3C273 HST WFPC2/MERLIN MERLIN 18cm
An archetypical jet visible across the electromagnetic spectrum is
that in 3C273. Comparison of MERLIN 18cm and HST optical images shows
that the optical jet is narrower than its radio counterpart and that
knots in the optical jet in the main correspond to narrow oblique
features within the radio outline. Assuming the optical emission is
incoherent synchrotron the lifetime of the optically emitting
electrons (typically ~1000 yr) is 1000 times shorter than at
radio wavelengths. The optical jet therefore traces the present
location of the active jet whilst the radio emission provides
information on its history for the past 1 Myr.
Bahcall (Princeton) et al., 1995, ApJ, 452, L91