J/AJ/157/95 Optical variability of OJ 287 in 2016-2017 (Gupta+, 2019)
Characterizing optical variability of OJ 287 in 2016-2017.
Gupta A.C., Gaur H., Wiita P.J., Pandey A., Kushwaha P., Hu S.M.,
Kurtanidze O.M., Semkov E., Damljanovic G., Goyal A., Uemura M., Darriba A.,
Chen Xu, Vince O., Gu M.F., Zhang Z., Bachev R., Chanishvili R., Itoh R.,
Kawabata M., Kurtanidze S.O., Nakaoka T., Nikolashvili M.G., Stawarz L.,
Strigachev A.
<Astron. J., 157, 95 (2019)>
=2019AJ....157...95G 2019AJ....157...95G (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; Photometry, UBVRI
Keywords: BL Lacertae objects: general -
BL Lacertae objects: individual (OJ 287) - techniques: photometric -
techniques: polarimetric
Abstract:
We report on a recent multiband optical photometric and polarimetric
observational campaign of the blazar OJ 287 that was carried out during
2016 September-2017 December. We employed nine telescopes in Bulgaria,
China, Georgia, Japan, Serbia, Spain, and the United States. We collected
over 1800 photometric image frames in BVRI bands and over 100 polarimetric
measurements over ∼175 nights. In 11 nights with many quasi-simultaneous
multiband (V, R, I) observations, we did not detect any genuine intraday
variability in flux or color. On longer timescales, multiple flaring
events were seen. Large changes in color with respect to time and in a
color-magnitude diagram were seen, and while only a weak systematic
variability trend was noticed in color with respect to time, the
color-magnitude diagram shows a bluer-when-brighter trend. Large changes
in the degree of polarization and substantial swings in the polarization
angle were detected. The fractional Stokes parameters of the polarization
showed a systematic trend with time in the beginning of these observations,
followed by chaotic changes and then an apparently systematic variation
at the end. These polarization changes coincide with the detection and
duration of the source at very high energies as seen by VERITAS. The
spectral index shows a systematic variation with time and V-band magnitude.
We briefly discuss possible physical mechanisms that could explain the
observed flux, color, polarization, and spectral variability.
Description:
Our new optical photometric and polarimetric observational campaigns were
carried out from 2016 September to 2017 December. Photometric observations
were carried out using seven telescopes located in Japan, China, Bulgaria
(two telescopes), Georgia, Serbia, and Spain. Using these seven telescopes,
photometric observations were taken on 174 observing nights, during which
we collected a total of 1829 image frames of OJ 287 in B, V, R, and I
optical photometric bands. We also used the archival optical photometric
and polarimetric observations that are performed at Steward Observatory,
University of Arizona, using the 2.3 m Bok and 1.54 m Kuiper telescopes.
Objects:
-----------------------------------------------------
RA (ICRS) DE Designation(s)
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08 54 48.87 +20 06 30.6 OJ 287 = QSO J0854+2006
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 23 247 Observation log of optical photometric
observations of the blazar OJ 287
table3.dat 121 55 Results of intraday variability (IDV) observations
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See also:
J/A+AS/116/403 : VRI photometry of stars in 12 BL Lac objects
(Fiorucci+, 1996)
J/A+AS/129/569 : BVRI photometry of OJ 287 (Jia Guibin+ 1998)
J/A+A/450/39 : BVRI photometry of 8 red blazars (Gu+, 2006)
J/AJ/132/1256 : eim BATC photometry of OJ 287 (Wu+, 2006)
J/MNRAS/385/823 : UBVRI light curves of OJ 287 (Zheng+, 2008)
J/MNRAS/402/2087 : Optical polarization of OJ 287 in 2005-2009
(Villforth+, 2010)
J/AJ/141/65 : BATC ceimo light curves of OJ 287 (Dai+, 2011)
J/ApJ/764/5 : BR photometry of 2012 precursor flare in OJ287
(Pihajoki+, 2013)
J/A+A/562/A79 : Variability of seven blazars in six bands
(Sandrinelli+, 2014)
J/A+A/597/A80 : GMVA 86GHz images of OJ 287 (Hodgson+, 2017)
J/ApJ/835/275 : OJ 287 flux + polarization during 2016 outburst
(Rakshit+, 2017)
J/A+A/610/A74 : OJ 287 far-infrared photometry (Kidger+, 2018)
J/A+A/619/A88 : High cadence polarization monitoring of OJ287
(Myserlis+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Date of the observation
12 A1 --- Tel Telescope code (1)
14 I1 --- o_Bmag [0/8] Number of B band observations
16- 17 I2 --- o_Vmag [0/72] Number of V band observations
19- 20 I2 --- o_Rmag [0/74] Number of R band observations
22- 23 I2 --- o_Imag [0/74] Number of I band observations
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Note (1): Telescope as follows:
A = 2.3-m Bok Telescope and 1.54-m Kuiper Telescope at Steward Observatory,
Arizona, USA;
B = 1.0-m Cassegrain Telescope in Weihai, China;
C = 2-m Ritchey-Chretien Telescope and 50/70-cm Schmidt Telescope at National
Astronomical Observatory, Rozhen, Bulgaria;
D = 35.6 cm Telescope at Observatorio Astronomico Las Casqueras, Spain;
E = 1.4-m Telescope, Astronomical Station Vidojevica (ASV), Serbia;
F = 70-cm meniscus telescope at Abastumani Observatory, Georgia;
G = 1.5-m KANATA telescope at Higashi-Hiroshima Observatory, Japan.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Date of the observation
12- 16 A5 --- Band Band or color
18- 19 I2 --- Nobs [13/74] Number of observations in Band
21- 24 F4.2 --- F1 [0.01/3.92] The F1 value in the F-test
26- 29 F4.2 --- F2 [0.15/2.76] The F2 value in the F-test
31- 34 F4.2 --- F [0.4/3.1] The F value in the F-test
36- 39 F4.2 --- Fc(0.99) [1.73/4.16] The Fc(0.99) value in the
F-test
41- 44 F4.2 --- Fc(0.999) [2.08/7] The Fc(0.999) value in the F-test
46- 51 F6.2 --- chi2(1) [7.22/320.75] The χ21 value in the
χ2-test
53- 60 F8.2 --- chi2(2) [5.25/16199.26] The χ22 value in the
χ2-test
62- 68 F7.2 --- chi2(av) [6.23/8117.93] The χ2av value in the
χ2-test
70- 75 F6.2 --- chi2(0.99) [26.22/104.01] The χ20.99 value in
the χ2-test
77- 82 F6.2 --- chi2(0.999) [32.91/116.09] The χ20.999 value in
the χ2-test
84- 91 E8.2 --- W1 [0.00308/4.43] The W1 value in the Levene
test
93-100 E8.2 --- p1 [0.0385/0.956] The p1 value in the Levene
test
102-109 E8.2 --- W2 [6.56e-05/19.9] The W2 value in the Levene
test
111-118 E8.2 --- p2 [1.59e-05/0.994] The p2 value in the Levene
test
120-121 A2 --- Var Variable flag (NV=Non-variable)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 03-Jun-2019