An Extension of the Athena++ Code Framework for Radiation-Magnetohydrodynamics in General Relativity Using a Finite-Solid-Angle Discretization

Abstract

We extend the general-relativistic magnetohydrodynamics (GRMHD) capabilities of Athena++ to incorporate radiation. The intensity field in each finite-volume cell is discretized in angle, with explicit transport in both space and angle properly accounting for the effects of gravity on null geodesics, and with matter and radiation coupled in a locally implicit fashion. Here we describe the numerical procedure in detail, verifying its correctness with a suite of tests. Motivated in particular by black hole accretion in the high-accretion-rate, thin-disk regime, we demonstrate the application of the method to this problem. With excellent scaling on flagship computing clusters, the port of the algorithm to the GPU-enabled AthenaK code now allows the simulation of many previously intractable radiation-GRMHD systems.

To be published in ApJS

References in corpus (16)

• Modelling the behaviour of accretion flows in X-ray binaries
• The Athena++ Adaptive Mesh Refinement Framework: Design and Magnetohydrodynamic Solvers
• Kilonovae
• Truncated Moment Formalism for Radiation Hydrodynamics in Numerical Relativity
• The Status of Multi-Dimensional Core-Collapse Supernova Models
• Semi-implicit scheme for treating radiation under M1 closure in general relativistic conservative fluid dynamics codes
• Post-merger evolution of a neutron star-black hole binary with neutrino transport
• An Algorithm for Radiation Magnetohydrodynamics Based on Solving the Time-dependent Transfer Equation
• Relativistic Radiation Magnetohydrodynamics in Dynamical Spacetimes: Numerical Methods and Tests
• A New Spherical Harmonics Scheme for Multi-Dimensional Radiation Transport I: Static Matter Configurations
• Numerical Simulations of Optically Thick Accretion onto a Black Hole - II. Rotating Flow
• An Implicit Finite Volume Scheme to Solve the Time Dependent Radiation Transport Equation Based on Discrete Ordinates
• Monte-Carlo closure for moment-based transport schemes in general relativistic radiation hydrodynamics simulations
• Multi-Frequency General Relativistic Radiation-Hydrodynamics with ${\mathbf{M}}_1$ Closure
• Covariant Radiative Transfer for Black Hole Spacetimes
• Radiative MHD Simulations of Photon Bubbles in Radiation-Supported Magnetized Atmospheres of Neutron Stars with Isotropic Thomson Scattering

Cited by in corpus (1)

• General Relativistic Radiation Magnetohydrodynamics Simulations of Precessing Tilted Super-Eddington Disks