Three-dimensional general relativistic radiation magnetohydrodynamical simulation of super-Eddington accretion, using a new code HARMRAD with M1 closure

Jonathan C. McKinney*, Alexander Tchekhovskoy, Aleksander Sadowski, Ramesh Narayan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

230 Scopus citations


Black hole (BH) accretion flows and jets are dynamic hot relativistic magnetized plasma flows whose radiative opacity can significantly affect flow structure and behaviour. We describe a numerical scheme, tests, and an astrophysically relevant application using the M1 radiation closure within a new 3D general relativistic radiation magnetohydrodynamics (GRRMHD) massively parallel code called HARMRAD. Our 3D GRRMHD simulation of super-Eddington accretion (about 20 times Eddington) on to a rapidly rotating BH (dimensionless spin j=0.9375) shows sustained non-axisymmemtric disc turbulence, a persistent electromagnetic jet driven by the Blandford-Znajek effect, a disc wind, and a polar radiation jet. The total accretion efficiency is of the order of 20 per cent, the large-scale electromagnetic jet efficiency is of the order of 10 per cent, the disc wind efficiency is less than 1 per cent, and the total radiative efficiency remains low at only of the order of 1 per cent (of order the Eddington luminosity). However, the radiation jet and the electromagnetic jet both emerge from a geometrically beamed polar region, with super-Eddington isotropic equivalent luminosities. Such simulations with HARMRAD can enlighten the role of BH spin versus discs in launching jets, help determine the origin of spectral and temporal states in X-ray binaries, help to understand how tidal disruption events work, provide an accurate horizon-scale flow structure for M87 and other active galactic nuclei (AGN), and isolate whether AGN feedback is driven by radiation or by an electromagnetic, thermal, or kinetic wind/jet. For example, the low radiative efficiency and weak BH spin-down rate from our simulation suggest that BH growth over cosmological times to billions of solar masses by redshifts of z ~ 6-8 is achievable even with rapidly rotating BHs and 10 M⊙ BH seeds.

Original languageEnglish (US)
Pages (from-to)3177-3208
Number of pages32
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Jun 2014


  • Accretion, accretion discs
  • Black hole physics
  • Gravitation
  • Hydrodynamics
  • MHD
  • Methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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