1999A&A...351..147G

We present a model to study the evolution of pair components moving in symmetric jets. The model fits the observed components flux ratio evolution obtaining the geometric (sizes, opening angles, system orientation with respect to the observer) and kinematic (speeds, expansion velocities) properties of the system. We have applied the model to the pair of components originated by the prominent radio flare emitted by the galactic source GRS 1915+105 in March 1994, and described in Mirabel & Rodriguez (1994Natur.371...46M) We have found an asymmetry between the approaching and receding jets which implies a slower expansion velocity of the receding component and may account for the slower steepening of its spectrum necessary to fit our model. Each component is found to have similar longitudinal and transverse expansion velocities.