Three-dimensional general relativistic radiation magnetohydrodynamical simulation of super-Eddington accretion, using a new code HARMRAD with M1 closure
Citation
McKinney, J. C., A. Tchekhovskoy, A. Sadowski, and R. Narayan. 2014. “Three-Dimensional General Relativistic Radiation Magnetohydrodynamical Simulation of Super-Eddington Accretion, Using a New Code HARMRAD with M1 Closure.” Monthly Notices of the Royal Astronomical Society 441 (4) (May 28): 3177–3208. doi:10.1093/mnras/stu762. http://dx.doi.org/10.1093/mnras/stu762.Abstract
Black hole (BH) accretion flows and jets are dynamic hot relativistic magnetized plasma flows whose radiative opacity can significantly affect flow structure and behavior. We describe a numerical scheme, tests, and an astrophysically relevant application using the M1 radiation closure within a new three-dimensional (3D) general relativistic (GR) radiation (R) magnetohydrodynamics (MHD) massively parallel code called HARMRAD. Our 3D GRRMHD simulation of super-Eddington accretion (about 20 times Eddington) onto a rapidly rotating BH (dimensionless spin j = 0.9375) shows sustained non-axisymmemtric disk turbulence, a persistent electromagnetic jet driven by the Blandford-Znajek effect, and a total radiative output consistently near the Eddington rate. The total accretion efficiency is of order 20%, the large-scale electromagnetic jet efficiency is of order 10%, and the total radiative efficiency that reaches large distances remains low at only order 1%. 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 vs. disks in launching jets, help determine the origin of spectral and temporal states in x-ray binaries, help understand how tidal disruption events (TDEs) 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 ten solar mass BH seeds.Other Sources
https://arxiv.org/abs/1312.6127Terms of Use
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