\begin{table}%t1
\caption{\label{Table:data}Overview of the molecular line transitions used in this research, with indication of the frequency, the upper energy level, the telescope,  the main beam half power beam width (HPBW) and main beam efficienciy~($\eta_{\rm mb}$).} 
\par
%\centering
\par
 {
\begin{tabular}{lcrcccc}
\hline \hline \noalign{\smallskip}
Transition & Frequency & $E_{\rm upper}$ & Telescope & {\it HPBW}  & $\eta_{\rm mb}$ & 
Ref. \\
                  & \multicolumn{1}{c}{[GHz]}     &  \multicolumn{1}{c}{[cm$^{-1}$]} &         & (\arcsec) & 
        & \\
\hline \noalign{\smallskip}
\multicolumn{7}{c}{{\textbf{H$\mathbf{^{12}}$C$\mathbf{^{14}}$N}}} \\ 
3--2 &  265.886& 17.7382 & IRAM &   9.5 & 0.46    & 1\\
4--3 & 354.505 & 29.5633 & APEX & 18 & 0.73 & 2\\
\multicolumn{7}{c}{{\textbf{$\mathbf{^{12}}$C$\mathbf{^{14}}$N}}} \\
$3_{5/2}{-}2_{3/2}$ & 340.032 & 22.6784 & APEX & 18 & 0.73 & 2\\
$3_{7/2}{-}2_{5/2}$ & 340.248 & 22.7039  & APEX & 18 & 0.73 & 2 \\
\multicolumn{7}{c}{{\textbf{$\mathbf{^{12}}$C$\mathbf{^{16}}$O}}} \\
 1--0 &  115.271 & 3.8450 & IRAM &  21  &   0.45 &  5 \\
 1--0 &  115.271 & 3.8450 & OSO &   33 &  0.43  &  6  \\
 2--1 &   230.538 & 11.5350& JCMT & 20  & 0.69   & 1 \\
  2--1 &   230.538 & 11.5350& IRAM & 10.5 & 0.57  & 1 \\
  3--2 & 345.796 & 23.0695& JCMT &  14 & 0.63  & 1\\
  3--2  & 345.796 & 23.0695& APEX &  18 & 0.73  & 1\\
  3--2 & 345.796 & 23.0695 & APEX & 18 & 0.73 & 2 \\
 4--3 & 461.041 & 38.4481& JCMT &  11 & 0.52     &  1\\
  4--3 & 461.041 & 38.4481& APEX & 14 & 0.60 & 2 \\
  7--6 & 806.652 & 107.6424 & APEX & 8 & 0.43 & 2 \\
\multicolumn{7}{c}{{\textbf{$\mathbf{^{13}}$C$\mathbf{^{16}}$O}}}  \\
2--1 & 220.398 & 11.0276 & JCMT & 20 & 0.69 & 1 \\
3--2 & 330.588 & 22.0549 & APEX & 19 & 0.73 & 2 \\
\multicolumn{7}{c}{{\textbf{$\mathbf{^{12}}$C$\mathbf{^{32}}$S}}}  \\
6--5 & 293.912 & 34.3152& APEX & 21 & 0.80 & 2 \\
7--6 & 342.883 & 45.7525& APEX & 18 & 0.73 & 2 \\
\multicolumn{7}{c}{ {\textbf{$\mathbf{^{28}}$Si$\mathbf{^{16}}$O}}} \\
2--1 & 86.846 & 4.3454 & OSO &  42 & 0.55 &4 \\
 5--4 & 217.104 & 21.7261 & SEST & 25 & 0.55 &4 \\
 6--5 & 260.518 & 30.4161  & SEST & 21 & 0.45 &4 \\
 7--6 & 303.990 & 40.5540 & APEX & 20 & 0.80 &2 \\
 8--7 & 345.061 & 52.1397 & APEX & 18 & 0.73 & 2 \\
\multicolumn{7}{c}{ {\textbf{$\mathbf{^{29}}$Si$\mathbf{^{16}}$O}}} \\
7--6 & 300.120 & 40.0461 & APEX & 20 & 0.80 &2 \\
 8--7 & 342.980  & 51.4867 & APEX & 18 & 0.73 & 2 \\
\multicolumn{7}{c}{ {\textbf{$\mathbf{^{30}}$Si$\mathbf{^{16}}$O}}}\\
 7--6 & 296.575 &  39.5730 & APEX & 20 & 0.80 &2 \\
 8--7 & 339.930 & 50.8785 & APEX & 18 & 0.73 & 2 \\
\multicolumn{7}{c}{{\textbf{$\mathbf{^{28}}$Si$\mathbf{^{32}}$S}}} \\
5--4 & 90.771 & 9.0836 & OSO &  42 & 0.60 & 3 \\
 6--5 & 108.924 & 12.7169 & OSO & 35  & 0.50 & 3 \\
 8--7 & 145.226 & 21.7999 & IRAM & 17  & 0.69 & 1 \\
 12--11 & 217.817 & 47.2306 & IRAM &  10.5 & 0.57 & 1 \\
 12--11 & 217.817 & 47.2306 & JCMT & 22  & 0.70 & 3 \\
 16--15& 290.380 & 82.3445 & APEX & 21 & 0.80 & 2 \\
 17--16&308.516  & 92.6355  & APEX & 20 & 0.80 & 2 \\
 19--18 & 344.779 & 115.0319 & APEX & 18 & 0.73 & 2 \\
 19--18 & 344.779 & 115.0319  & JCMT & 14 &  0.63 & 3 \\
 20--19& 362.906 & 127.1372 & APEX & 18 & 0.73 & 2 \\
\multicolumn{7}{c}{ {\textbf{$\mathbf{^{32}}$S$\mathbf{^{16}}$O}}} \\
 $7_7{-}6_6$& 303.927 & 49.3181 & APEX & 20 & 0.80 & 2 \\
 $8_8{-}7_7$ & 344.310 & 60.8030 & APEX & 18 & 0.73 &2  \\
\multicolumn{7}{c}{{\textbf{$\mathbf{^{32}}$S$\mathbf{^{16}}$O$\mathbf{^{16}}$O}}} \\
 $14_{3,11}{-}14_{2,12}$ & 226.300 & 82.6982 & IRAM & 10.5 &0.57 & 1\\  
 $4_{3,1}{-}4_{2,2}$ & 255.553 & 21.7502 & IRAM & 9.5 & 0.46 & 1\\   
 $3_{3,1}{-}3_{2,2}$ & 255.958 & 19.1968 & IRAM & 9.5 & 0.46 & 1\\  
 $5_{3,3}{-}5_{2,4}$ & 256.247 & 24.9425 &IRAM & 9.5 & 0.46 & 1\\  
$3_{3,1}{-}2_{2,0}$ & 313.279 & 19.1968 & APEX & 20 & 0.80 & 2\\  
 $17_{1,17}{-}16_{0,16}$ & 313.660 & 94.5810 & APEX & 20 &   0.80 & 2\\  
 $4_{3,1}{-}3_{2,2}$ &  332.505& 21.7502 & APEX & 19 & 0.73 & 2\\  
 $13_{2,12}{-}12_{1,11}$ &  345.338 & 64.6273 & APEX  & 18 & 0.73 & 2\\  
 $5_{3,3}{-}4_{2,2}$ &   351.257& 24.9425 & APEX & 18 &  0.73 & 2\\  
 $14_{4,10}{-}14_{3,11}$ &   351.873 & 94.4354 & APEX & 18 & 0.73 & 2\\  
\hline
\end{tabular}}\vspace*{2mm}
\tablebib {(1)~new data (see Sect.~\ref{obs_own}); (2)~\citet{Kim2009};   (3)~\citet{Schoier2007AandA...473..871S}; (4)~\citet{GonzalesDelgado2003AandA...411..123G};
(5)~\citet{Teyssier2006AandA...450..167T}; (6)~\citet{Ramstedt2008AandA...487..645R}.}
\end{table}