Numerical simulations of super-critical black hole accretion flows in general relativity

By A. Sa̧dowski, Ramesh Narayan, J. McKinney, A. Tchekhovskoy. 2013

261 citations recorded by the source corpus.

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 a non-rotating black hole (a=0.0) and a spinning black hole (a=0.9) are presented. The accretion rates in the two models are \dot M = 100-200 \dot M_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% (a=0) and 33% (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 disks. 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 \sim 1-10 L_Edd, which corresponds to a radiative efficiency \sim 0.1%. Interestingly, most of the radiative luminosity emerges through the funnels, which subtend a very small solid angle. Therefore, measured in terms of a local radiative flux, the emitted radiation is highly super-Eddington.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5a1a9102023a334a4b337873f39162b2c98c4fd6

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Citations in the corpus

The Event Horizon General Relativistic Magnetohydrodynamic Code Comparison Project (2019, methodology): “In fact, a large simulation library comprising 43 well-resolved GRMHD simulations has been created for comparison to the observations, using iharm3D, KORAL, H-AMR, and BHAC (Event Horizon Telescope Collaboration et al. 2019b).”
Titans of the early Universe: The Prato statement on the origin of the first supermassive black holes (2018, background): “Black holes accreting at rates above the Eddington limit have been shown to generate powerful jets (McKinney, Tchekhovskoy, & Blandford 2013; Sa̧dowski et al. 2014, 2016; Jiang et al. 2014) which may significantly disrupt the accretion flow.”
Global simulations of axisymmetric radiative black hole accretion discs in general relativity with a mean-field magnetic dynamo (2014, methodology): “2.1 GRRMHD code — KORAL We use the general relativistic radiation magnetohydrodynamics (GRRMHD) code KORAL (Sa̧dowski et al. 2013a, 2014), which employs a Godunov scheme to evolve the rest mass, energy and momentum conservation equations in a fixed, arbitrary spacetime using finite-difference…”
Cool outflows in galaxies and their implications (2020, unknown): “10−3 (e.g., Sadowski et al. 2013, 2014; Sadowski and Narayan 2015; Jiang et al. 2014; McKinney et al. 2014, 2015).”
Three-dimensional simulations of supercritical black hole accretion discs - luminosities, photon trapping and variability (2015, methodology): “The qualitative properties of the 3D simulations described here agree well with accretion flows simulated in the recent years in axisymmetry e.g., by Sądowski et al. (2014), and in threedimensions by McKinney et al. (2014).”
Super-Eddington Accretion Disks around Supermassive Black Holes (2017, methodology): “…rates are ∼ 25 − 50ṀEdd, these simulations do confirm that the radiative efficiency can reach ∼ 4%− 6% as in Jiang et al. (2014a), although it is still unclear why it is different from the results found by others (McKinney et al. 2014; Sa̧dowski et al. 2014) in the similar accretion rate range.”
A GLOBAL THREE-DIMENSIONAL RADIATION MAGNETO-HYDRODYNAMIC SIMULATION OF SUPER-EDDINGTON ACCRETION DISKS (2014, methodology): “Comparison with Previous Simulations Super-Eddington accretion disks for non-spinning black holes have been studied extensively with 2D axisymmetric radiation hydro or MHD simulations (Ohsuga et al. 2005, 2009; Ohsuga & Mineshige 2011, 2013; Sa̧dowski et al. 2014).”
First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring (2019, unknown): “Saḑowski et al. (2013b; see also Saḑowski et al. 2014, 2017; McKinney et al. 2014) applied the M1 closure (Levermore 1984), which treats the radiation as a relativistic fluid.”