The event horizon general relativistic magnetohydrodynamic code comparison project

The Event Horizon Telescope Collaboration

Research output: Contribution to journalArticlepeer-review


Recent developments in compact object astrophysics, especially the discovery of merging neutron stars by LIGO, the imaging of the black hole in M87 by the Event Horizon Telescope, and high- precision astrometry of the Galactic Center at close to the event horizon scale by the GRAVITY experiment motivate the development of numerical source models that solve the equations of general relativistic magnetohydrodynamics (GRMHD). Here we compare GRMHD solutions for the evolution of a magnetized accretion flow where turbulence is promoted by the magnetorotational instability from a set of nine GRMHD codes: Athena++, BHAC, Cosmos++, ECHO, H-AMR, iharm3D, HARM-Noble, IllinoisGRMHD, and KORAL. Agreement among the codes improves as resolution increases, as measured by a consistently applied, specially developed set of code performance metrics. We conclude that the community of GRMHD codes is mature, capable, and consistent on these test problems.

Original languageEnglish (US)
Article number243
JournalAstrophysical Journal, Supplement Series
Issue number2
StatePublished - 2019


  • Black hole physics
  • Magnetic fields
  • Magnetohydrodynamics (MHD)
  • Methods: numerical
  • Relativistic processes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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