Title: Snmek 1
1Extraction of blazar data from plate stacks
Presented by Milan Basta
PhD supervisor Rene Hudec
2What 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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7Some of the long-term blazar light curves
3C 279, Optical band
8Some of the long-term blazar light curves
3C 279, IR
9Some 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
10Some of the long-term blazar light curves
3C 279, Composite
11Epochs 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
12Epochs 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)
13Epochs 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)
14Epochs to mine data (Four wavelets)
Periodicity patterns in the dataset, applied to
3C 279
26 yr, 7 yr period?
15Epochs 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
16Harvard data
Plate series
http//tdc-www.harvard.edu/plates/
17Harvard data
Plate series and their specifications (including
limiting magnitudes)
18Harvard data
A plates, year and spatial distribution
Temporal distribution
Spatial distribution
19Blazars 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
- 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