\begin{table}%T3
\caption{Observational parameters.\label{obs_para}}
%\centerline
 {
\begin{tabular}{lclrclrclr}
\hline\hline
 & \multicolumn{3}{c}{VLA @8.4~GHz} & \multicolumn{3}{c}{VLA @22~GHz} & \multicolumn{3}{c}{VLBA @1.6~GHz} \\
Name & beam & noise & peak & beam & noise & peak & beam & noise & peak \\
     & ($\arcsec \times \arcsec,~ ^\circ$) & \multicolumn{2}{c}{(mJy beam$^{-1}$)} & ($\arcsec \times \arcsec,~ ^\circ$) & \multicolumn{2}{c}{(mJy beam$^{-1}$)} & (mas $\times$ mas, $^\circ$) & \multicolumn{2}{c}{(mJy beam$^{-1}$)} \\ 
\hline
0222+36 & $0.23 \times 0.19, -52$ & 0.19 &  164 & $0.11 \times 0.10, 89$  & 0.17 &  89 & $10.5 \times 4.4, 9 $ & 0.33 & 61.2 \\
0258+35 & $0.22 \times 0.19, -39$ & 0.21 &  126 & $0.12 \times 0.12, 0$   & 0.19 &  56 & $10.4 \times 4.3, 6 $ & 0.40 &  7.5 \\
0648+27 & $0.27 \times 0.24, 65$  & 0.16 & 11.5 & $0.12 \times 0.10, -76$ & 0.19 & 2.3 & $10.6 \times 4.4, 13$ & 0.57 &  4.4 \\
1037+30 & $0.21 \times 0.20, 9$   & 0.09 & 15.9 & $0.08 \times 0.08, 15$  & 0.37 & 2.1 & $10.2 \times 5.1, 22$ & 0.55 &  2.3 \\
1855+37 & $0.27 \times 0.26, 83$  & 0.06 & 0.62 & $0.19 \times 0.17, -88$ & 0.18 & -- & $11.9 \times 5.3, -47$ & 0.38 & -- \\
\hline
\end{tabular}
}
\smallskip
Note -- Observational parameters for VLA and VLBA images in Figs.~\ref{fig0222+36}, \ref{fig0258+35}--\ref{fig1037+30}, \ref{fig1855+37}: beam size, lowest contour (set equal to the $3\sigma$ noise levels) and peak flux densities. 1855+37 is not detected with the VLA at 22~GHz nor at 1.6~GHz with the VLBA.
\end{table}