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Description
We present RadioAstron Space VLBI imaging observations of the BL Lac object S5 0716+71 made on 2015 January 3-4 at a frequency of 22GHz (wavelength {lambda}=1.3cm). The observations were made in the framework of the AGN Polarization Key Science Program. The source was detected on projected space-ground baselines up to 70833km (5.6 Earth diameters) for both parallel-hand and cross-hand interferometric visibilities. We have used these detections to obtain a full-polarimetric image of the blazar at an unprecedented angular resolution of 24{mu}as, the highest for this source to date. This enabled us to estimate the size of the radio core to be <12x5{mu}as and to reveal a complex structure and a significant curvature of the blazar jet in the inner 100{mu}as, which is an indication that the jet viewing angle lies inside the opening angle of the jet conical outflow. Fairly highly (15%) linearly polarized emission is detected in a jet region 19{mu}as in size, located 58{mu}as downstream from the core. The highest brightness temperature in the source frame is estimated to be >2.2x10^13^K for the blazar core. This implies that the inverse-Compton limit must be violated in the rest frame of the source, even for the largest Doppler factor {delta}~25 reported for 0716+714.
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