J/A+A/620/A185 Long-term optical monitoring of TeV Blazars (Nilsson+, 2018)
Long-term optical monitoring of TeV emitting Blazars
I. Data analysis.
Nilsson K., Lindfors E., Takalo L.O., Reinthal R., Berdyugin A.,
Sillanpaeae A., Ciprini S., Halkola A., Heinaemaeki P., Hovatta T.,
Kadenius V., Nurmi P., Ostorero L., Pasanen M., Rekola R., Saarinen J.,
Sainio J., Tuominen T., Villforth C., Vornanen T., Zaprudin B.
<Astron. Astrophys. 620, A185 (2018)>
=2018A&A...620A.185N 2018A&A...620A.185N (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; Photometry, CCD
Keywords: galaxies: active - BL Lacertae objects: general -
methods: data analysis
Abstract:
We present ten years of R-band monitoring data of 31 northern blazars
which were either detected at very high-energy (VHE) gamma rays or
listed as potential VHE gamma-ray emitters. The data comprise 11820
photometric data points in the R-band obtained in 2002-2012. We
analyzed the light curves by determining their power spectral density
(PSD) slopes assuming a power-law dependence with a single slope beta
and a Gaussian probability density function (PDF). We used the
multiple fragments variance function (MFVF) combined with a
forward-casting approach and likelihood analysis to determine the
slopes and perform extensive simulations to estimate the uncertainties
of the derived slopes. We also looked for periodic variations via
Fourier analysis and quantified the false alarm probability through a
large number of simulations. Comparing the obtained PSD slopes to
values in the literature, we find the slopes in the radio band to be
steeper than those in the optical and gamma rays. Our periodicity
search yielded one target, Mrk 421, with a significant (p<5%)
period. Finding one significant period among 31 targets is consistent
with the expected false alarm rate, but the period found in Mrk 421 is
very strong and deserves further consideration.
Description:
R-band magnitudes of 31 blazars observed in 2002-2012.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 90 31 Main properties of the targets and observing log
refs.dat 71 60 References
lc/* . 31 Individual light curves
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See also:
VII/274 : The Roma BZCAT - 5th edition (Massaro+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- n_Target [*] Note on Name (1)
3- 14 A12 --- Target Target name
17- 21 F5.3 --- z ?=- Redshift
23- 29 A7 --- Type Broadband type (2)
31 A1 --- TeV [y-] is the target detected at TeV energies?
33- 37 F5.3 mag AR Galactic extinction in the R-band,
obtained from the NED
39- 42 I4 --- Nfrms Number of CCD frames
44- 46 I3 --- Nobs Number of data points
48- 73 A26 --- Ref References to papers where parts of these data
have been used before, in refs.dat file
75- 90 A16 --- FileName Name of the file with light data in
subdirectory lc
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Note (1): * for targets belong to the long-term monitoring sample of 24 targets
drawn from Costamante & Ghisellini (2002A&A...384...56C 2002A&A...384...56C).
Note (2): Broadband type:
FSRQ/BL division from the Roma-BZCAT (5th Edition, Massaro et al.,
2015Ap&SS.357...75M 2015Ap&SS.357...75M, Cat. VII/274),
LBL/IBL/HBL classification from this work
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 49 A26 --- Aut Author's name
51- 71 A21 --- Com Comments
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Byte-by-byte Description of file: lc/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Target Target name
15- 27 F13.5 d JD Julian day
29- 34 F6.3 mag Rmag R-band magnitude
36- 40 F5.3 mag e_Rmag R-band magnitude error
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Acknowledgements:
Kari Nilsson, kani(at)utu.fi, Finnish Centre for Astronomy with ESO
(End) Kari Nilsson [FINCA], Patricia Vannier [CDS] 17-Dec-2018