these two components, with the extended component arising from an aged electron population.

Linear polarization images
--------------------------

### MERLIN images {#section:rm-reference}

Figure \[fig:MERpol\] displays the polarization image made from the MERLIN data.

The majority of the polarized emission is detected in the inner region of the source, in alignment with the compact jet. The polarized intensity peaks in two locations. The brightest one is near the VLBI jet component C, with an integrated polarized intensity of 0.31 Jy and a mean percentage of polarization (defined as $\frac{\Sigma
  \sqrt{Q_i^2+U_i^2}}{\Sigma I_i}$, where $i$ represents the $i$th polarized sub-components) of $m=5.8$ per cent. The secondary one is located between VLBI jet components B and B2, with an integrated polarized intensity of 0.23 Jy and a mean degree of polarization $m=9.5$ per cent. Both of the two peaks show clear deviations from the total intensity peaks in Figure \[fig:MERcont\]. These measurements of polarization structure and fractional polarization are in good agreement with those observed with the VLA at 2-cm wavelength with a similar angular resolution [@Bre84]. The integrated polarized flux density in the whole source is 0.64$\pm$0.05 Jy and the integrated fractional polarization is (4.9$\pm$0.4) per cent. Since the integrated polarized intensity is in 