@article{2dae0a41efbd4d8a9a4126e26db15fbe,
title = "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.",
author = "White, {Christopher J.} and Mullen, {Patrick D.} and Jiang, {Yan Fei} and Davis, {Shane W.} and Stone, {James M.} and Viktoriya Morozova and Lizhong Zhang",
note = "Funding Information: This work made use of the following computing resources: the Extreme Science and Engineering Discovery Environment (XSEDE) cluster Stampede2 at the Texas Advanced Computing Center (TACC), through allocation AST200005; the Oak Ridge Leadership Computing Facility cluster Crusher at the Oak Ridge National Laboratory, supported by the Office of Science of the U. S. Department of Energy; the Argonne Leadership Computing Facility cluster Polaris at Argonne National Laboratory, supported by the Office of Science of the U. S. Department of Energy; the clusters Rusty and Popeye , supported by the Scientific Computing Core at the Flatiron Institute, a division of the Simons Foundation; and the Princeton Research Computing cluster Stellar , managed and supported by the Princeton Institute for Computational Science and Engineering (PICSciE) and the Office of Information Technology{\textquoteright}s High Performance Computing Center and Visualization Laboratory at Princeton University. Funding Information: The authors acknowledge support from NASA TCAN grant 80NSSC21K0496, and S.W.D. acknowledges support from NASA ATP grant 80NSSC18K1018. Publisher Copyright: {\textcopyright} 2023. The Author(s). Published by the American Astronomical Society.",
year = "2023",
month = jun,
day = "1",
doi = "10.3847/1538-4357/acc8cf",
language = "English (US)",
volume = "949",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2",
}