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Global Magnetohydrodynamic Simulations of State Transitions in Black Hole Candidates

4 th International MAXI Workshop Nov. 30 – Dec. 2, 2010. Global Magnetohydrodynamic Simulations of State Transitions in Black Hole Candidates. Ryoji Matsumoto (Chiba Univ.)

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Global Magnetohydrodynamic Simulations of State Transitions in Black Hole Candidates

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  1. 4th International MAXI Workshop Nov. 30 – Dec. 2, 2010 Global Magnetohydrodynamic Simulations of State Transitions in Black Hole Candidates Ryoji Matsumoto (Chiba Univ.) Collaborators: Takayuki Ogawa , Tomohisa Kawashima (Chiba Univ.) Hiroshi Oda (Shanghai Obs.), and Mami Machida (Kyushu Univ.)

  2. Activities of Black Hole Candidates X-ray light curve of Cyg X-1 (Negoro 1995) AGN Jets (NGC4261) Makita and Matsuda Mirabel and Rodriguez 1998 SS433 Jet Microquasar GRS1915+105

  3. Magnetic Activities of Accretion Disks Magnetic fields play essential roles in the angular momentum transport which enables the accretion and release of the gravitational energy

  4. Magneto-rotational Instability：MRI Angular momentum Balbus and Hawley (1991), Velikhov (1959)

  5. Three-dimensional Global MHD Simulations of Black Hole Accretion Disks Initial state t=26350 unit time t0=rg/c Machida and Matsumoto 2003

  6. Outflows from Accretion Disks

  7. Structure of the Launching Region of the Outflow Magnetic field lines and azimuthal magnetic field Isosurface of vz=0.05c Machida and Matsumoto 2008

  8. How a Black Hole Looks Like

  9. State Transitions in Black Hole Candidates

  10. State Transitions Observed in XTE J1752-223 1/21 Jet ejection MAXI Science News #17 Nakahira et al. 2010

  11. Soft state Hard state Evolution of Outbursts in Hardness-Intensity Diagram Remillard 2005 10 100 10 100 KeV KeV Optically thick cold disk Optically thin hot disk ○XTE J1752-223

  12. Classical Accretion Disk Models give too Low Transition Luminosity Solid Curves : Thermal Equilibrium Curves (Abramowicz et al. 1995)

  13. Three-Dimensional MHD Simulation including Optically Thin Cooling Radiative Cooling : Qrad = Qb r 2 T1/2 temperature Toroidal field density Machida et al. 2006, PASJ 58, 193

  14. Time Evolution β=Pgas/Pmag

  15. Formation of a Magnetically Supported Disk Before the transition After the transition Machida, Nakamura and Matsumoto 2006

  16. Schematic Picture of the Growth of the Cooling Instability Radiative Cooling Cool Down b < 1 b ~ 10 Optically Thin Cool Disk Supported by Magnetic Pressure Optically Thin Hot Disk Supported by Gas Pressure Final state after the onset of the cooling instability depends on the total azimuthal magnetic flux

  17. Thermal Equilibrium Curves including Azimuthal Magnetic Fields Oda et al. 2009

  18. Evolution of an Accretion Disk Steady Model （Oda et al. 2009） XTE J1752-223 （Nakahira et al. 2010)

  19. Development of Next Generation MHD Simulator for Accretion Disks Optimization for Parallel Computers Platform of MHD Simulator : CANS Simulation Engine Simulation Examples Simulation Analysis Riemann Solvers Relativistic MHD Radiation MHD Web Page Visualization Application to Accretion Disks Time Variation of RIAF Hard to Soft State Transition Evolution of Soft/Slim Disks Formation of Relativistic Jets

  20. From HD/MHD to Radiation MHD 3D Mesh Finite Difference HD 3D ρ(t,x,y,z), v(t,x,y,z), P(t,x,y,z) Cost ∝N3×Nstep MHD Flux Limited Diffusion +B(t,x,y,z) Ｂ Solve Radiation Transfer Ｉ Radiation MHD + Ｉ(t,x,y,z,n,q,f) N6×Nstep

  21. Basic Equations Interaction with radiation

  22. Global Radiation MHD Simulation SS433 Takeuchi, Ohsuga, and Mineshige 2010 Axisymmetric 2D Radiation MHD Simulation We are extending this simulation to 3D Radiation MHD

  23. Accretion Disk Dynamos and Quasi-Periodic Oscillations Optical image of sunspots by HINODE X-ray Image by HINODE Satellite Butterfly Diagram of Sunspots (NASA)

  24. Power Density 0.01 0.01 0.1 0.1 1 1 10 10 100 100 Hz Hz GX 339-4 Quasi-Periodic Oscillations （ＱＰＯs） in Black Hole Candidates XTE J1550-564 McClintock and Remillard 2004

  25. Local 3D MHD Simulation (Shi, Krolik, and Hirose 2010) White ：β＝１ Black ：　dln|B|/dz < 0 Time Variation of Azimuthal Magnetic Fields Quasi periodic reversal in time scale of 10 rotation

  26. How Azimuthal Magnetic Field Reverses ? MRI ＋１ Growth of MRI ＋２ －１ Parker Instability Buoyant escape of magnetic flux ＋２ Buoyant rise －１

  27. QPOs Appear during the Hard-to-Soft Transition QPOs Solid Curves : Thermal Equilibrium Curves (Abramowicz et al. 1995)

  28. Formation of an Inner Torus and QPOs for Cool Accretion Flow Low frequency QPO Formation of the inner torus is essential for QPOs QPO period is about 10 rotation of the inner torus Low temperature (LT) model High temperature(HT) model Machida and Matsumoto 2008

  29. Radial Distribution of Oscillation Model HT Model LT Machida et al. 2008

  30. Summary • Global 3D MHD simulations enabled us to study the evolution of an accretion disk without assuming the alpha-viscosity • During the hard-to-soft transition, magnetically supported, cool disk is formed. This disk can explain the luminous hard state observed in black hole candidates • Global 3D Radiation MHD simulations will reveal the mechanism of transitions to the soft state • Disk dynamo can generate low frequency QPOs

  31. END Thank You

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