Global Magnetohydrodynamic Simulations of State Transitions in Black Hole Candidates Ryoji Matsumoto...
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Transcript of Global Magnetohydrodynamic Simulations of State Transitions in Black Hole Candidates Ryoji Matsumoto...
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.)
4th International MAXI Workshop Nov. 30 – Dec. 2, 2010
Activities of Black Hole Candidates
Makita and Matsuda
X-ray light curve of Cyg X-1 (Negoro 1995)
Microquasar GRS1915+105
AGN Jets (NGC4261)
SS433 JetMirabel and Rodriguez 1998
Magnetic Activities of Accretion Disks
3Magnetic fields play essential roles in the angular momentum transport which enables the accretion and release of the gravitational energy
Magneto-rotational Instability : MRI
Angular momentum Balbus and Hawley (1991),
Velikhov (1959)
Three-dimensional Global MHD Simulations of Black Hole Accretion Disks
Initial state t=26350 unit time t0=rg/c
Machida and Matsumoto 2003
Outflows from Accretion Disks
6
7
Structure of the Launching Region of the Outflow
Isosurface of vz=0.05c Magnetic field lines and azimuthal magnetic field
Machida and Matsumoto 2008
How a Black Hole Looks Like
State Transitions in Black Hole Candidates
State Transitions Observed in XTE J1752-223
Nakahira et al. 2010 MAXI Science News #17
1/21
Jetejection
Evolution of Outbursts in Hardness-Intensity Diagram
Remillard 2005
Hard state
10 100KeV
Soft state
10 100KeV
Optically thick cold disk
Optically thin hot disk○ XTE J1752-223
Classical Accretion Disk Models give too Low Transition Luminosity
Solid Curves : Thermal Equilibrium Curves (Abramowicz et al. 1995)
Three-Dimensional MHD Simulation including Optically Thin Cooling
Radiative Cooling : Qrad = Qb T1/2
density temperature Toroidal field
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
Cool Down
Optically Thin Hot Disk Supported by Gas Pressure
Radiative Cooling
~ 10
Optically Thin Cool Disk Supported by Magnetic Pressure
< 1
Final state after the onset of the cooling instability depends on the total azimuthal magnetic flux
Thermal Equilibrium Curves including Azimuthal Magnetic Fields
Oda et al. 2009
Evolution of an Accretion Disk
Steady Model ( Oda et al. 2009 )
XTE J1752-223 ( Nakahira et al. 2010)
Development of Next Generation MHD Simulator for Accretion Disks
Simulation Engine
Platform of MHD Simulator : CANS
Simulation Examples
Simulation Analysis
Radiation MHD
Web Page Visualization
Optimization for Parallel Computers
Riemann Solvers
Relativistic MHD
Application to Accretion Disks
Time Variation of RIAF
Hard to Soft State Transition
Evolution of Soft/Slim Disks
Formation of Relativistic Jets
From HD/MHD to Radiation MHD
HD 3D
B
MHD
Radiation MHD
N6×Nstep
+ I (t,x,y,z)
Cost ∝ N3×Nstep
ρ(t,x,y,z), v(t,x,y,z), P(t,x,y,z)
+B(t,x,y,z)
ISolve Radiation Transfer
3D MeshFinite Difference
Flux Limited Diffusion
Basic Equations
00000
0
0
:4
4)ε(∂
ε∂
η
4
)∇(∇)∇(
∂
∂
0)(∂
ρ∂
PvFv
vv
BBvB
FgBB
vvv
v
EcBEt
E
EcBQQpρt
ρt
cρ
πpρ
tρ
ρt
visJ
-
Interaction with radiation
Global Radiation MHD Simulation
Takeuchi, Ohsuga, and Mineshige 2010 SS433
Axisymmetric 2D Radiation MHD Simulation
We are extending this simulation to 3D Radiation MHD
Accretion Disk Dynamos and Quasi-Periodic Oscillations
X-ray Image by HINODE SatelliteButterfly Diagram of Sunspots (NASA)
Optical image of sunspots by HINODE
Quasi-Periodic Oscillations (QPO s ) in Black Hole
Candidates
Pow
er D
ensi
ty
0.1 1 10 1000.01 Hz
GX 339-4
0.1 1 10 1000.01 Hz
XTE J1550-564
McClintock and Remillard 2004
Local 3D MHD Simulation
(Shi, Krolik, and Hirose 2010) 25
Time Variation of Azimuthal Magnetic Fields
White : β =1Black : dln|B|/dz < 0
Quasi periodic reversal in time scale of 10 rotation
How Azimuthal Magnetic Field Reverses ?
Growth of MRI
+1
+2
-1
Buoyant escape of magnetic flux
+2
-1
Buoyant rise
MRI
Parker Instability
QPOs Appear during the Hard-to-Soft Transition
QPOs
Solid Curves : Thermal Equilibrium Curves (Abramowicz et al. 1995)
High temperature(HT) model
Low temperature (LT) model
Formation of an Inner Torus and QPOs for Cool Accretion Flow
Formation of the inner torus is essential for QPOs
Machida and Matsumoto 2008
Low frequency QPO
QPO period is about 10 rotation of the inner torus
Radial Distribution of Oscillation
Model HT Model LT
Machida et al. 2008
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
END
Thank You