Modeling Multiple X-Ray Reflection in Super-Eddington Winds

TL;DR

This study models X-ray reflection signatures, especially the Fe Kα line, from super-Eddington accretion flows around black holes, revealing how wind kinematics and geometry influence observable spectral features.

Contribution

It introduces detailed simulations of multiple X-ray reflections in super-Eddington winds, highlighting the impact of wind dynamics and geometry on Fe Kα line profiles, a novel approach in this context.

Findings

Fe Kα line profile depends on wind kinematics

Double-peak Fe Kα lines can occur in face-on views

Line profiles differ between super-Eddington and thin disks

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 that the coronal X-ray emissions are 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$\alpha$ line, produced from super-Eddington accretion flows around non-spinning 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$\alpha$ 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$\alpha$ line can have a prominent double-peak profile in certain parameter spaces even with a face-on orientation. Moreover, we compare the Fe K$\alpha$ 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.