Rapid Variability in S5 0716+714 Across the Electromagnetic Spectrum

Wagner, S. J.; Witzel, A.; Heidt, J.; Krichbaum, T. P.; Qian, S. J.; Quirrenbach, A.; Wegner, R.; Aller, H.; Aller, M. F.; Anton, K.; Appenzeller, I.; Eckart, A.; Kraus, A.; Naundorf, C. E.; Kneer, R.; Steffen, W.; Zensus, J. A.

doi:10.1086/117954

Cited by 204 publications

(221 citation statements)

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“…Correlated intraday variations in optical and radio frequencies have been reported for this source (Quirrenbach et al 1991). It is also a gamma-ray emitting object associated with an FR II radio source (Wagner et al 1996;von Montigny et al 1995;Chen et al 2008;Villata et al 2008). Observations over a period of ten years indicate it experiences nearly continuous micro-variability activity (Humrickhouse & Webb 2008;Webb et al 2010), with duty cycle of about 95.3%.…”

Section: Introductionmentioning

confidence: 76%

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: Introductionmentioning

confidence: 76%

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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“…There is a series of papers covering flux variability studies (Quirrenbach et al 1991;Wagner et al 1996, and references therein) and morphological/kinematic studies at radio frequencies (Witzel et al 1988;Jorstad et al 2001;Antonucci et al 1986;Bach et al 2005;Rastorgueva et al 2011, and references therein). Intraday variability at radio wavelengths is likely to be a mixture of intrinsic and extrinsic mechanisms (due to interstellar scintillation).…”

Section: Introductionmentioning

confidence: 99%

Radio to gamma-ray variability study of blazar S5 0716+714

Rani

Krichbaum

Fuhrmann

et al. 2013

A&A

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We present the results of a series of radio, optical, X-ray, and γ-ray observations of the BL Lac object S50716+714 carried out between April 2007 and January 2011. The multifrequency observations were obtained using several ground-and space-based facilities. The intense optical monitoring of the source reveals faster repetitive variations superimposed on a long-term variability trend on a time scale of ∼350 days. Episodes of fast variability recur on time scales of ∼60−70 days. The intense and simultaneous activity at optical and γ-ray frequencies favors the synchrotron self-Compton mechanism for the production of the high-energy emission. Two major low-peaking radio flares were observed during this high optical/γ-ray activity period. The radio flares are characterized by a rising and a decaying stage and agrees with the formation of a shock and its evolution. We found that the evolution of the radio flares requires a geometrical variation in addition to intrinsic variations of the source. Different estimates yield robust and self-consistent lower limits of δ ≥ 20 and equipartition magnetic field B eq ≥ 0.36 G. Causality arguments constrain the size of emission region θ ≤ 0.004 mas. We found a significant correlation between flux variations at radio frequencies with those at optical and γ-rays. The optical/GeV flux variations lead the radio variability by ∼65 days. The longer time delays between low-peaking radio outbursts and optical flares imply that optical flares are the precursors of radio ones. An orphan X-ray flare challenges the simple, one-zone emission models, rendering them too simple. Here we also describe the spectral energy distribution modeling of the source from simultaneous data taken through different activity periods.

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“…One of the most prominent sources displaying correlated variability at different wavelengths is 0716+714 (radio and optical) (Quirrenbach et al 1991;Wagner et al 1996). The source OJ287 is another famous example, that has correlated variability in the radio, optical, and infrared (see e.g., Fan & Lin 1999).…”

Section: Periodicities In the Lightcurvesmentioning

confidence: 99%

Tracing the merger-driven evolution of active galaxies using the CJF sample

Karouzos¹,

Britzen²,

Eckart

et al. 2010

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Context. For the evolution of large-scale structures in the Universe, it is unclear whether active galaxies represent a phase that each galaxy undergoes, and whether and to which extent the evolution of black holes at their centers is important. Binary black hole (BBH) systems may play a key role in our understanding of the above questions. Aims. We investigate the Caltech-Jodrell Bank flat-spectrum (CJF) sample to identify evidence that supports the merger-driven evolution scheme of active galaxies, and search for tracer-systems of active galactic nucleus (AGN) evolution and possible BBH candidates. We discuss the strength of and uncertainty in the evidence and formulate a set of selection criteria to detect such tracer-systems. Methods. We conduct an extensive literature search for all available multiwavelength data, particularly in the optical and infrared regime, and morphological information about the CJF sources. We perform a statistical analysis of the properties of this sample. Results. We find 1 ULIRG (Mrk 231) included in the CJF prototype of a transitory system. In total, 28.6% of the CJF sources with z ≤ 0.4 are distorted or have a companion. Given the unbiased sample used here, this provides strong evidence of the ubiquity of the merger phenomenon in the context of active galaxies. We find a correlation between the radio and the near-infrared luminosity of the high-luminosity sources, interpreted in the context of the interplay between a star-formation and AGN component. We find a connection between variability and evolutionary transitory systems, as selected on the basis of their near-infrared colors. We select 28 sources that trace the different evolution phases of an AGN, as well as a number of the most promising BBH candidates. We find 4 sources with almost periodical variability in the optical and radio on similar timescales.

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Rapid Variability in S5 0716+714 Across the Electromagnetic Spectrum

Cited by 204 publications

References 0 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

Radio to gamma-ray variability study of blazar S5 0716+714

Tracing the merger-driven evolution of active galaxies using the CJF sample

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