
%0 Journal Article
%A Valtaoja, E. 
%A Savolainen, T. 
%A Wiik, K. 
%A L&auml;hteenm&auml;ki, A. 
%T Millimetre Continuum Variations, VLBI Structure and Gamma Rays: Investigating Shocked Jet Physics
%J Publications of the Astronomical Society of Australia
%D 2002/06/28
%V 19
%N 1
%P 117-121
%K black hole physics &#8212; galaxies: active &#8212; galaxies: jets &#8212; X-rays: binaries &#8212; radio continuum: galaxies &#8212; radio continuum: stars
%R https://doi.org/10.1071/AS01117
%U https://www.publish.csiro.au/paper/AS01117 
%X We compare the total flux density variations and the VLBI structural variations in a sample of 27 gamma-ray blazars. We find that all the radio variations are due to shocks; the flux of the underlying jet remains constant. A large fraction of the shocks grow and fade within the innermost 0.1 mas, appearing only as &#8216;core flares&#8217;. Comparisons with the EGRET data show that gamma-ray flares must come from the shocks, not from the jet. At the time of an EGRET flare, the shock is typically already over a parsec downstream from the radio core, beyond the accretion disk and/or the broad line region (BLR) photon fields. Thus, present models for gamma-ray production are inadequate, since they typically model the gamma-ray inverse Compton flux as coming from the jet, with significant disk or BLR external Compton components. 
