J/A+A/645/A137 BVRI light curves of PG 1553+113 (Agarwal+, 2021)
Multi-band behaviour of the TeV blazar PG 1553+113 in optical range on diverse
timescales. Flux and spectral variations.
Agarwal A., Mihov B., Andruchow I., Cellone S. A., Anupama G. C.,
Agrawal V., Zola S., Slavcheva-Mihova L., Ozdonmez A., Ege E., Raj A.,
Mammana L., Zibecchi L., Fernandez-Lajus E.
<Astron. Astrophys. 645, A137 (2021)>
=2021A&A...645A.137A 2021A&A...645A.137A (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; Photometry, UBVRI ; Photometry, CCD
Keywords: galaxies: general - galaxies: active - BL Lacertae objects: general -
BL Lacertae objects: individual: PG 1553+113
Abstract:
The TeV BL Lac object PG 1553+113 is one of the primary candidates for
a binary supermassive black hole system.
We study the flux and spectral variability of PG 1553+113 on
intra-night to long-term timescales using (i) BVRI data collected over
76 nights from January 2016 to August 2019 involving nine optical
telescopes and (ii) historical VR data (including ours) obtained for
the period from 2005 to 2019. We analysed the light curves using
various statistical tests, fitting and cross-correlation techniques,
and methods for the search for periodicity. We examined the
colour-magnitude diagrams before and after the corresponding light
curves were corrected for the long-term variations. Our intra-night
monitoring, supplemented with literature data, result in a low duty
cycle of ~(10-17)%. In April 2019, we recorded a flare, which marks
the brightest state of PG 1553+113 for the period from 2005 to 2019:
R∼13.2mag. This flare is found to show a clockwise spectral
hysteresis loop on its VR colour-magnitude diagram and a time lag in
the sense that the V-band variations lead the R-band ones. We obtain
estimates of the radius, the magnetic field strength, and the electron
energy that characterize the emission region related to the flare. We
find a median period of (2.21±0.04) years using the historical
light curves. In addition, we detect a secondary period of about 210
days using the historical light curves corrected for the long-term
variations. We briefly discuss the possible origin of this period.
Description:
Light curves of the TeV blazar PG 1553+113 are presented. The data
were obtained in the Johnson-Cousins BVRI passbands from January 2016
to August 2019 involving nine optical telescopes and used to study the
intra-night and long-term variability of the blazar. Details on
reduction, photometry, calibration, and analysis are described in the
paper.
Objects:
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RA (2000) DE Designation(s)
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15 55 43.0 +11 11 24 PG 1553+113 = QSO B1553+113
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
data-b.dat 26 380 Calibrated B-band light curve
data-v.dat 26 487 Calibrated V-band light curve
data-r.dat 26 2014 Calibrated R-band light curve
data-i.dat 26 470 Calibrated I-band light curve
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Byte-by-byte Description of file: data-b.dat data-i.dat data-r.dat data-v.dat
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Bytes Format Units Label Explanations
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1- 10 F10.5 d MJD Modified Julian Date (JD-2450000)
12- 17 F6.3 mag mag Calibrated magnitude in Filter Band
19- 24 F6.4 mag e_mag Error on magnitude
26 A1 --- Band [BVRI] Band
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Acknowledgements:
Boyko Mihov, bmihov(at)astro.bas.bg
(End) Boyko Mihov [IANAO, Bulgaria], Patricia Vannier [CDS] 26-Oct-2020