\begin{table}%t2
    \caption{\label{tab:obs:tracks}Observation parameters for the HCO deep integrations shown in
      Fig.~\ref{fig:maps-pdbi}. Associated transitions can be found in
      Table~\ref{tab:spec}.  The RA and Dec offsets are computed with
      reference to $\alpha_{2000} = \rm 05^h40^m54.27^s$, $\delta_{2000} =
      -02\deg 28' 00''$. The positions are also given in the coordinate
      system used to display the maps in Figs.~\ref{fig:maps-pdbi} 
      and~\ref{fig:maps-30m}. In this coordinate system, maps are 
      rotated by 14\deg{} counter-clockwise around the projection center,
      located at $(\delta x,\delta y)$ = $(20'',0'')$, to bring the 
      illuminated star direction in the horizontal direction and the 
      horizontal zero has been set at the PDR edge.}
    %\begin{center}
\par
      {\tiny
        \begin{tabular}{ccc}
          \hline
          \hline\\[-3.2mm]
          Position name & $(\delta$RA, $\delta$Dec) & $(\delta x,\delta y)$ \\ 
                        &         arcsec           &        arcsec         \\[-3.2mm]\\ 
          \hline\\[-3.2mm]
          ``\DCOp{} peak'' & $(20'',22'')$ & $(44.7'',16.5'')$\\[-3.2mm]\\
              ``HCO peak'' & $(-5,0'')$    & $(15.1'', 1.2'')$\\[-3.2mm]\\
          \hline 
        \end{tabular}}
    %\end{center}
\par
    %\begin{center}
\par
      {\tiny
        \begin{tabular}{crlcccrclccc}
          \hline \hline
          Position & Frequency  & Line area$^{a}$ & Instrument & \Feff{} & \Beff{} & Resol. & Resol. & Int. Time$^{b}$ & $T_{\rm sys}$ & Noise   & Obs. date \\
                   & GHz        &   \Kkms{}       &            &         &         & arcsec & \kms{} & h          &    K      &  mK     &   \\
          \hline
          ``\DCOp{} peak'' &  86.670760  & $0.23\pm0.009$ & 30~m/B100 & 0.95 & 0.78 & 28.4 & 0.27 & 0.75/1.5 & 134 & 11 & 2008 \\
                           &  86.708360  & $0.12\pm0.009$ & 30~m/B100 & 0.95 & 0.78 & 28.4 & 0.27 & 0.75/1.5 & 134 & 11 & 2008 \\
                                %
              ``HCO peak'' &  86.670760  & $0.52\pm0.008$ & 30~m/B100 & 0.95 & 0.78 & 28.4 & 0.27 & 0.75/1.5 & 127 & 10 & 2008 \\
                           &  86.708360  & $0.31\pm0.007$ & 30~m/B100 & 0.95 & 0.78 & 28.4 & 0.27 & 0.75/1.5 & 127 & 10 & 2008 \\
%%                            &  86.777460  & $\pm$ & 30~m/AB100 & 0.95 & 0.78 & 29.9 & 0.2 &   & 127 & 66 & 2008 \\
%%                            &  86.805780  & $\pm$ & 30~m/AB100 & 0.95 & 0.78 & 29.9 & 0.2 &   & 127 & 66 & 2008 \\
                                %
                           & 173.3773770 & $0.47\pm0.023$ & 30~m/C150 & 0.93 & 0.65 & 14.2 & 0.067 & 2.0/4.0 & 667 & 66 & 2008 \\
                           & 173.4060816 & $0.26\pm0.018$ & 30~m/C150 & 0.93 & 0.65 & 14.2 & 0.067 & 2.0/4.0 & 667 & 66 & 2008 \\
                           & 173.4430648 & $0.23\pm0.020$ & 30~m/C150 & 0.93 & 0.65 & 14.2 & 0.067 & 2.0/4.0 & 667 & 66 & 2008 \\
                                %
                           & 260.0603290 & $0.16\pm0.019$ & 30~m/C270 & 0.88 & 0.46 & 9.5 & 0.18 & 3.0/6.0 & 740 & 59 & 2008 \\
                           & 260.0821920 & $0.14\pm0.020$ & 30~m/C270 & 0.88 & 0.46 & 9.5 & 0.18 & 3.0/6.0 & 740 & 59 & 2008 \\
                           & 260.1335860 & $0.12\pm0.017$ & 30~m/C270 & 0.88 & 0.46 & 9.5 & 0.18 & 3.0/6.0 & 740 & 59 & 2008 \\
                           & 260.1557690 & $0.06\pm0.016$ & 30~m/C270 & 0.88 & 0.46 & 9.5 & 0.18 & 3.0/6.0 & 740 & 59 & 2008 \\
          \hline
        \end{tabular}}
    %\end{center}
\par
    $^{a}$ Values obtained from Gaussian fits performed on the spectra using 
    the main beam temperature scale.
    $^{b}$ Two values are given for the integration time: the on-source
    time and the telescope time.
    \end{table}