Analysis of strong outbursts in selected blazars.

1
Analysis of strong outbursts in selected blazars.

• Pyatunina T.B., Kudryavtseva N.A., Gabuzda D.C.,
  Jorstad S.G., Aller M.F., Aller H.D., Terasranta
  H.

2
Two types of outbursts(Pyatunina et al., 2000,
AA, 358,451 Zhou et al. 2000, ApJ, 540, L13)

• Core outbursts
• show frequency-dependent time-delays
• are associated with cores brightening due to
  primary perturbation.
• Jet outbursts
• arise nearly simultaneously at all frequencies
• are connected with structure evolution due to
  propagation of the perturbation down the jet.

3
What can be found?

• Frequency dependent time lags can be used for
  testing models of non-thermal emission
• (Lobanov, 1998, AA, 330, 79 Marscher 2001,
  ASP Conf.Ser.,224, 23)
• Interval between two subsequent core outbursts
  defines a time scale of activity cycle as a
  whole (from origin primary perturbation to its
  drowing in quiescent jet).

4
Monitoring Data

• Radio Astronomical Observatory of the Michigan
  University, USA
• (Aller H.D., Aller M.F., Latimer G.E., Hodge
  P.E. 1985, ApJS 59,513)
• Metsahovi Radio Observatory, Finland
• (Terasranta H., et al. 1992, AAS, 94, 121)

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0458-020 A core outburst B and C jet
outbursts. Activity time scale 15 yr.
A?
B ?
C ?
? - 37 GHz ? - 22 GHz ? - 14.5 GHz ? - 8 GHz ? -
4.8 GHz
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0528134 Total duration of activity cycle may be
14 yr (1976-1990 1990-2004).
The period (1976-1990) can be classified as a
period of high core activity due to ejection of
several new components and the core flux density
variations (Britzen et al. 1999,AA, 341,
418). Next period of high activity (1990-2004)
reveals numerous narrow outbursts, or rather
spikes in some composite event as spectral
evolution testifies (Pyatunina et al. in prep.)
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0528134The spikes D,E and F show convincing
time-lags and are classified as core
outbursts. Higher frequency data are necessary
for determination of time-lags for spikes A,B
and C, as can be seen from evolution of their
spectra (Pyatunina et al. in prep. ).
8
1730-130, NRAO 530Extremely narrow feature has
been observed in 1995 at 230 GHz (Bower et al.
1997, ApJ, 484, 118, brown ). The fine structure
is unresolved at lower frequency and time-lags
are determined for the outburst as a whole.
Core outburst
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2230114, CTA 102 Three periods of activity with
maxima near 1981, 1989 and 1997 are seen in the
light curves of the source. Emission during
active state consists of a sequence of narrow
outbursts or rather spikes of variable
amplitude.
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2230114Quasi-periodicity at mm- (left) and
cm-wavelengths (right).Spikes A and B show
frequency-dependent time-lags and can be
classified as core outbursts. Spikes C and D are
unresolved at cm-wavelength and their time-lags
are uncertain.
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2230114Correlation between amplitudes of
outbursts and time-lags time-lags are longer for
more powerful outbursts.

• Period 2
• Amplitude of A2 spike at 37 GHz 1.65 Jy
• Amplitude of B2 spike at 37 GHz 1.75 Jy
• Period 3
• amplitude of A3 spike at 37 GHz 3.65 Jy
• amplitude of B2 spike at 37 GHz 3.65 Jy

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2230114 Due to dependence of time lags on
frequency and amplitude of outburstsperiodicity
in appearance of spikes can be observed only on
average.
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Conclusions

• Frequency dependent time-lags are defined and
  approximated by exponential function of
  frequency
• Delay of 4.8 GHz outburst relative to 37 GHz
  outburst varies from 0.3 to 1.2 yr
• Index of exponential function changes from -0.3
  to 2.2
• Outbursts in sources 0528134 and 2230114 split
  into narrow ( 1 yr) spikes
• Both time-lags and indexes of exponential
  functions changes from one spike to another.

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2230114, CTA 102 Quasi-period in activity

• Bright outbursts in emission of CTA 102 repeat
  every (8.040.30) yr.
• First maximum in the next bright outburst is
  expected near 2005.5.
• Amplitudes of individual spikes within outbursts
  change but their relative positions are
  preserved.
• There is s correlation between time-lags and
  amplitudes of activity brighter outbursts show
  greater time-lags.