Snmek 1

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Extraction of blazar data from plate stacks
Presented by Milan Basta
PhD supervisor Rene Hudec
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What do blazars look like?
i. e. What do we see when observing blazars?

• ARE POINT-LIKE IN THE SKY

• HAVE NON-STELLAR CONTINUUM AND SPECTRA
• - i.e. spectra different than normal galaxies
• - continuum covers the radio up to the
  gamma-ray bands
• - often having no or weak spectral lines

• ARE HIGHLY AND RAPIDLY VARIABLE
• - in total flux, continuum shape and
  polarization
• - with the highest variability in the
  gamma-rays
• - time scales of variability can be as short as
  several minutes

• SUPERLUMINAL MOTION IS OBSERVED
• - i.e. apparent speeds higher than the speed of
  light

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Some of the long-term blazar light curves
3C 279, Optical band
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Some of the long-term blazar light curves
3C 279, IR
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Some of the long-term blazar light curves
3C 279, Indices
V-B -0.9
J-B -2.2
J-K 1.9
J-H 0.9
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Some of the long-term blazar light curves
3C 279, Composite
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Epochs to mine the data in (straight)
Data gaps, and bare eye visible patterns in the
dataset

• If big outbursts in 88, 76 37
• (marked with green arrows)
• are approximately equally separated
• ? period of 12-13 years ?
• Search 1963 (-2 yr),1950 (-2 yrs) (red arrows)

2. Wave pattern (in green) ? 50 year period
object bright in 1920s, faint round 1900
3. Data gaps (marked in red) in 1951 -1965
before 1930
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Epochs to mine the data (Fourier analysis) I
Periodicity patterns in the dataset, theory
Fourier transform
Discrete Fourier transform (even sampling)
Discrete Fourier transform (uneven sampling the
case of astronomy)
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Epochs to mine data (wavelets analysis) I
Even uneven sampling, theory
Wavelet transform
Wavelet series (dyadic sampling of parameters)
Implemented by pyramidal algorithm
Discrete Wavelet transform (even sampling)
Wavelet transform as projection
Weighted wavelet Z-transform, Foster 1996,
(uneven sampling)
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Epochs to mine data (Four wavelets)
Periodicity patterns in the dataset, applied to
3C 279
26 yr, 7 yr period?
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Epochs to mine data (literature and models)
To support or to reject literature
Period 7.1 - 0.44 yrs
Implies the following outbursts in the past
1930.2 (-0.5), 1923.1 (-1), 1916.0 (- 1.5),
1908.9 (- 2.0), 1901.8 (- 2.5)
Fan, MNRAS, 1999, 308, 1032
Jet precession period 22 yrs
Implies the following outbursts 1965-1966,
1915-1916
Abraham and Carrara, AJ, 1998, 469, 172
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Harvard data
Plate series
http//tdc-www.harvard.edu/plates/
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Harvard data
Plate series and their specifications (including
limiting magnitudes)
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Harvard data
A plates, year and spatial distribution
Temporal distribution
Spatial distribution
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Blazars in our sample
Blazars we intend to mine the data for

• On 231 13.6-year period in the optical band

• Mkn 421 23-year period in the optical band

• BL Lac

• 0109224 11.6-year base-flux level oscillations

• 3C 345 5- and 11-year periodicity in the optical
  band

• Mkn 501 23-day variation in the X-ray and TeV band

• AO 023516 5.7-year periodicity in the radio,
  2.95-year in the optical

• 3C 279 7.1-year in the near IR, 22-year of jet
  components emission

• PKS 0420-014 13-months between optical outbursts

• 3C 66a 2.5-year, 275-day 64-day periodicity in
  the optical band

• 0716714 0.7-year quasiperiodic ejection of VLBA
  components