Three-dimensional Global Relativistic Radiation Magnetohydrodynamics of Magnetically Arrested Disk Accretion Flows in AGNs

TL;DR

This study uses 3D radiation-relativistic MHD simulations to analyze how black hole spin affects magnetically arrested disk accretion flows in AGNs, revealing minimal influence on flow dynamics and spectral energy distribution.

Contribution

It demonstrates that black hole spin has little effect on the dynamics and radiation properties of MAD accretion flows in AGNs, using comprehensive 3D simulations with radiation processes.

Findings

MAD state persists across all spins

Flow dynamics are similar regardless of spin

Total luminosity exceeds synchrotron and bremsstrahlung luminosities

Abstract

We perform three-dimensional radiation-relativistic magnetohydrodynamic (3D Rad-RMHD) simulations of accretion flows around spinning active galactic nuclei (AGNs). Our study focuses on the magnetically arrested disk (MAD) state, adopting a single-temperature model that includes bremsstrahlung opacity as the sole radiation process while varying the black hole spin from non-spinning to rapidly spinning cases. We find that the MAD state persists across all spin values, as demonstrated by the normalized magnetic flux at the horizon and the physically motivated spatially averaged plasma beta. The overall flow dynamics remain qualitatively similar for all spin models in 3D flow, suggesting that black hole spin has minimal influence on the accretion dynamics. In addition, we conduct post-processing using a two-temperature model to calculate the luminosities from synchrotron and bremsstrahlung radiation. We find that the total radiation luminosity is significantly higher than the luminosities from synchrotron and bremsstrahlung. This finding highlights the influence of radiation on the dynamics of the accretion flow. Our analysis shows that the electron temperature is significantly high in the jet region, regardless of spin. We further find that the temporal evolution of both radiative and synchrotron luminosities exhibits qualitatively similar behavior across all spin values. Finally, our results indicate that black hole spin has minimal impact on the spectral energy distribution (SED) in MAD state accretion flows.