\begin{table}%t9
\caption{\label{t9}Ammonia column densities derived from the VLA maps.}
%\centerline
{
\begin{tabular}{cccc}
\hline\hline\noalign{\smallskip}
Name & $T_{\rm rot}$\tablefootmark{a} & $N_{\rm 22}$\tablefootmark{a} & $N_{\rm tot}$\tablefootmark{a} \\
     &         (K)      & (cm$^{-2}$)  & (cm$^{-2}$)     \\
\hline
\multicolumn{4}{c}{Extended ammonia emission$^b$} \\
G23.44--0.18 & $\ge$9 & 3--30  $\times$ 10$^{14}$ & 1--8  $\times$ 10$^{16}$ \\
G31.24--0.11 & $\ge$14 & 0.6--45  $\times$ 10$^{14}$ & 0.2--2  $\times$ 10$^{16}$\tablefootmark{b} \\
G32.74--0.07 & $\ge$9 & 0.4--45  $\times$ 10$^{14}$ & 0.2--12  $\times$ 10$^{16}$\tablefootmark{b} \\
G35.03+0.35  & $\ge$6 & 2--30 $\times$  10$^{14}$ & 0.1--18  $\times$ 10$^{17}$ \\
G43.89--0.38 & $\ge$6 & 0.2--41  $\times$ 10$^{14}$ & 0.2--230  $\times$ 10$^{16}$\tablefootmark{b} \\
\hline
\multicolumn{4}{c}{Ammonia cores} \\
G12.22--0.12A  & $\ge$47 & 4--9 $\times$ 10$^{16}$ & 2--4 $\times$ 10$^{17}$ \\
G12.22--0.12B  & $\ge$36 & 2--4 $\times$ 10$^{16}$ & 7--17 $\times$ 10$^{16}$ \\
G12.22--0.12M  & $\ge$29 & 1--5 $\times$ 10$^{16}$ & 8--12 $\times$ 10$^{16}$ \\
G31.28+0.06   & $\ge$25 & 6--26 $\times$ 10$^{15}$ & 4--10 $\times$ 10$^{16}$ \\
G35.20--0.74A  & $\ge$49 & 2--3 $\times$ 10$^{16}$ & 6--12 $\times$ 10$^{16}$ \\
G35.20--0.74B  & $\ge$31 & 2--7 $\times$ 10$^{15}$ & 1--3 $\times$ 10$^{16}$ \\
G48.61+0.02   & $\ge$7 & 1--14 $\times$ 10$^{15}$ & 5--210 $\times$ 10$^{16}$ \\
G75.78+0.34   & $\ge$28 & 3--9 $\times$ 10$^{15}$ & 2--4 $\times$ 10$^{16}$ \\
\hline
\end{tabular}}
\par
\tablefoot{\tablefoottext{a}{Given the low spectral resolution (see Sect. 2.2) of the NH$_3$(3,~3) spectra, we estimated
a lower limit for $T_{\rm rot}$ as the maximum $T_{\rm MB}$ value shown by the (2, 2) and (3, 3)
spectra. As an upper limit we arbitrarily assumed 100 K.} 
\tablefoottext{b}{The column densities derived for G31.24--0.11, G32.74--0.07, and G43.89--0.38 
are very approximative due to no optical depth measurement (see Table 5): in this case
$\tau_{\rm tot}$ = 0.1--1 has been arbitrarily assumed.}}
\end{table}