Outline

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Outline

• Theoretical and Observational Motivations
• Theory of Stochastic Acceleration
• Particle Acceleration in Low Luminosity AGNs
• Conclusions

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Discovery of Cosmic Rays
Victor Franz Hess 1912
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Discovery of Cosmic Rays
How to accelerate particles? Scattering with
magnetized clouds How to accelerate heavy
ions? Collisionless electromagnetic
processes How to produce a power-law
spectrum? Shock!?
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Theoretical and Observational Motivations

• Problems of the Classical Shock Acceleration
  Model
• Relative Acceleration of Electrons and Protons

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Problems of the Classical Shock Acceleration Model

• Need Very Efficient Scattering
• Turbulence is introduced in the diffusive shock
  acceleration model in a collisionless plasma
• Injection Problem
• Abundance of 3He and Heavy Elements during solar
  flares

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• Abundance of 3He and Heavy Elements during solar
  flares

Reames and Ng 2004
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• Abundance of 3He and Heavy Elements during solar
  flares

Reames and Ng 2004
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Electron-Proton Coupling in Low Luminosity AGNs
De Villiers et al. 2003 ApJ
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Electron-Proton Coupling in Low Luminosity AGNs
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HESS Galactic Survey
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Electrons vs. Protons
Aharonian et al. 2005, 2006
SNR RX J1713.7-3946
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Electrons vs. Protons
?
?
?
Vela X Nebula
Aharonian et al. 2006
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Ongoing Experiments
IceCube Neutrino Experiment
GLAST
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Theory of Stochastic Acceleration

• Generation of Magnetized Turbulence
• Turbulence Cascade Wave-Wave Coupling
• Resonant Wave-Particle Interaction
• Turbulence Damping and Particle Acceleration

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Dispersion Relation and Resonance Condition
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Turbulence Damping and Particle Acceleration
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Particle Acceleration in LLAGNs
De Villiers et al. 2003 ApJ
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TeV Emission from the Direction of Sgr A
Kosack et al. 2004 Whipple
Aharonian et al. 2005, 2006 HESS
Albert et al. 2006 MAGIC
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Electron Acceleration in Disks
Steady-State
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Electron Acceleration in Disks
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Electron Acceleration in Disks
nRT2 constant B2/nTconstant
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Sub-mm Emission from Disks
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Time Dependent Solutions
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Evolution of Mean Energy
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Particle Acceleration in Funnels
gt1.0
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Electron Proton Acceleration In magnetic field
dominated environments
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Spectrum
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M87
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M87
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M87
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M87
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Conclusions
To probe astronomical sources by observations of
their non-thermal emission, one needs to address
the particle acceleration process. In LLAGNs,
magnetic turbulence play roles in electron
heating, cooling and driving the
accretion. Observations and MHD simulations can
test the electron heating and proton acceleration
model.
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Future Projects
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Future Projects
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Future Projects
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Conclusions
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M87