Beamed Emission from a Neutron-star ULX in a GRRMHD Simulation

We perform a global 2.5D general-relativistic radiation magnetohydrodynamic simulation of supercritical accretion onto a neutron star with a 2 x 10(10) G dipolar magnetic field, as a model of a neutron-star-powered ultraluminous X-ray source (ULX). We compute a lower limit on the total luminosity of similar to 2.5 L (Edd), and find the radiation to be highly beamed by the accretion disk outflows. The apparent isotropic luminosity, which is a function of the viewing angle, reaches a maximum above 100 L (Edd), consistent with the luminosities observed in ULXs.

Automated summary

In this study, a global 2.5D general-relativistic radiation magnetohydrodynamic simulation was conducted to model supercritical accretion onto a neutron star with a 2 x 10(10) G dipolar magnetic field. The calculated lower limit of the total luminosity was approximately 2.5 times the Eddington luminosity, and the radiation was found to be highly focused by the accretion disk outflows. The apparent isotropic luminosity, dependent on the viewing angle, could reach values above 100 times the Eddington luminosity, consistent with observations in ultraluminous X-ray sources (ULXs).