Radiative Particle-in-Cell Simulations of Turbulent Comptonization in Magnetized Black-Hole Coronae

Area of Science:

• Plasma physics
• Astrophysics
• High-energy astrophysics

Background:

• Accreting black hole coronae are sites of energetic particle acceleration and radiation.
• Understanding plasma turbulence is crucial for explaining observed astrophysical spectra.
• Previous models often simplified radiative transfer or plasma kinetics.

Purpose of the Study:

• To perform the first radiative particle-in-cell simulations of strong Alfvénic turbulence.
• To model the interaction of radiation with turbulent electron-positron plasmas.
• To investigate conditions relevant to magnetized coronae of accreting black holes.

Main Methods:

• Utilized 3D periodic box simulations.
• Incorporated self-consistent evolution of radiation via Compton scattering.
• Focused on strong Alfvénic turbulence in plasmas of moderate optical depth.

Main Results:

• Obtained an emission spectrum consistent with the hard state of Cyg X-1.
• Demonstrated bulk Comptonization transfers most turbulence power to photons around 100 keV.
• Showed remaining energy release into nonthermal particles creates an MeV spectral tail.

Conclusions:

• The developed method enables ab initio modeling of astrophysical sources.
• Opened a new window into kinetic plasma turbulence in astrophysical environments.
• Simulations accurately reproduce key features of black hole emission spectra.