A TIGHT CONNECTION BETWEEN GAMMA-RAY OUTBURSTS AND PARSEC-SCALE JET ACTIVITY IN THE QUASAR 3C 454.3

Abstract

We analyze the multifrequency behavior of the quasar 3C 454.3 during three\nprominent \\gamma-ray outbursts: 2009 Autumn, 2010 Spring, and 2010 Autumn. The\ndata reveal a repeating pattern, including a triple flare structure, in the\nproperties of each \\gamma-ray outburst, which implies similar mechanism(s) and\nlocation for all three events. The multi-frequency behavior indicates that the\nlower frequency events are co-spatial with the \\gamma-ray outbursts, although\nthe \\gamma-ray emission varies on the shortest timescales. We determine that\nthe variability from UV to IR wavelengths during an outburst results from a\nsingle synchrotron component whose properties do not change significantly over\nthe different outbursts. Despite a general increase in the degree of optical\nlinear polarization during an outburst, the polarization drops significantly at\nthe peak of the \\gamma-ray event, which suggests that both shocks and turbulent\nprocesses are involved. We detect two disturbances (knots) with superluminal\napparent speeds in the parsec-scale jet associated with the outbursts in 2009\nAutumn and 2010 Autumn. The kinematic properties of the knots can explain the\ndifference in amplitudes of the \\gamma-ray events, while their millimeter-wave\npolarization is related to the optical polarization during the outbursts. We\ninterpret the multi-frequency behavior within models involving either a system\nof standing conical shocks or magnetic reconnection events located in the\nparsec-scale millimeter-wave core of the jet. We argue that \\gamma-ray\noutbursts with variability timescales as short as ~ 3 hr can occur on parsec\nscales if flares take place in localized regions such as turbulent cells.\n