Astrophysical Jets

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Astrophysical Jets
Robert Laing (ESO)
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Jets are everywhere
Gamma-ray burst
Young stellar object
Galactic black-hole binary system
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Jets in Active Galaxies
with an emphasis on the nearby Well-collimated,
bulk relativistic flows with G gt 5 Powered by
accretion onto black holes M ?106 - 1010
MSUN Powers can be as high as 1041 W Major
effects on galaxy formation and cluster
evolution Efficient accelerators electrons 1014
eV ? protons gt1020 eV

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Jets in radio galaxies up to Mpc scales
FRI low power Deceleration Morphological Classi
fication Correlates with radio luminosity FRII
high power Relativistic and supersonic
until hot-spots
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Key topics

• Where are the emission sites? What are the
  radiation mechanisms?
• Jet velocity fields
• Effects on galaxy formation and cluster evolution
• Composition, power thrust
• Formation and collimation mechanism

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Emission from jets broad-band and on many scales
Auger
Radio - TeV Gamma ray Synchrotron and
inverse Compton ? broad electron
energy distribution B Protons?

Cen A - X-ray synchrotron
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Relativistic effects in jets
Energy spectrum
Doppler boosting
Doppler factor
Jet/counter-jet ratio
Aberration
Superluminal motion
Blazars (? ? 0) are bright, and
rapidly-varying Low-power radio galaxies
are side-on TeV blazars
vapp 30c
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M87 TeV - core or HST-1

Look for correlated variability with both core
and HST-1
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Jet velocity fields
Kovalev et al. 2007

Limb-brightening and slow component speeds
gradual acceleration or fast spine slow shear
layer?
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Acceleration ? deceleration?
Hardcastle et al. 2003
NGC315

Tingay et al.
Cotton et al. 1999 RL et al. 2006
TeV results require very high G - where are
jets accelerated?
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Velocity fields on large scales
VLA data ? 58o Model

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Velocity ß v/c deceleration and transverse
gradients
NGC 315
3C296

B2 032639
3C 31
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Environmental Impact
shock
1061 erg
380 kpc
Wise et al. 07
Hydra A
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Low Radio Frequency Traces Energy
Feedback from jets halts cooling in cores of
galaxy clusters Quenching of star formation ?
major influence on galaxy formation (downsizing)
Radio Lane et al. 04/Taylor
Wise et al. 07
74 MHz
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Composition?

• Electromagnetic
• Leptonic (pair plasma) - not near black hole
• Hadronic (electron-proton plasma relativistic
  protons?)
• Composition must change along the jet.
• EM ? particles
• Entrainment of external medium
• Faraday rotation?
• Bulk Comptonization
• Mass, energy, momentum budget

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Sunyaev-Zeldovich Effect and Radio Lobe
Composition

Perseus cluster (NGC1275/3C84) Contours
radio Colour X-ray Extra pressure component
Simulation of ALMA observation of SZ
decrement in Perseus cluster
Bubble profiles for different lobe compositions
Pfrommer, Ensslin Sarazin (2005)
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Pressure and density
3C31 032639
3C296
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Mach number and entrainment rate
Stars
Jets must be very light consistent with
electron-positron plasma
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Power estimates from cavities

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M87 86GHz
174 Rs
Limits on collimation from mm VLBI Jet base 70 x
20 RS
Krichbaum et al. 2006
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Magnetic collimation?

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Coming shortly .... we hope
eMERLIN
EVLA
LWA, eLOFAR
VSOP-2
GLAST
ALMA