SIMBAD references

We add 20, 6, and 3.6 cm VLA observations of two wide-angle tails (WATs), 1231+674 and 1433+553, to existing VLA data at 6 and 20 cm in order to study the variations of spectral index as a function of position. We apply the spectral tomography process that we introduced in our analysis of 3C 67, 3C 190, and 3C 449 (Katz-Stone; Katz-Stone & Rudnick). Both spectral tomography and polarization maps indicate that there are two distinct extended components in each source. As in the case of 3C 449, we find that each source has a flat spectrum jet surrounded by a steeper spectrum sheath. The steep components tend to be more highly polarized than the flat components. We discuss a number of possibilities for the dynamics of the jet/sheath systems and the evolution of their relativistic electron populations. Although the exact nature of these two coaxial components is still uncertain, their existence requires new models of jets in FR I sources and may also have implications for the dichotomy between FR I and FR II galaxies.