Numerical Simulations of Optically Thick Accretion onto a Black Hole. II. Rotating Flow

Aug 19, 2014
18 pages
Published in:
  • Astrophys.J. 796 (2014) 1, 22
  • Published: Oct 30, 2014
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Abstract: (IOP)
In this paper, we report on recent upgrades to our general relativistic radiation magnetohydrodynamics code, Cosmos++, including the development of a new primitive inversion scheme and a hybrid implicit-explicit solver with a more general M (1) closure relation for the radiation equations. The new hybrid solver helps stabilize the treatment of the radiation source terms, while the new closure allows for a much broader range of optical depths to be considered. These changes allow us to expand by orders of magnitude the range of temperatures, opacities, and mass accretion rates, and move a step closer toward our goal of performing global simulations of radiation-pressure-dominated black hole accretion disks. In this work, we test and validate the new method against an array of problems. We also demonstrate its ability to handle super-Eddington, quasi-spherical accretion. Even with just a single proof-of-principle simulation, we already see tantalizing hints of the interesting phenomenology associated with the coupling of radiation and gas in super-Eddington accretion flows.
Note:
  • 18 pages, 9 figures
  • radiative transfer
  • methods: numerical
  • magnetohydrodynamics
  • black hole physics
  • accretion, accretion disks