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J/ApJ/835/275  OJ 287 flux & polarization during 2016 outburst  (Rakshit+, 2017)

Flux and polarization variability of OJ 287 during the early 2016 outburst. Rakshit S., Stalin C.S., Muneer S., Neha S., Paliya V.S. <Astrophys. J., 835, 275-275 (2017)> =2017ApJ...835..275R (SIMBAD/NED BibCode)
ADC_Keywords: Photometry, RI ; Polarization ; BL Lac objects Keywords: BL Lacertae objects: individual: OJ 287; galaxies: photometry; polarization Abstract: The gamma-ray blazar OJ 287 was in a high activity state during 2015 December-2016 February. Coinciding with this high brightness state, we observed this source for photometry on 40 nights in R-band and for polarimetry on nine epochs in UBV RI bands. During the period of our observations, the source brightness varied from 13.20±0.04 mag to 14.98±0.04mag and the degree of polarization (P) fluctuated between 6.0%±0.3% and 28.3%±0.8% in R-band. Focusing on intranight optical variability (INOV), we find a duty cycle of about 71% using χ2-statistics, similar to that known for blazars. From INOV data, the shortest variability timescale is estimated to be 142±38min, yielding a lower limit of the observed Doppler factor δ0=1.17, the magnetic field strength B≤3.8G, and the size of the emitting region Rs<2.28x1014cm. On internight timescales, a significant anticorrelation between R-band flux and P is found. The observed P at U-band is generally larger than that observed at longer-wavelength bands, suggesting a wavelength-dependent polarization. Using V-band photometric and polarimetric data from Steward Observatory obtained during our monitoring period, we find a varied correlation between P and V-band brightness. While an anticorrelation is sometimes seen between P and V-band magnitude, no correlation is seen at other times, thereby suggesting the presence of more than one short-lived shock component in the jet of OJ 287. Description: Photometric observations in R-band were carried out with the 0.75m telescope at the Vainu Bappu Observatory (VBO) in Kavalur, India. Polarimetric observations were carried out on a total of nine nights; of these, on six nights single-epoch multiband UBV RI observations were performed, and on three nights continuous monitoring was done in R-band. For polarimetric observations, two telescopes were used: the 104cm telescope, located at VBO, and the 104cm Sampurnand telescope, located at the Aryabhatta Research Institute for Observational Sciences (ARIES), Nainital. In addition to the UBV RI bands, we also obtained polarimetric measurements in the light integrated in the V-I spectral region; we refer to this band as R'. Objects: ------------------------------------------------- RA (ICRS) DE Designation(s) ------------------------------------------------- 08 54 48.87 +20 06 30.6 OJ 287 = OHIO J 287 ------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 23 40 Log of photometric observation table2.dat 46 46 Results of polarization observations fig2.dat 26 660 Long term variation of R-band magnitude
See also: J/ApJS/95/1 : Atlas of Quasar Energy Distributions (Elvis+ 1994) J/A+AS/116/403 : VRI photom. of stars in 12 BL Lac objects (Fiorucci+, 1996) J/A+AS/129/569 : BVRI photometry of OJ 287 (Jia Guibin+ 1998) J/A+AS/132/83 : BVRI photometry of 7 BL Lac objects (Bai+ 1998) J/A+AS/136/455 : BVRI photometry of 3 BL Lac objects (Bai+, 1999) J/ApJ/522/846 : Optical monitoring of GeV loud blazars (Xie+, 1999) J/A+A/385/55 : Long-Term Polarization of BL Lac (Hagen-Thorn+ 2002) 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/AJ/134/799 : Multiwaveband polarimetry of 15 AGN (Jorstad+, 2007) J/ApJ/672/40 : AO 0235+164 outburst in 2006 December (Hagen-Thorn+, 2008) J/MNRAS/385/823 : UBVRI light curves of OJ 287 (Zheng+, 2008) J/MNRAS/402/2087 : Opt. polarization of OJ 287 in 2005-2009 (Villforth+, 2010) J/AJ/141/65 : BATC ceimo light curves of OJ 287 (Dai+, 2011) J/MNRAS/421/1861 : OJ287 polarization and VLBI jet direction (Valtonen+, 2012) J/ApJ/747/63 : 7mm VLBA observations of BL Lac object OJ287 (Agudo+, 2012) J/ApJ/764/5 : Photom. of 2012 precursor flare in OJ287 (Pihajoki+, 2013) J/A+A/559/A20 : Historical outbursts of OJ287 (Hudec+, 2013) J/ApJ/789/135 : Gamma-ray bright blazars spectrophotom. (Williamson+, 2014) J/A+A/588/A45 : R-band polarisation of stars toward Gal 110-13 (Neha+, 2016) J/A+A/597/A80 : GMVA 86GHz images of OJ 287 (Hodgson+, 2017) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 11 A11 "D/M/Y" Date UT date of the observation 13- 14 I2 --- N [2/30] Number of data points in differential light curve (DLC) 16- 19 I4 s Exp [300/1800] Exposure time 21- 23 F3.1 h Dur [0.2/4] Duration of monitoring
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 11 A11 "D/M/Y" Date UT date of observation 13- 14 A2 --- Band Observing band (UBV RI R') (1) 16- 27 F12.4 d JD Julian date of the observation 29- 32 F4.1 % Pol [6/38.7] Degree of polarization 34- 36 F3.1 % e_Pol [0.2/3] Pol uncertainty 38- 42 F5.1 deg PA [58.6/130.6] Polarization position angle 44- 46 F3.1 deg e_PA [0.3/3.1] PA uncertainty
Note (1): R' is the integrated polarization in the VRI spectral region.
Byte-by-byte Description of file: fig2.dat
Bytes Format Units Label Explanations
1- 13 F13.5 d JD Julian Date of the observation 15- 20 F6.3 mag Rmag [13.2/15] Apparent R band magnitude 22- 26 F5.3 mag e_Rmag [0.04/0.05] Error in Rmag
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 04-Sep-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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