\begin{table}%T1
%\centering
\par
\caption{Observational parameters of the VLA measurements. The rms
noise values are given for total intensity~($I$) and polarized intensity~($I_{\rm P}$). Further explanations are given in the text below.}
\label{tab1}
\begin{tabular}{l|c|c|c|c} \hline\hline
 & \multicolumn{3}{c|}{$\lambda$3.6~cm} &  $\lambda$6.2~cm   \\ \hline
Central frequency [GHz] & \multicolumn{3}{c|}{8.4399} & 4.8851 \\
Bandwidth [MHz] &  \multicolumn{3}{c|}{2~$\times$~50} & 2~$\times$~50   \\
Epoch & \multicolumn{3}{c|}{3/1996} &  7/1983  \\
Time on-source [hr] & \multicolumn{3}{c|}{14}  & 6  \\
Array & \multicolumn{3}{c|}{C}  & C  \\
Phase calibrator & \multicolumn{3}{c|}{1216+487}   & 1216+487  \\
Robust & 0 & 4 & 4 & 5 \\
Beam [arcsec] & 2.4 & 3.3 & 14 & 14 \\
rms ($I$) [$\mu$Jy/b.a.] & 8  & 8 & 70 & 60  \\
rms ($I_{\rm P}$) [$\mu$Jy/b.a.] & -- & 7 & 30  & 55   \\ \hline
\end{tabular}
\end{table}