Name of the Speaker(s): Vicente, L., Charlot., and Sol, H.
Institution: (DARC) Observatoire de Meudon
Title of the communication: VLBI maps of a sample of blazars
from geodetic data
Preliminary abstract (12 lines max.):
Multi-epoch VLBI maps of nine blazars have been produced from 8.4 and
2.3~GHz geodetic data acquired by the Crustal Dynamics Program. We discuss the
parsec-scale structure of these blazars, some of which have not been previously
mapped with VLBI. Apparent jet component velocities and spectral indices are
estimated. A detailed study of the BL~Lac object OJ287 is presented, based on
ten successive 8.4~GHz maps at intervals of a few months. This intensive
monitoring suggests that the radio knots in the VLBI jet of OJ287 move along
a helical trajectory.