Periodic Oscillations in the Intra-Day Optical Light Curves of the Blazar S5 0716+714

Gupta, Alok C.; Srivastava, A. K.; Wiita, Paul J.

doi:10.1088/0004-637x/690/1/216

Cited by 139 publications

(159 citation statements)

References 56 publications

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“…The amplitude of peaks in the DFT did not decrease drastically as we prewhitened the data, indicating that the periods are not indicative of a true period running through the extended data set. Neither did we find the periods at approximately 25 and 73 min in this flux curve seen previously by Gupta et al (2009). Thus we could not confirm any of the previously detected periods seen in the S 50716 +714 microvariability curves or propose significant new periods.…”

Section: Fourier Transform Analysiscontrasting

confidence: 92%

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The 72-h WEBT microvariability observation of blazar S5 0716 + 714 in 2009

Bhatta

Webb

Hollingsworth

et al. 2013

A&A

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Context. The international Whole Earth Blazar Telescope (WEBT) consortium planned and carried out three days of intensive micro-variability observations of S5 0716+714 from February 22, 2009 to February 25, 2009. This object was chosen due to its bright apparent magnitude range, its high declination, and its very large duty cycle for micro-variations. Aims. We report here on the long continuous optical micro-variability light curve of 0716+714 obtained during the multi-site observing campaign during which the Blazar showed almost constant variability over a 0.5 mag range. The resulting light curve is presented here for the first time.Observations from participating observatories were corrected for instrumental differences and combined to construct the overall smoothed light curve. Methods. Thirty-six observatories in sixteen countries participated in this continuous monitoring program and twenty of them submitted data for compilation into a continuous light curve. The light curve was analyzed using several techniques including Fourier transform, Wavelet and noise analysis techniques. Those results led us to model the light curve by attributing the variations to a series of synchrotron pulses. Results. We have interpreted the observed microvariations in this extended light curve in terms of a new model consisting of individual stochastic pulses due to cells in a turbulent jet which are energized by a passing shock and cool by means of synchrotron emission. We obtained an excellent fit to the 72-hour light curve with the synchrotron pulse model.

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Section: Fourier Transform Analysiscontrasting

confidence: 92%

“…The light curve data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/558/A92 and 73 min in twenty-two well sampled micro-variability curves (Gupta et al 2009). …”

Section: Introductionmentioning

confidence: 99%

The 72-h WEBT microvariability observation of blazar S5 0716 + 714 in 2009

Bhatta

Webb

Hollingsworth

et al. 2013

A&A

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“…Intra-day variabilities (IDVs) have been studied by many authors (Poon et al 2009;Liu et al 2012;Gupta et al 2012;Bhatta et al 2013;Man et al 2016;Lee et al 2016, etc.). Gupta et al (2009) obtained timescales of 25 min; Rani et al (2010) obtained timescales of 15 min; Man et al (2016) obtained timescales of 17.6 min; and Bhatta et al (2016) displayed the variability based on the A&A 605, A43 (2017) peak-to-peak variations of 30% and "bluer-when-brighter" spectral evolution.…”

Section: Introductionmentioning

confidence: 94%

Optical monitoring of BL Lac object S5 0716+714 and FSRQ 3C 273 from 2000 to 2014

Yuan

Fan

Tao

et al. 2017

A&A

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Context. Using the 1.56 m telescope at the Shanghai Observatory (ShAO), China, we monitored two sources, BL Lac object S5 0716+714 and flat spectrum radio quasar (FSRQ) 3C 273. For S5 0716+714, we report 4969 sets of CCD (Charge-coupled Device) photometrical optical observations (1369 for V band, 1861 for R band and 1739 for I band) in the monitoring time from Results. The two sources both show IDV properties for S5 0716+714. The timescales are in the range from 17.3 min to 4.82 h; for 3C 273, the timescale is ∆T = 35.6 min. Based on the periodic analysis methods, we find the periods P V = 24.24 ± 1.09 days, P R = 24.12 ± 0.76 days, P I = 24.82 ± 0.73 days for S5 0716+714, and P = 12.99 ± 0.72, 21.76 ± 1.45 yr for 3C 273. The two sources displayed the "bluer-when-brighter" spectral evolution properties. Conclusions. S5 0716+714 and 3C 273 are frequently studied objects. The violent optical variability and IDV may come from the jet. Gaussian fitting can be used to analyze IDVs. The relations between brightness (flux density) and spectrum are strongly influenced by the frequency.

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“…It is highly variable on timescales from hours to months across all observed wavelengths. Intra-day variability (IDV) has been detected in this blazar (Wagner et al 1996;Stalin et al 2006;Montagni et al 2006;Gupta et al 2009). The IDV in radio band is likely to be intrincic to the source because it is either reported to be correlated with the optical band (Wagner et al 1996) or its spectrum is not consistent with the scintillation (Fuhrmann et al 2008), which…”

Section: Introductionmentioning

confidence: 90%

Multi-frequency VLBA study of the blazar S5 0716+714 during the active state in 2004

Rastorgueva

Wiik

Bajkova

et al. 2011

A&A

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Context. We study the jet kinematics of the blazar S5 0716+714 during its active state in 2003-2004 with multi-epoch VLBI observations.Aims. We present a kinematic analysis of the large-scale (0-12 mas) jet of 0716+714, based on the results of six epochs of VLBA monitoring at 5 GHz. Additionally, we compare kinematic results obtained with two imaging methods based on different deconvolution algorithms. Methods. The blazar 0716+714 has a diffuse large-scale jet, which is very faint compared with the bright compact core. Experiments with simulated data showed that the conventional data reduction procedure based on the CLEAN deconvolution algorithm does not perform well in restoring this type of structure. This might be the reason why previous kinematic studies of this source yielded ambiguous results. In order to obtain accurate kinematics of this source, we independently applied two imaging techniques to the raw data: the conventional method, based on difference mapping, which uses CLEAN deconvolution, and the generalized maximum entropy method (GMEM) realized in the VLBImager package developed at the Pulkovo Observatory in Russia. Results. The results of both methods give us a consistent kinematic scenario: the large-scale jet of 0716+714 is diffuse and stationary. Differences between the inner (0-1 mas) and outer (1-12 mas) regions of the jet in brightness and velocity of the components could be explained by the bending of the jet, which causes the angle between the jet direction and the line of sight to change from ∼5 • to ∼11 • . Conclusions. We tested the performance of the two imaging methods on real data and found that they yield similar kinematic results, but determination of the jet component positions by the conventional method was less precise. The method based on the GMEM algorithm is suitable for kinematic studies. It is especially effective for dim diffuse sources with the average brightness of several mJy with bright point-like features. For the source 0716+714, both methods worked at the limit of their capability.

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Periodic Oscillations in the Intra-Day Optical Light Curves of the Blazar S5 0716+714

Cited by 139 publications

References 56 publications

The 72-h WEBT microvariability observation of blazar S5 0716 + 714 in 2009

The 72-h WEBT microvariability observation of blazar S5 0716 + 714 in 2009

Optical monitoring of BL Lac object S5 0716+714 and FSRQ 3C 273 from 2000 to 2014

Multi-frequency VLBA study of the blazar S5 0716+714 during the active state in 2004

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