Accelerating Relativistic Jet Models in Blazars

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Accelerating Relativistic Jet Models in Blazars

• J.F. Zhou
• Chen Zheng

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Outline

• Background information
• Accelerating Kinematics in Relativistic Jets
• Linear Circular Constant Acceleration
• Application to 3C273
• Discussion

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Introduction Unified scheme

• Schematic illustration depicting the standard AGN
  paradigm, based on a central accreting BH that is
  surrounded by fast-moving, line- emitting clouds
  and a torus of obscuring matter.

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Introduction AGN paradigm
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Introduction - Blazars

• Blazars is used to describe the most luminous and
  violent active galactic nuclei characterized by
  variable flat spectrum.

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Introduction superluminal
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Introduction - Profiles for 3C273
The presence of the jet at large angular
distances showed that the core is not point like,
but has an interesting geometry.
The core and jet of 3C273
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Introduction - New observation
One recent paper summarizes some new results from
a multi epoch (1990 to 1997) study at high
observing frequencies (15, 22, 43 and 86 GHZ). It
shows that the one sided core-jet of 3C373 breaks
up into multiple VLBI components
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Introduction - Acceleration
The components seem to accelerate as they
separate at apparent superluminal speeds form the
stationary assumed VLBI core.
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Accelerating Kinematics in Relativistic Jets
basic equations
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Accelerating Kinematics in Relativistic Jets -
acceleration

• The equations tell the relation between µob and
  tob if g is known. On the other hand, if we can
  fit the data well with these equations assuming
  some of characteristics of, maybe it could bright
  some important properties of the core.

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Linear Circular Constant

• Here, we assume two simple characteristics, i.e.
  linear and circular acceleration with constant g
  .

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Acceleration - linear

• When g ?ß, there comes to the linear model.

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Linear Circular Constant Acceleration - Circular
The other case is g ? ß with the constant g and
ß, which leads to following equations
nB is a constant unit vector, nß is the unit
vector along the direction of ß, ß? is the
velocity in the perpendicular direction of nB ,T
is the viewing angle
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Application to 3C273 - methods

• The parameter t is eliminated.
• Since it is nonlinear and the data is not very
  huge, we just try the searching method of the
  definite area, which locates in 0.001lt? ltp/2,
  0.001ltßlt1 and 0.001ltklt1.
• The data of the component C13 and C11 have been
  modified as some of the points with the same
  observed time vary very violently and the
  difference between the Y-coordinate are larger
  than the error.
• The up and down error of the parameters could be
  derived by estimating the difference of parameter
  when it is changed independently in the
  confidence contours decided by the chi-squarer.

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Application to 3C273 results(1)
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Application to 3C273 results(2)
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Discussion viewing angle(1)

• The viewing angles of different components vary
  from to 4 degree to 14 degree, which support for
  the jet rotation rather than lateral
  displacements. Helical Kelvin-Helmholtz
  instabilities propagating in the jet sheath would
  mimic such rotation.
• Scientists have applied linear perturbation
  analysis of Kelvin-Helmholtz instability to model
  the observed double helical structure of the jet
  in the quasar 3C273.

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Discussion viewing angle(2)

• Another explanation could be applied to the
  variety of viewing angle, which is, precession.
• In the central 2 mas region, the trajectories
  indicates the precession which could due to the
  binary black hole system.

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Discussion others

• Difference of acceleration ? rotation of the
  field
• Physical mechanism of acceleration
• ? MHD
• Combination of viewing angle and position angle ?
  3D trajectory
• Mass of the core and the components

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END

• Thank you!