Relativistic Accretion Mediated by Turbulent Comptonization

TL;DR

This paper explains the high-energy X-ray emissions in black hole and neutron star accretion flows as a result of turbulent Comptonization, which becomes significant near the Eddington Limit due to relativistic turbulence.

Contribution

It demonstrates that turbulent Comptonization explains the hard X-ray emission in relativistic accretion flows, a novel insight into high-energy astrophysical phenomena.

Findings

Turbulent Compton y-parameter approaches unity near Eddington Limit.

Turbulent Compton temperature is a significant fraction of electron rest mass energy.

Hard X-ray photons are produced via turbulent Comptonization in relativistic flows.

Abstract

Black hole and neutron star accretion flows display unusually high levels of hard coronal emission in comparison to all other optically thick, gravitationally bound, turbulent astrophysical systems. Since these flows sit in deep relativistic gravitational potentials, their random bulk motions approach the speed of light, therefore allowing turbulent Comptonization to be an important effect. We show that the inevitable production of hard X-ray photons results from turbulent Comptonization in the limit where the turbulence is trans-sonic and the accretion power approaches the Eddington Limit. In this regime, the turbulent Compton y-parameter approaches unity and the turbulent Compton temperature is a significant fraction of the electron rest mass energy, in agreement with the observed phenomena.