A Survey of General Relativistic Magnetohydrodynamic Models for Black Hole Accretion Systems

General relativistic magnetohydrodynamics (GRMHD) simulations are an indispensable tool in studying accretion onto compact objects. The Event Horizon Telescope (EHT) frequently uses libraries of ideal GRMHD simulations to interpret polarimetric, event-horizon-scale observations of supermassive black...

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Main Authors: Vedant Dhruv, Ben Prather, George N. Wong, Charles F. Gammie
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Supplement Series
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Online Access:https://doi.org/10.3847/1538-4365/adaea6
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author Vedant Dhruv
Ben Prather
George N. Wong
Charles F. Gammie
author_facet Vedant Dhruv
Ben Prather
George N. Wong
Charles F. Gammie
author_sort Vedant Dhruv
collection DOAJ
description General relativistic magnetohydrodynamics (GRMHD) simulations are an indispensable tool in studying accretion onto compact objects. The Event Horizon Telescope (EHT) frequently uses libraries of ideal GRMHD simulations to interpret polarimetric, event-horizon-scale observations of supermassive black holes at the centers of galaxies. In this work, we present a library of 10 nonradiative, ideal GRMHD simulations that were utilized by the EHT Collaboration in their analysis of Sagittarius A*. The parameter survey explores both low (SANE) and high (MAD) magnetization states across five black hole spins a _*  = −15/16, −1/2, 0, +1/2, +15/16 where each simulation was run out to 30,000 GM / c ^−3 . We find the angular momentum and energy flux in SANE simulations closely matches the thin-disk value, with minor deviations in prograde models due to fluid forces. This leads to spin equilibrium around a _*  ∼ 0.94, consistent with previous studies. We study the flow of conserved quantities in our simulations and find mass, angular momentum, and energy transport in SANE accretion flows to be primarily inward and fluid dominated. MAD models produce powerful jets with outflow efficiency >1 for a _*  = + 0.94, leading to black hole spin-down in prograde cases. We observe outward directed energy and angular momentum fluxes on the horizon, as expected for the Blandford–Znajek mechanism. MAD accretion flows are sub-Keplerian and exhibit greater variability than their SANE counterpart. They are also hotter than SANE disks within r  ≲ 10 GM / c ^−2 . This study is accompanied by a public release of simulation data at http://thz.astro.illinois.edu/ .
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spelling doaj-art-fb1239dd99bf4a0d84c0385e4703a3592025-08-20T03:13:15ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492025-01-0127711610.3847/1538-4365/adaea6A Survey of General Relativistic Magnetohydrodynamic Models for Black Hole Accretion SystemsVedant Dhruv0https://orcid.org/0000-0001-6765-877XBen Prather1https://orcid.org/0000-0002-0393-7734George N. Wong2https://orcid.org/0000-0001-6952-2147Charles F. Gammie3https://orcid.org/0000-0001-7451-8935Department of Physics, University of Illinois , 1110 West Green Street, Urbana, IL 61801, USA ; vdhruv2@illinois.edu; Illinois Center for Advanced Study of the Universe , 1110 West Green Street, Urbana, IL 61801, USACCS-2 , Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USASchool of Natural Sciences , Institute for Advanced Study, 1 Einstein Drive, Princeton, NJ 08540, USA; Princeton Gravity Initiative, Princeton University , Princeton, NJ 08544, USADepartment of Physics, University of Illinois , 1110 West Green Street, Urbana, IL 61801, USA ; vdhruv2@illinois.edu; Illinois Center for Advanced Study of the Universe , 1110 West Green Street, Urbana, IL 61801, USA; Department of Astronomy, University of Illinois , 1002 West Green Street, Urbana, IL 61801, USAGeneral relativistic magnetohydrodynamics (GRMHD) simulations are an indispensable tool in studying accretion onto compact objects. The Event Horizon Telescope (EHT) frequently uses libraries of ideal GRMHD simulations to interpret polarimetric, event-horizon-scale observations of supermassive black holes at the centers of galaxies. In this work, we present a library of 10 nonradiative, ideal GRMHD simulations that were utilized by the EHT Collaboration in their analysis of Sagittarius A*. The parameter survey explores both low (SANE) and high (MAD) magnetization states across five black hole spins a _*  = −15/16, −1/2, 0, +1/2, +15/16 where each simulation was run out to 30,000 GM / c ^−3 . We find the angular momentum and energy flux in SANE simulations closely matches the thin-disk value, with minor deviations in prograde models due to fluid forces. This leads to spin equilibrium around a _*  ∼ 0.94, consistent with previous studies. We study the flow of conserved quantities in our simulations and find mass, angular momentum, and energy transport in SANE accretion flows to be primarily inward and fluid dominated. MAD models produce powerful jets with outflow efficiency >1 for a _*  = + 0.94, leading to black hole spin-down in prograde cases. We observe outward directed energy and angular momentum fluxes on the horizon, as expected for the Blandford–Znajek mechanism. MAD accretion flows are sub-Keplerian and exhibit greater variability than their SANE counterpart. They are also hotter than SANE disks within r  ≲ 10 GM / c ^−2 . This study is accompanied by a public release of simulation data at http://thz.astro.illinois.edu/ .https://doi.org/10.3847/1538-4365/adaea6AccretionSupermassive black holesLow-luminosity active galactic nucleiMagnetohydrodynamical simulationsRelativistic fluid dynamics
spellingShingle Vedant Dhruv
Ben Prather
George N. Wong
Charles F. Gammie
A Survey of General Relativistic Magnetohydrodynamic Models for Black Hole Accretion Systems
The Astrophysical Journal Supplement Series
Accretion
Supermassive black holes
Low-luminosity active galactic nuclei
Magnetohydrodynamical simulations
Relativistic fluid dynamics
title A Survey of General Relativistic Magnetohydrodynamic Models for Black Hole Accretion Systems
title_full A Survey of General Relativistic Magnetohydrodynamic Models for Black Hole Accretion Systems
title_fullStr A Survey of General Relativistic Magnetohydrodynamic Models for Black Hole Accretion Systems
title_full_unstemmed A Survey of General Relativistic Magnetohydrodynamic Models for Black Hole Accretion Systems
title_short A Survey of General Relativistic Magnetohydrodynamic Models for Black Hole Accretion Systems
title_sort survey of general relativistic magnetohydrodynamic models for black hole accretion systems
topic Accretion
Supermassive black holes
Low-luminosity active galactic nuclei
Magnetohydrodynamical simulations
Relativistic fluid dynamics
url https://doi.org/10.3847/1538-4365/adaea6
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