we find a recombination time for the N-1 component to be about 11 years. This time is an order of magnitude smaller than that required for the jet to leave an observable transverse trail.

For the S-1 source the emission may have a nonthermal component (Rodriguez et al 2005). The density of relativistic electrons, $n_{er}$, and magnetic field, $B$, can be estimated using eqns. (2) and (3) from Garay et al. (1996) $$\left(\frac{B}{\mbox{mG}}\right)=0.50
\left(\frac{S_{\nu}}{\mbox{mJy}}\right)^{2/7}
\left(\frac{\theta_{s}}{\mbox{arcsec}}\right)^{-6/7}
\left(\frac{\nu}{10~\mbox{GHz}}\right)^{1/7}
\left(\frac{D}{\mbox{kpc}}\right)^{-2/7}
\left(\log\frac{E_{max}}{E_{min}}\right)^{2/7},~~~~~~~~~~~~~~~~~~~~~~~~~(12)$$ $$\left(\frac{n_{er}E_{min}}{10^{-9}~\mbox{ergs cm}^{-3}}\right)=3.58
\left(\frac{S_{\nu}}{\mbox{mJy}}\right)
\left(\frac{\theta_{s}}{\mbox{arcsec}}\right)^{-3}
\left(\frac{\nu}{10~\mbox{GHz}}\right)^{1/2}
\left(\frac{D}{\mbox{kpc}}\right)^{-1}
\left(\frac{B}{\mbox{mG}}\right)^{2/7},~~~~~~~~~~~~~~~~~~~~~~~~~(13)$$ where $E_{max}$ and $E_{min}$ are the maximum and minimum energies of the relativistic electrons that we assume are $10^{11}$ and $10^{6}$ eV respectively. For the distance $D=2.9$ kpc and $\theta_s=0.76$ arcsec, we get $B=1.4$ mG and a density of relativistic electrons of $n_{er}=4.6\times10^{-3}$ cm$^{-3}$. The decay time is given by Krolick (1999) as $t_{d}=1.3\times10^{12}\nu^{-1/2}B^{-3/2}$ sec with $\nu$ in Hz and $B$ in G, or $t_{d}(yr) = 0.5B^{-3/2}$ for our frequency. Using the value derived above for $B$ we get $t_{d}=9\times10^4$ yr, which is much too long. A magnetic field of 30 mG would be required to achieve a synchrotron decay time of 100 years.

Franco-Hernández et al. (2008, in preparation) have discovered two linear structures 