A high-resolution multi-wavelength study of the jet in 3C 273
  We present HST images at 622 nm and 300 nm of the optical jet in 3C273 and determine the run of the optical spectral index at 0.2" along the jet. We find no evidence for localized acceleration or loss sites, and support for a little-changing spectral shape throughout the jet. We consider this further evidence in favour of a distributed acceleration process. 
S. Jester, H.-J. Roeser, K. Meisenheimer (MPIA), R. Perley (NRAO), S.   Garrington (Jodrell Bank)