RoboPol: First season rotations of optical polarization plane in blazars

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We present first results on polarization swings in optical emission of blazars obtained by RoboPol, a monitoring program of an unbiased sample of gamma-ray bright blazars specially designed for effective detection of such events.

• A possible connection of polarization swing events with periods of high activity in gamma rays is investigated using the dataset obtained during the first season of operation.
• It was found that the brightest gamma-ray flares tend to be located closer in time to rotation events, which may be an indication of two separate mechanisms responsible for the rotations.
• Blazars with detected rotations have significantly larger amplitude and faster variations of polarization angle in optical than blazars without rotations.