VERY-LONG-BASE-LINE RADIO INTERFEROMETRY (VLBI) OBSERVATIONS OF GAMMA-RAY BLAZARS - RESULTS FROM MILLIMETER-VLBI OBSERVATIONS

VLBI observations of the extremely gamma-bright blazar PKS 0528+134 at 8, 22, 43, and 86 GHz reveal a strongly bent one-sided-core jet structure with at least three moving and two apparently stationary jet components. At the highest observing frequencies the brightest and most compact jet component (the VLBI core) is unresolved with an upper limit to its size of approximate to 50 microarcsec corresponding to approximate to 0.2 parsec [H-0 = 100 km . s(-1). Mpc(-1) (megaparsc(-1)), q(0) = 0.5, where H-0 is Hubble constant and go is the deceleration parameter]. Two 86-GKz VLBI observations performed in 1993.3 and 1994.0 reveal a new jet component emerging with superluminal speed from the core. Linear hack-extrapolation of its motion yields strong evidence that the ejection of this component is related to an outburst in the millimeter regime and a preceding intense flare of the gamma-flux density observed in early 1993. This and the radio/optical ''light curves'' and VLBI data for two other sources (S5 0836+710 and 3C 454.3) suggest that the observed gamma-radiation might be Doppler-boosted and perhaps is closely related to the physical processes acting near the ''base'' of the highly relativistic jets observed in quasars.