\begin{table}%t2
\caption{\label{tab:30m-info}Observation parameters of the IRAM-30~m observations.}
%\centerline
 {\tiny
\begin{tabular}{lcrlccrclccr}
\hline  \hline\noalign{\smallskip}
Molecule & Transition    & Frequency  & Instrument & \Feff{}  & \Beff{} & Resol. & Resol. & Int. Time & Noise$^{\dagger}$ & Observing & Obs. date \\
         &               & GHz        &            &          &         & arcsec & \kms{} & hours     &   K               & Mode      & \\
\hline   
HCO$^+$  & \Jone{}       &  89.188523 & 30~m/A100   & 0.95     & 0.78    & $27.6''$ & 0.20 & 4.7       & 0.02 & ON-OFF  & 2008 \\
HOC$^+$  & \Jone{}       &  89.487414 & 30~m/A100   & 0.95     & 0.78    & $27.5''$ & 0.20 & 4.7       & 0.02 & ON-OFF  & 2008 \\
CO$^+$   & 2, 5/2--1, 3/2& 236.062578  & 30~m/A230    & 0.91     & 0.52   & $10.4''$ & 0.20 & 4.7       & 0.05  & ON-OFF  & 2008   \\
\HthCOp{}& \Jone{}       &  86.754288 & 30~m/AB100  & 0.95     & 0.78    & $28.4''$ & 0.20 & 2.6       & 0.10 & OTF map & 2006-07 \\
\HthCOp{}& \Jthr{}       & 260.255339 & 30~m/HERA   & 0.90     & 0.46    & $13.5''$ & 0.20 & 5.9       & 0.06 & OTF map & 2006 \\
\DCOp{}  & \Jtwo{}       & 144.077289 & 30~m/CD150  & 0.93     & 0.69    & $18.0''$ & 0.08 & 5.9       & 0.18 & OTF map & 2006 \\
\DCOp{}  & \Jthr{}       & 216.112582 & 30~m/HERA   & 0.90     & 0.52    & $11.4''$ & 0.11 & 1.5       & 0.10 & OTF map & 2006 \\
\hline
\end{tabular}}
\medskip
$^{\dagger}$ The noise (in $T_{\emr{mb}}$ scale)  refers to the channel spacing 
obtained by averaging adjacent channels to the velocity resolution given in the tables.
\end{table}