2013/11/22 by A. Sadowski, Aleksander Sądowski, R. Narayan +5 · 336 citations
Physics and Astronomy · #Accretion (finance) #Active galactic nucleus #Astrophysical Phenomena and Observations #Astrophysical jet #Astrophysics #Black hole (networking) #Classical mechanics #General relativity #Outflow #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #Radiative flux #Radiative transfer #Rotating black hole #Supermassive black hole #astro-ph.HE
paper · pdf · doi:10.1093/mnras/stt2479
published in Monthly Notices of the Royal Astronomical Society 439(1), 503-520 (Oxford University Press) · 19 pages, 13 figures, submitted to MNRAS
arxiv created 2013/11/22 · openalex publication_date 2014/01/30 · arxiv updated 2014/03/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A new general relativistic radiation magnetohydrodynamical code koral is described, which employs the M1 scheme to close the radiation moment equations. The code has been successfully verified against a number of tests. Axisymmetric simulations of super-critical magnetized accretion on non-rotating (a* = 0.0) and spinning (a* = 0.9) black holes are presented. The accretion rates in the two models are |M≈ 100\rm -200 M\rm Edd|. These first general relativistic simulations of super-critical black hole accretion are potentially relevant to tidal disruption events and hyper-accreting supermassive black holes in the early Universe. Both simulated models are optically and geometrically thick, and have funnels through which energy escapes in the form of relativistic gas, Poynting flux and radiative flux. The jet is significantly more powerful in the a* = 0.9 run. The net energy outflow rate in the two runs correspond to efficiencies of 5 per cent (a* = 0) and 33 per cent (a* = 0.9), as measured with respect to the mass accretion rate at the black hole. These efficiencies agree well with those measured in previous simulations of non-radiative geometrically thick discs. Furthermore, in the a* = 0.9 run, the outflow power appears to originate in the spinning black hole, suggesting that the associated physics is again similar in non-radiative and super-critical accretion flows. While the two simulations are efficient in terms of total energy outflow, both runs are radiatively inefficient. Their luminosities are only ∼1–10LEdd, which corresponds to a radiative efficiency ∼0.1 per cent. Interestingly, most of the radiative luminosity emerges through the funnels where the local radiative flux is highly super-Eddington.