\begin{table}%f6 \caption{\label{tab6}Radial velocities (see Sect.~4.2). Uncertainties in the frequencies are small relative to those of the velocities, which were obtained by Gaussian fits$^{a}$.} \par %\centerline { \begin{tabular}{cccc} \hline \hline Species & Transition & Rest & $V_{\rm LSR}$ \\ & & Frequency (GHz) & (km~s$^{-1}$) \\ \hline NH$_3$ & ($J$,~$K$) = (1, 1) & 23.694496 & 9.0~(0.1) \\ & & & 8.6~(0.5) \\ & (2, 2) & 23.722633 & 7.4~(0.2) \\ & & & 10.5~(0.4) \\ & (3, 3) & 23.870130 & 8.6~(0.1) \\ & (4, 4) & 24.139416 & 8.4~(0.2) \\ & & & 9.1~(0.7) \\ & (5, 5) & 24.532989 & 8.2~(0.3) \\ & & & 8.7~(0.5) \\ & (6, 6) & 25.056025 & 8.1~(0.2) \\ & & & 8.5~(0.6) \\ & (7, 7) & 25.715182 & 10.9~(0.4) \\ & (8, 9) & 27.477943 & 8.8~(0.7) \\ & (10, 10) & 28.604737 & 10.2~(2.0) \\ HC$_3$N & $J$ = $ 3\leftarrow2$ & 27.294289 & 9.0~(0.4) \\ & $ 4\leftarrow3$ & 36.392324 & 8.2~(0.3) \\ & $ 5\leftarrow4$ & 45.490314 & 8.0~(1.0) \\ & $ 6\leftarrow5$ & 54.588247 & 7.7~(0.3) \\ & $ 7\leftarrow6$ & 63.686052 & 10.0~(0.4) \\ & & & \\ SiO & $ 1\leftarrow0$ & 43.423846 & 9.8~(0.7) \\ SiO & $ 2\leftarrow1$ & 86.847010 & 8.9~(1.8) \\ C$^{34}$S & $ 1\leftarrow0$ & 48.206946 & 9.8~(0.6) \\ H$^{13}$CO$^+$& $ 1\leftarrow0$ & 86.754288 & 9.7~(0.7) \\ H$^{13}$CN & $ 1\leftarrow0$ & 86.339922 & 8.8~(1.5) \\ HN$^{13}$C & $ 1\leftarrow0$ & 87.090873 & 7.4~(1.3) \\ \hline \end{tabular}} \medskip \par $^a$ Frequencies were taken from the JPL catalog (NH$_3$), the Cologne Database for Molecular Spectroscopy (HC$_3$N), and the line list of Lovas (other species). NH$_3$ transitions with two $V_{\rm LSR}$ values were measured twice (see Henkel et~al.~\cite{henkel08}). \end{table}