Proper Motions of Jets on the Kiloparsec Scale: New Results with HST
  The Hubble Space Telescope recently celebrated 25 years of operation. Some of
the first images of extragalactic optical jets were taken by HST in the
mid-1990s; with time baselines on the order of 20 years and state-of-the-art
astrometry techniques, we are now able to reach accuracies in proper-motion
measurements on the order of a tenth of a milliarcsecond per year. We present
the results of a recent HST program to measure the kiloparsec-scale proper
motions of eleven nearby optical jets with Hubble, the first sample of its
kind. When paired with VLBI proper-motion measurements on the parsec scale, we
are now able to map the full velocity profile of these jets from near the black
hole to the final deceleration as they extend out into and beyond the host
galaxy. We see convincing evidence that weak-flavor jets (i.e., FR Is) have a
slowly increasing jet speed up to 100 pc from the core, where superluminal
components are first seen.
