DIRECT CALCULATION OF THE RADIATIVE EFFICIENCY OF AN ACCRETION DISK AROUND A BLACK HOLE

By Scott Noble, Julian Krolik, J. Hawley. 2008

133 citations recorded by the source corpus.

Numerical simulation of magnetohydrodynamic (MHD) turbulence makes it possible to study accretion dynamics in detail. However, special effort is required to connect inflow dynamics (dependent largely on angular momentum transport) to radiation (dependent largely on thermodynamics and photon diffusion). To this end, we extend the flux-conservative, general relativistic MHD (GRMHD) code HARM from axisymmetry to full three dimensions. The use of an energy conserving algorithm allows the energy dissipated in the course of relativistic accretion to be captured as heat. The inclusion of a simple optically thin cooling function permits explicit control of the simulated disk's geometric thickness as well as a direct calculation of both the amplitude and location of the radiative cooling associated with the accretion stresses. Fully relativistic ray-tracing is used to compute the luminosity received by distant observers. For a disk with aspect ratio H/r ≃ 0.1 accreting onto a black hole with spin parameter a/M = 0.9, we find that there is significant dissipation beyond that predicted by the classical Novikov–Thorne model. However, much of it occurs deep in the potential, where photon capture and gravitational redshifting can strongly limit the net photon energy escaping to infinity. In addition, with these parameters and this radiation model, significant thermal and magnetic energy remains with the gas and is accreted by the black hole. In our model, the net luminosity reaching infinity is 6% greater than the Novikov–Thorne prediction. If the accreted thermal energy were wholly radiated, the total luminosity of the accretion flow would be ≃20% greater than the Novikov–Thorne value.

Subfields: Astronomy and Astrophysics, Geophysics, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/9c1be321f10183a5c4483d6683c841797d6edfe6

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. Ramesh Narayan
2. J. McKinney
3. A. Tchekhovskoy
4. A. Sa̧dowski
5. J. E. McClintock
6. F. Yuan
7. J. Dexter
8. J. Steiner

In Geophysics

1. Ramesh Narayan
2. J. McKinney
3. J. E. McClintock
4. A. Tchekhovskoy
5. Ronald A. Remillard
6. J. Steiner
7. A. Sa̧dowski
8. Scott Noble

In Mechanical Engineering

1. J. Hawley
2. A. Sa̧dowski
3. D. M. Alexander
4. J. E. McClintock
5. W. N. Brandt
6. Lijun Gou
7. J. Steiner
8. E. Agol

Citations in the corpus

• THE SUBMILLIMETER BUMP IN Sgr A* FROM RELATIVISTIC MHD SIMULATIONS (2010, background): “However, few energy conserving three dimensional GRMHD simulations have been run to date (Shafee et al. 2008; Noble et al. 2009; Noble & Krolik 2009; McKinney & Blandford 2009; Noble et al. 2010).”
• Cosmic X-ray surveys of distant active galaxies (2015, background): “1 as high as ≈ 3.6 (e.g., Agol and Krolik 2000; Noble et al 2009, 2011; J.H. Krolik 2014, private communication).”
• GENERAL RELATIVISTIC HYDRODYNAMIC SIMULATION OF ACCRETION FLOW FROM A STELLAR TIDAL DISRUPTION (2015, methodology): “We use the fully conservative general relativistic magnetohydrodynamics code HARM3D for our global simulation (Gammie et al. 2003; Noble et al. 2009); there is, however, no magnetic field in the simulation reported here.”
• CO-EVOLUTION OF GALACTIC NUCLEI AND GLOBULAR CLUSTER SYSTEMS (2013, background): “In case of the maximum radiative efficiency for a rotating black hole,ǫ ≈ 0.3− 0.4 (Thorne 1974; Noble et al. 2009), the timescale is 4–6 times longer.”
• ASSESSING QUANTITATIVE RESULTS IN ACCRETION SIMULATIONS: FROM LOCAL TO GLOBAL (2011, background): “…from pseudo-Newtonian dynamics (Hawley & Krolik 2001; Machida & Matsumoto 2003) to full three-dimensional general relativistic physics (De Villiers & Hawley 2003; Gammie et al. 2003; Anninos et al. 2005), most recently including toy-model thermodynamics (Noble et al. 2009; Shafee et al. 2008).”
• The Masses and Spins of Neutron Stars and Stellar-Mass Black Holes (2014, background): “Thus the shape of this cutoff and exactly how it is positioned with respect to the ISCO introduce a certain amount of systematic uncertainty in the spin determination [266, 267, 261].”
• Three-dimensional general relativistic radiation magnetohydrodynamical simulation of super-Eddington accretion, using a new code HARMRAD with M1 closure (2013, background): “Simulations have only so-far included an ad hoc cooling function that leads to |H/R| ∼ 0.05–0.1 (Shafee et al. 2008; Reynolds & Fabian 2008; Reynolds & Miller 2009; Noble et al. 2009; Penna et al. 2010; Noble et al. 2010; Sorathia et al. 2010; Noble et al. 2011b; Beckwith et al. 2011).”
• General relativistic magnetohydrodynamic simulations of magnetically choked accretion flows around black holes (2012, unknown): “Simulations have studied |H/R| ∼ 0.05–0.1 (Shafee et al. 2008; Reynolds & Miller 2009; Noble et al. 2009, 2010; Sorathia et al. 2010; Beckwith et al. 2011), |H/R| ∼ 0.1–0.15 (De Villiers et al. 2003; Beckwith et al. 2008b,a, 2009), |H/R| ∼ 0.2 (Hawley & Balbus 2002; Machida et al. 2000; Machida &…”
• THE CONSTANT INNER-DISK RADIUS OF LMC X-3: A BASIS FOR MEASURING BLACK HOLE SPIN (2010, background): “…the inner-disk radius Rin with the radius of the innermost stable circular orbit RISCO (Reynolds & Fabian 2008; Shafee et al. 2008; Penna et al. 2010; but see Noble et al. 2009), a proposition that has a long history of theoretical and observational support (e.g., see Section 6 in Gou et al. 2009).”