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MULTIFREQUENCY PHOTO-POLARIMETRIC WEBT OBSERVATION CAMPAIGN on the BLAZAR S5 0716+714: SOURCE MICROVARIABILITY and SEARCH for CHARACTERISTIC TIMESCALES
- Source :
- SCOPUS0004637X-2016-831-1-SID84994669319
- Publication Year :
- 2016
-
Abstract
- Here we report on the results of the WEBT photo-polarimetric campaign targeting the blazar S5~0716+71, organized in March 2014 to monitor the source simultaneously in BVRI and near IR filters. The campaign resulted in an unprecedented dataset spanning $\sim 110$\,h of nearly continuous, multi-band observations, including two sets of densely sampled polarimetric data mainly in R filter. During the campaign, the source displayed pronounced variability with peak-to-peak variations of about $30\%$ and "bluer-when-brighter" spectral evolution, consisting of a day-timescale modulation with superimposed hourlong microflares characterized by $\sim 0.1$\,mag flux changes. We performed an in-depth search for quasi-periodicities in the source light curve; hints for the presence of oscillations on timescales of $\sim 3$\,h and $\sim 5$\,h do not represent highly significant departures from a pure red-noise power spectrum. We observed that, at a certain configuration of the optical polarization angle relative to the positional angle of the innermost radio jet in the source, changes in the polarization degree led the total flux variability by about 2\,h; meanwhile, when the relative configuration of the polarization and jet angles altered, no such lag could be noted. The microflaring events, when analyzed as separate pulse emission components, were found to be characterized by a very high polarization degree ($> 30\%$) and polarization angles which differed substantially from the polarization angle of the underlying background component, or from the radio jet positional angle. We discuss the results in the general context of blazar emission and energy dissipation models.<br />16 pages, 17 Figures; ApJ accepted
- Subjects :
- Astrophysics::High Energy Astrophysical Phenomena
Polarimetry
jets [galaxies]
FOS: Physical sciences
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
symbols.namesake
0103 physical sciences
Blazar
010303 astronomy & astrophysics
Infrared cut-off filter
acceleration of particles
High Energy Astrophysical Phenomena (astro-ph.HE)
Physics
polarization
Brewster's angle
individual (S5 0716+714) [BL Lacertae objects]
010308 nuclear & particles physics
Spectral density
Astronomy and Astrophysics
Optical polarization
Light curve
Polarization (waves)
non-thermal [radiation mechanisms]
Space and Planetary Science
active [galaxies]
symbols
individual: S5 0716+714 [BL Lacertae objects]
Astrophysics - High Energy Astrophysical Phenomena
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- SCOPUS0004637X-2016-831-1-SID84994669319
- Accession number :
- edsair.doi.dedup.....9ab799c61cfce0939f50ac82096cec95