Space-VLBI Polarimetry of the BL Lac Object S5 0716+714: Rapid Polarization Variability in the VLBI core

Abstract

To determine the location of the intra-day variable (IDV) emission region within the jet of the BL Lac object S5 0716+714, a multi-epoch VSOP polarization experiment was performed in Autumn 2000. To detect, image, and monitor the short term variability of the source, three space-VLBI experiments were performed with VSOP at 5 GHz, separated in time by six days and by one day. Quasi-contemporaneous flux density measurements with the Effelsberg 100 m radio telescope during the VSOP observations revealed variability of about 5% in total intensity and up to 40% in linear polarization in less than one day. Analysis of the VLBI data shows that the variations are located inside the VLBI core component of 0716+714. In good agreement with the single-dish measurements, the VLBI ground array images and the VSOP images, both show a decrease in the total flux density of ~20 mJy and a drop of ~5 mJy in the linear polarization of the VLBI core. During the observing interval, the polarization angle rotated by about 15 degrees. No variability was found in the jet. The high angular-resolution VSOP images are not able to resolve the variable component and set an upper limit of <0.1 mas to the size of the core component. From the variability timescales we estimate a source size of a few micro-arcseconds and brightness temperatures exceeding 10^15 K. We discuss the results in the framework of source-extrinsic (interstellar scintillation induced) and source-intrinsic IDV models.

arXiv comment15 pages, 10 figures, A&A in press, minor language editing to match the final version

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Cited by in corpus (16)

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• Multiwavelength Intraday Variability of the BL Lac S5 0716+714
• Testing the inverse-Compton catastrophe scenario in the intra-day variable blazar S5 0716+71: II. A search for intra-day variability at millimetre wavelengths with the IRAM 30 m telescope
• The IDV source J1128+5925, a new candidate for annual modulation?
• Multi-frequency monitoring of gamma-ray loud blazars: I. Light curves and spectral energy distributions
• Simultaneous MITSuME gRI monitoring of S5 0716+714
• High Resolution Radio Astronomy Using Very Long Baseline Interferometry
• Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron. III. Blazar S5 0716+71 at microarcsecond resolution
• Frequency dependent core shifts and parameter estimation for the blazar 3C 454.3
• The variability of blazars throughout the electromagnetic spectrum
• Interferometric Monitoring of Gamma-ray Bright AGNs: S5 0716+714
• Very Long Baseline Array observations of the Intraday Variable source J1128+592
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