Detection of Polarimetric Variations Associated with the Shortest Time-Scale Variability in S5 0716$ + $714

Understand

We present the result of near-infrared and optical observations of the BL Lac object S5 0716$ + $714 carried out by the KANATA telescope.

• S5 0716$ + $714 has both a long term high-amplitude variability and a short-term variability within a night.
• The shortest variability (microvariability) time-scale is important for understanding the geometry of jets and magnetic field, because it provides a possible minimum size of variation sources.
• Here, we report the detection of 15-min variability in S5 0716$ + $714, which is one of the shortest time-scales in optical and near-infrared variations observed in blazars.