The parsec-scale jets in 3C 273 and 3C 345

We present recent centimeter-wavelength 'global-array' VLBI images of the quasars 3C 273 and 3C 345 with dynamic ranges in excess of 3000:1. They trace the jet emission on scales from r about 5 parsecs out to about 200 parsecs. The maps of 3C273 at 18 cm wavelength show a well-collimated one-sided jet with a wavy ridge line; these wiggles exist on size scales ranging from about 1 pc to over 10 kpc. We show that the well-known superluminal flow extends to r about 120 pc. Images of 3C 345 at 6 cm wavelength from data taken in 1989 and 1990 show surprising features not seen in lower dynamic-range maps of this otherwise well-studied quasar: the inner part of the jet shows edge-brightening, which is important for modeling of jet confinement. The jet fades out very abruptly at r about 40 pc, then reappears at about 70 pc; beyond 70 pc, the resumed jet flares and is more diffuse than an extrapolation of the inner jet would predict. This morphology is reminiscent of M 87, and is suggestive of a shock wave.