We present results of long-term high-frequency VLBI monitoring of the relativistic jet in 3C 279 , consisting of 18 epochs at 22 GHz from 1991 to 1997 and 10 epochs at 43 GHz from 1995 to 1997 .
Three major results of this study are : apparent speeds measured for six superluminal components range from 4.8 to 7.5 c ( H _ { 0 } =70 km s ^ { -1 } Mpc ^ { -1 } , q _ { 0 } =0.1 ) , variations in the total radio flux are due primarily to changes in the VLBI core flux , and the uniform-sphere brightness temperature of the VLBI core is \sim 1 \times 10 ^ { 13 } K at 22 GHz after 1995 , one of the highest direct estimates of a brightness temperature .
If the variability brightness temperature measured for 3C 279 by Lähteenmäki & Valtaoja is an actual value and not a lower limit , then the rest-frame brightness temperature of 3C 279 is quite high and limited by inverse Compton effects rather than equipartition .

The parsec-scale morphology of 3C 279 consists of a bright , compact VLBI core , a jet component ( C4 ) that moved from \sim 2 mas to \sim 3.5 mas from the core during the course of our monitoring , and an inner jet that extends from the core to a stationary component , C5 , at \sim 1 mas from the core .
Component C4 followed a curved path , and we reconstruct its three-dimensional trajectory using polynomial fits to its position versus time .
Component C5 faded with time , possibly due to a previous interaction with C4 similar to interactions seen in simulations by Gómez et al .
Components in the inner jet are relatively short-lived , and fade by the time they reach \sim 1 mas from the core .
The components have different speeds and position angles from each other , but these differences do not match the differences predicted by the precession model of Abraham & Carrara .
Although VLBI components were born about six months prior to each of the two observed \gamma -ray high states , the sparseness of the \gamma -ray data prevents a statistical analysis of possible correlations .