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

166 Scopus citations

Abstract

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
Volume441
Issue number4
DOIs
StatePublished - Jun 2014

Keywords

  • 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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