# Presentation: 008383

## Gamma Rays from Accreting Black Holes

- Roger Blandford
- KIPAC, Stanford

- GLAST GC Meeting

- 1 ix 05

## Accretors

- Protostars
- Planets
- Cataclysmic Variables
- X-ray Binaries
- Disk Galaxies!
- Active Galactic Nuclei
- Inactive Galactic Nuclei
- Gamma Ray Bursts**?**
- ...

- GLAST GC Meeting

- 1 ix 05

## Traditional Disks are:

- Conservative
- Stationary
- Radiative
- Thin
- Fluid dynamical

- GLAST GC Meeting

- 1 ix 05

## Traditional Disk Power

**Traditional Disk Power**

**Angular Momentum**
**Energy**

**Keplerian Disk**

**Dissipation**

- rout

- rin

**Torque**

**Binding**
**Energy**

- GLAST GC Meeting

- 1 ix 05

## Outflows,winds, jets remove, mass, angular momentum, energy
Thick (H~r/M)
Ion pressure 
Dissipated energy heats ions
Poor ion-electron coupling
Cold electrons don’t radiate
Radio galaxies
Radiation pressure 
Thomson scattering optical depth
Photons trapped within
Advected inwards   
BALQs

- Thick (H~r/M)
- Ion pressure
- Dissipated energy heats ions
- Poor ion-electron coupling
- Cold electrons don’t radiate
- Radio galaxies
- Radiation pressure
- Thomson scattering optical depth
- Photons trapped within
- Advected inwards
- BALQs

**Non-conservative disks**

- GLAST GC Meeting

- 1 ix 05

## Torque Transports Energy

**Torque Transports Energy**

- Angular Momentum Transport

- Energy Transport

- Bernoulli Function

- Energy transport from small r
- by torque unbinds gas at large r.

- GLAST GC Meeting

- 1 ix 05

## ADAF vs ADIOS

**ADAF**** vs ****ADIOS**

- Advection-Dominated Accretion Flow
- Liberated binding energy advected across horizon
- ADiabatic Inflow-Outflow Solution
- Liberated binding energy carried off in a wind
- Removes mass, angular momentum and energy
- Mass accretion<<mass supply
- Hydromagnetic for low mass supply rate
- Radiatively driven for high mass supply rate?
**Accretion** efficiency always high ~ 0.1c2

*RB & Begelman*
*1999, 2004*

*Quataert*

**These are radically different and distinguishable**

- GLAST GC Meeting

- 1 ix 05

## Self-Similar, Fluid, Disk-Wind Model

- Disk
- Bound
- Gyrentropic
- Circulation
- Inflow
- Wind
- Thermal Front
- Unbound
- Jet
- Evacuated cone

*RB & Begelman*

- GLAST GC Meeting

- 1 ix 05

## Sketch Disk Model

- Radio spectrum S ~ 1/3, <1THz
-  T~1011(/1cm)5/3(r/6m)-2K
- Optically thin at all radii for <1cm
- Superpose radiation from a range of radii
- Polarization (Broderick+B)
- X-ray emission from synchrotron radiation from high energy tail (cf Liu)
- Jet emission model also possible (Falcke)

- GLAST GC Meeting

- 1 ix 05

## Sketch Disk Model

- (dM/dt)sup~1021-22 g/s
- (dM/dt)acc~1018-19 g/s
- Power release ~1038-39 erg/s
- Luminosity ~ 1036 erg/s => wind
- eg 1021 g/s at 5000km/s
- Shocks at ~ (V/cs)1/2 rB ~ 1 lt yr (cf Atoyan)
- Could be competitive with colliding stellar winds
- Particle acceleration site for H.E.S.S., GLAST photons?
- 10TeV photons must originate outside10m

- GLAST GC Meeting

- 1 ix 05

## Real Disks are Magentized

- Magnetorotational Instability

*Hawley et al*

- GLAST GC Meeting

- 1 ix 05

## Jet/Outflow Formation

- Gas dynamics flows
- Hadronic jets
- Hydromagnetic wind launched from disk
- Toroidal flux loops
- Poloidal channels
- Centrifugally-driven
- Electromagnetic-power from spinning hole
- Collimated by disk wind
- Hybrid Models

- GLAST GC Meeting

- 1 ix 05

## Energy Extraction from Spinning Hole

- Electromagnetic extraction of energy from hole
- Causal?
- Efficient?

*Krasnopolsky*

*Also Gammie, Komissarov, Hawley, Koide et al*

- GLAST GC Meeting

- 1 ix 05

## 

Rules of thumb: 
 B R2 ; V ~  
I~ V /  Z0;  P ~ V I
               PWN           AGN       GRB  
B            100 MT     1 T          1 TT  
             10 Hz        10 Hz   1 kHz
R            10 km       10 Tm     10 km
V            3 PV         300 EV    30 ZV     
I             300 TA     3 EA        300 EA
P             100 XW   1 TXW    10 PXW

- Rules of thumb:
-  B R2 ; V ~ 
- I~ V /  Z0;  P ~ V I
-                **PWN           AGN       GRB**
**B**** **           **100 MT     1 T          1 TT**
******             ****10 Hz        10 ********Hz   1 kHz**
**R****            10 km       10 Tm     10 km**
**V ****           3 PV         300 EV    30 ZV     **
**I****             300 TA     3 EA        300 EA**
**P****             100 XW   1 TXW    10 PXW**

*Unipolar Induction*

- UHECR!

- GLAST GC Meeting

- 1 ix 05

## Simulations are transforming our understanding of disks

- MHD
- 3D
- GR
- Plot of magnetic energy density

*Villiers et al*

- GLAST GC Meeting

- 1 ix 05

## More Variations

- Energy transport
- AC transmission (eg Spruit, Thompson)
- eg chaotic electromagnetic fields with length scale         ~ 100-1000 km, characteristic of the source variation
*E~B as relativistic *
- Dynamically like radiation-dominated outflow
*Scalar pressure*
*No active collimation*
- Natural particle acceleration mechanisms

- GLAST GC Meeting

- 1 ix 05

## More Variations

- Energy Transport
- Local DC transmission
- Episodic ejection of magnetically-confined jet segments
- No large scale current circuits
- Relativistic motion
- Changing polarity of parallel field reflects changing polarity of disk field
- Disk may eject loops of toroidal field or be launched and collimated by vertical field

- GLAST GC Meeting

- 1 ix 05

## More Variations

- Energy transport
- Global DC transmission
- Large scale order in magnetic field
- Large scale current circuits
- Toroidal magnetic field dominates parallel field far from the source
*If flux is conserved, parallel field ~ (Area)**-1*
*If current conserved toroidal field ~ (Area)**-1/2*
- E~B still and energy carried by Poynting flux ~ B2c
*Center of momentum frame moves relativistically*
- Need equipartition particle pressure along axis to oppose hoop stress of toroidal field in comoving frame.

- GLAST GC Meeting

- 1 ix 05

## Pictor A

**Magnetic Pinch?**

- GLAST GC Meeting

- 1 ix 05

## Pictor A

**Current Flow**

**Nonthermal emission **
**is ohmic dissipation **
**of current flow? **

- Electromagnetic Transport
- 1018 not 1017 A
- DC not AC
- No internal shocks
- New particle acceleration mechanisms

**Pinch stabilized by **
**velocity gradient **
**Equipartition in core**

*Wilson et al*

- GLAST GC Meeting

- 1 ix 05

## IGN

- Sgr A* Jet?
- ~3PV
- I~300TA
- LEM~1030W
- Lwind 1032W

- Baganoff, Morris etal

- Llobe  ~ 1032 W?

- GLAST GC Meeting

- 1 ix 05

## Archimedean Disks

- rout ~ (c/vout)2rin ~106rin.

*RB, Wang et al*

- GLAST GC Meeting

- 1 ix 05

## Archimedean Disks

- rout ~ (c/vout)2rin ~106rin.

- GLAST GC Meeting

- 1 ix 05

## Archimedean Disks

**Archimedean Disks**

- rout ~ (c/vout)2rin ~106rin.

- Net radial field
- Conservative disk
- Ignore irradiation,
- self-gravitation etc

**Magnetic pressure dominates and field lines escape**

- GLAST GC Meeting

- 1 ix 05

## Twister

**Twister**

- Mean field configuration is MRI unstable.
- Growth time ~ Period
-   H
**Conjecture**
- Mean field is responsible for the torque
- Random component is responsible for effective
-          resistivity and viscosity

**Test with numerical simulations**

- GLAST GC Meeting

- 1 ix 05

## Inner Disk - Black Holes

**Inner Disk - Black Holes**

- 

******B>**

- J

**.**

- GLAST GC Meeting

- 1 ix 05

## Asymmetric Outflows/Jets

**X**

**Can you measure the toroidal field pattern?**

**Even Parity**

**Odd Parity**

**Mixed Parity**

- GLAST GC Meeting

- 1 ix 05

## Quasars for the Impatient

**Quasars for the Impatient**

- Intensity / Eddington

- <10-6

- ~0.01

- ~0.1

- ~1.0

- soft
- spectrum

- hard
- spectrum

- Quiescence

*Fender*

- GLAST GC Meeting

- 1 ix 05

## Jet Fuel

**Jet Fuel**

- Relativistic Jets Powered by Black Hole Spin
- Thick disks spin down hole electromagnetically
- Thin disks spin up hole through accretion

- 10

- 1

- 0.1

- Thick Ion Disk
- Spin Down, Steady,
- Radio Loud

- Thin Radiative Disk
- Spin Up
- Radio Quiet

- Thick Radiation Disk
- Spin Up/Down
- Unsteady

- Jet properties depend
- upon mass supply rate
- and history.

- GLAST GC Meeting

- 1 ix 05

## Jet Fuel

**Jet Fuel**

- Relativistic Jets Powered by Black Hole Spin
- Thick disks spin down hole electromagnetically
- Thin disks spin up hole through accretion

- 10

- 1

- 0.1

- Jet properties depend
- upon mass supply rate
- and history.

*Width ~****M*

- GLAST GC Meeting

- 1 ix 05

## Summary

- Sgr A* disk may drive large outflow contributing to bipolar lobes and X-ray jet
- Reasonable interpretations of disk spectrum
- TeV emission does not come from Sgr A* hole
- GLAST observations may help us understand IGN like Sgr A*
- Blazar GeV emission comes from relativistic jets
- GLAST observations should diagnose the jet composition and dynamics

- GLAST GC Meeting

- 1 ix 05