Modeling Multiple X-Ray Reflection in Super-Eddington Winds

Abstract

It has been recently discovered that a few super-Eddington sources undergoing black hole super-Eddington accretion exhibit X-ray reflection signatures. In such new systems, one expects the coronal X-ray emissions to be mainly reflected by optically thick super-Eddington winds instead of thin disks. In this paper, we conduct a series of general-relativistic ray-tracing and Monte Carlo radiative transfer simulations to model the X-ray reflection signatures, especially the characteristic Fe K α line, produced from super-Eddington accretion flows around nonspinning black holes. In particular, we allow the photons emitted by a lamppost corona to be reflected multiple times in a cone-like funnel surrounded by fast winds. We find that the Fe K α line profile most sensitively depends on the wind kinematics, while its exact shape also depends on the funnel open angle and corona height. Furthermore, very interestingly, we find that the Fe K α line can have a prominent double-peak profile in certain parameter spaces, even with a face-on orientation. Moreover, we compare the Fe K α line profiles produced from super-Eddington and thin disks and show that such lines can provide important insights into the understanding of black hole systems undergoing super-Eddington accretion.

Keywords

• Accretion
• X-ray binary stars
• X-ray active galactic nuclei
• Black hole physics
• Radiative transfer simulations
• Monte Carlo methods