic fields. Here, we present the results of magnetar X-ray spectra analysis in their quiescent state. In the sample studied in this paper, spectra of 17 magnetars can be fitted well with a model consisting of a power-law and a blackbody component. We found that the luminosity of the power-law component can be described by a function of blackbody temperature and emission-region radius. The same relation was seen in pulsars whose X-ray emission mechanism is thought to be different. The fact that these magnetars and pulsars share a common fundamental plane in the space spanned by non-thermal X-ray luminosity, surface temperature, and the radius of the thermally emitting region presents both challenges and hints to theoretical models for a complete comprehension of the magnetospheric emissions from these two classes of neutron stars.

Automated summary

Magnetars are a unique class of neutron stars with incredibly strong magnetic fields. Unlike normal pulsars, magnetars exhibit distinct X-ray emissions driven by their strong magnetic fields. This paper presents the results of X-ray spectra analysis of magnetars in their quiescent state. The analysis found a common fundamental plane in the space composed of non-thermal X-ray luminosity, surface temperature, and the radius of the thermally emitting region, which challenges and hints at theoretical models for understanding the magnetospheric emissions from these two classes of neutron stars.