The intraday variations of the polarization vector direction in radio source S5 0716+714

Abstract

The bright radio source S5 0716+714, that is usually classified as BL Lac object, is one of the most intensively studied. S5 0716+714 demonstrates extremely peculiar properties such as the shortest time-scale of optical and polarimetric variations observed in blazars. In given paper, the results of 9-hour polarimetric monitoring of S5 0716+714 with the ∼70-second resolution carried out by the 6-m telescope BTA of SAO RAS, are presented. The observation data analysis reveals the variability both in total and polarized light on the 1-1.5-hour time-scale. Since polarization is generated by plasma motion in the magnetic field, the variations of polarization vector are bounded with the magnetic field configuration and the average time-scales specify the size of the emitting region, unresolved directly. We suggest a processed numerically model of the polarization in the jet with the precessing helical magnetic field. Fitting the model discovers that observed short-term variations with the complicated trajectory of polarization vector could be induced by the magnetic field precession with the period T ≈ 15 days.

Stokes-polarimeter for 1-meter telescope

“…Wavelet analysis shows the period of light variations of the object to be 76±10 minutes. The agreement between the period of light variations and that of the variations of the polarization vector are totally consistent with the result that we earlier obtained based on observations made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences [14]. Thus the observations mentioned above show that the task of the polarimetry of relatively bright (about 13-14 m ) starlike objects can be successfully addressed with the "StoP" instrument and the accuracy of both photometry and polarimetry are on a par with those of the results obtained with the 6-m telescope.…”

“…The main task of the "StoP" instrument is to perform high-precision polarimetric observations of starlike objects, and in this sense are unparalleled among attachable equipment for Zeiss-1000 telescope. The technique of the measurement of the polarization of point-like sources with an accuracy of 0.1% was successfully used on the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences equipped with SCORPIO-2 instrument [14], where observations involved the use of an analyzer similar to that incorporated in "StoP"-double Wollaston prism WOLL-2. To test the technique of observations we decided to repeat observations of the blazar S5 0716+714.…”

“…A description of the technique of reverberation mapping observations in interference filters and the first results can be found in Uklein et al [16]. It became clear in recent years that important information about the structure of central AGN regions can be obtained from BLR reverberation mapping in polarized light [15] and from high-precision photometric and polarimetric monitoring of BL Lac objects 2 [14]. It is therefore highly important not only to perform spectropolarimetric observations of AGNs, which allow the masses of supermassive black homes (SMBH) at the centers of galaxies to be independently determined [2], but also to monitor polarized flux in broad lines in objects with equatorial scattering on the dusty tori.…”

A geometrical interpretation for the properties of multiband optical variability of the blazar S5 0716+714

“…Optical radiation is assumed to be synchrotron. Despite the fact that one of the advantages of the TEMZ model is that it provides an explanation for the observed rotation of the electric vector in the wave, Shablovinskaya & Afanasiev (2019) showed that on a time scale of several hours the changes in the electric vector direction in the wave observed for S5 0716+714 correspond to the motion of a particle in the precessing helical magnetic field. The TEMZ model was applied to interpret the IDV flares of the blazar S5 0716+714 (Bhatta et al 2013;Xu et al 2019).…”

Variability of the Blazar 1156+295 in 2005–2020

“…This is especially important for the studies of ultra-fast variations. The results of the first attempts of such observations for one of the blazars (S5 0716+714) were published recently [17].…”