Global Radiation-Magnetohydrodynamic Simulations of Black-Hole Accretion Flow and Outflow: Unified Model of Three States

By K. Ohsuga, S. Mineshige, Masao Mori, Y. Kato. 2009

166 citations recorded by the source corpus.

Black-hole accretion systems are known to possess several distinct modes (or spectral states), such as low/hard state and high/soft state. Since the dynamics of the corresponding flows is distinct, theoretical models were separately considered for each state. We here propose a unified model based on our new, global, two-dimensional radiation-magnetohydrodynamic simulations. By controlling a density normalization we could for the first time reproduce three distinct modes of accretion flow and outflow with one numerical code. When the density is large (model A), a geometrically thick, very luminous disk forms, in which photon trapping takes place. When the density is moderate (model B), the accreting gas can effectively be cooled by emitting radiation, thus generating a thin disk, i.e., a soft-state disk. When the density is too low for radiative cooling to be important (model C), a disk becomes hot, thick, and faint; i.e., a hard-state disk. The magnetic energy is amplified within the disk up to about twice, 30%, and 20% of the gas energy in models A, B, and C, respectively. Notably, the disk outflows with helical magnetic fields, which are driven either by radiation-pressure force or magnetic-pressure force, are ubiquitous in any accretion modes. Finally, our simulations are consistent with the phenomenological ˛-viscosity prescription; that is, the disk viscosity is proportional to the pressure.

Subfields: Astronomy and Astrophysics, Geophysics

View Paper: https://www.semanticscholar.org/paper/b59223e9697e57cffbbfe4fd2af3ffa7ace576b2

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. A. Sa̧dowski
3. A. Tchekhovskoy
4. F. Yuan
5. J. McKinney
6. S. Davis
7. Yucong Zhu
8. James M. Stone

In Geophysics

1. Ramesh Narayan
2. A. Sa̧dowski
3. A. Tchekhovskoy
4. J. McKinney
5. F. Yuan
6. A. Kulkarni
7. S. Davis
8. Yucong Zhu

Citations in the corpus

• DISCOVERY OF ULTRA-FAST OUTFLOWS IN A SAMPLE OF BROAD-LINE RADIO GALAXIES OBSERVED WITH SUZAKU (2010, background): “The estimated location of these UFOs at distances within ∼0.01–0.3 pc from the central super-massive black hole suggests that the outflows might be connected with AGN accretion disk winds/ejecta (e.g., King & Pounds 2003; Proga & Kallman 2004; Ohsuga et al. 2009; King 2010).”
• Hot Accretion Flows Around Black Holes (2014, background): “Ohsuga and collaborators (e.g., Ohsuga et al. 2009, Ohsuga & Mineshige 2011) have carried out simulations with full radiative transfer and have studied a wide range of accretion rates.”
• Hyper-Eddington accretion flows on to massive black holes (2015, background): “…and jets from the inner accretion disk in the vertical direction could potentially break the hyper-Eddington accretion solution (e.g. Begelman 2002; Ohsuga et al. 2005, 2009; Dotan & Shaviv 2011; Li, Ostriker & Sunyaev 2013; Jiang, Stone & Davis 2014; McKinney et al. 2014; Sa̧dowski et al. 2015;…”
• EVIDENCE FOR ULTRA-FAST OUTFLOWS IN RADIO-QUIET ACTIVE GALACTIC NUCLEI. II. DETAILED PHOTOIONIZATION MODELING OF Fe K-SHELL ABSORPTION LINES (2011, background): “…highly ionized absorbing material outflowing from their nuclei, possibly connected with accretion disk winds/ejecta (e.g., King & Pounds 2003; Proga & Kallman 2004; Sim et al. 2008; Ohsuga et al. 2009; King 2010a; Sim et al. 2010) or the base of a possible weak jet (e.g., Ghisellini et al. 2004).”
• GRMHD simulations of magnetized advection‐dominated accretion on a non‐spinning black hole: role of outflows (2012, background): “The latter variety of ADAF is referred to as a ‘slim disc’ (Abramowicz et al. 1988) and requires a radiation MHD code to simulate (see Ohsuga et al. 2009; Ohsuga & Mineshige 2011; and references therein). flow (RIAF).”
• GLOBAL STRUCTURE OF THREE DISTINCT ACCRETION FLOWS AND OUTFLOWS AROUND BLACK HOLES FROM TWO-DIMENSIONAL RADIATION-MAGNETOHYDRODYNAMIC SIMULATIONS (2011, methodology): “In the previous paper (Ohsuga et al. 2009), we investigated the time evolution of the magnetic torque of z < ∼ 3RS, and demonstrated that the torque is roughly proportional to the total pressure but with some scatters.”
• Evidence for ultra-fast outflows in radio-quiet AGNs - I. Detection and statistical incidence of Fe K-shell absorption lines (2010, background): “Detailed theoretical studies of accretion disk winds in AGNs showed that the inner regions of the outflowing material can be highly ionized by the intense nuclear radiation and can have large outflow velocities (e.g., King & Pounds 2003; Proga & Kallman 2004; Ohsuga et al. 2009; King 2010).”
• Global simulations of axisymmetric radiative black hole accretion discs in general relativity with a mean-field magnetic dynamo (2014, background): “The most common approach in the past was to invoke flux limited diffusion (FLD) (e.g., Hirose et al. 2009b; Blaes et al. 2011; Ohsuga et al. 2009; Ohsuga & Mineshige 2011), which assumes that the radiative flux follows the gradient of the radiative energy density.”
• Numerical simulations of super-critical black hole accretion flows in general relativity (2013, methodology): “Our results for a non-rotating BH are in qualitative agreement with models A in Ohsuga et al. (2009) and Ohsuga & Mineshige (2011), which were simulated using a non-relativistic MHD code with flux-limited diffusion.”
• Semi-implicit scheme for treating radiation under M1 closure in general relativistic conservative fluid dynamics codes (2012, methodology): “…Blaes, Hirose & Krolik 2007; Krolik, Hirose & Blaes 2007; Hirose, Blaes & Krolik 2009a; Hirose, Krolik & Blaes 2009b; Blaes et al. 2011), and even a few full disc simulations have been done with a non-relativistic code using flux-limited diffusion (Ohsuga et al. 2009; Ohsuga & Mineshige 2011).”
• 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).”
• Three-dimensional simulations of supercritical black hole accretion discs - luminosities, photon trapping and variability (2015, methodology): “The pioneering initial work was based on Newtonian codes with crude (flux-limited diffusion) radiative transport (Ohsuga et al. 2009; Ohsuga & Mineshige 2011).”
• Unification of X-ray winds in Seyfert galaxies: from ultra-fast outflows to warm absorbers (2012, background): “Some attempts in this direction have been reported in the literature (Proga 2000, 2003; Everett 2005; Ohsuga et al. 2009; Reynolds 2012).”