\begin{table}%t5
\caption{\label{tab5}Integrated optical depths of optically thin lines (see Sects.~4.1.2 and 4.1.3) and resulting excitation temperatures.}
\par
%\centerline
{
\begin{tabular}{ccccccc}
\hline\hline
Species   & \multicolumn{3}{c}{$\int \tau  {\rm d} V$} & \multicolumn{3}{c}{Excitation temperature} \\
& $J=1\leftarrow0$ & $J=2\leftarrow1^a$ & $J=2\leftarrow1/J=1\leftarrow0^a$ &
 $T_{\rm ex, 1-0}^b$ & $T_{\rm ex, 2-1}^{a,b}$ & $T_{\rm ex,LTE}^c$ \\
 &  \multicolumn{2}{c}{(km~s$^{-1}$)}   &  &
  \multicolumn{3}{c}{(K)}                                            \\
\hline
 SiO          & $0.412\pm0.021$ & $1.440\pm0.270$ &  $3.495\pm0.679$ & 5.51 & 5.21 & 23          \\
C$^{34}$S$^a$ & $0.292\pm0.020$ & $0.440\pm0.040$ &  $1.507\pm0.172$ & 5.83 & 5.27 & $7.2\pm0.4$ \\
H$^{13}$CO$^+$& $2.804\pm0.259$ & $2.500\pm0.050$ &  $0.892\pm0.084$ & 5.20 & 5.17 & $3.8\pm0.3$ \\
H$^{13}$CN    & $1.791\pm0.243$ & $2.100\pm0.080$ &  $1.173\pm0.165$ & 5.37 & 5.24 & $4.8\pm0.5$ \\
HN$^{13}$C    & $0.307\pm0.181$ & $0.900\pm0.070$ &  $2.932\pm1.743$ & 5.20 & 5.17 &     --      \\
                 	            &  	          &   	         &      &	   &             \\
CS-NE$^d$     & $0.080\pm0.010$ & $0.280\pm0.080$ &  $3.500\pm1.092$ &  --  &  --  & $11 \pm 3  $  \\
\hline
\end{tabular}}
\medskip
\par
$^a$ In the cases of C$^{34}$S and CS, $J =2 \leftarrow 1$ should be replaced by $J =4 \leftarrow3$. With the exception of the SiO $J =2 \leftarrow 1$ line (Fig.~\ref{fig3}), the $J =2 \leftarrow 1$ and $4\leftarrow3$ data were taken from Muller et~al. (\cite{muller06}). 
$^b$ LVG excitation temperatures of optically thin lines with $T_{\rm kin} = 80$~K, $T_{\rm CMB} = 5.14$~K, and $n$(H$_2) = 2000$~cm$^{-3}$.
$^c$ Excitation temperatures under conditions of Local Thermodynamical Equilibrium (LTE). For the uncertainty in the estimate from SiO (this includes so far unpublished SiO $J=4$--3 data), see Sect.~4.1.2.
$^d$ CS absorption toward the north-eastern continuum component, displaced from the main absorption line by --147~km~s$^{-1}$. Since no spatial density has been derived for this feature, Cols.~5 and 6 are left empty.
\end{table}