\begin{table}%t1
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%\centering
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\caption {\label{beamsize}Summary of beam efficiencies and FWHM beam sizes for all the observations
analysed in this paper.}
\begin{tabular}{lcccccc} 
\hline\hline
\noalign{\smallskip}
Lines & Offset ($\arcsec$) & Frequency (GHz) & Telescope & $\eta$ & beam size ($\arcsec$)&Reference \\ \hline
HC$^{18}$O$^+$(3--2), H$^{13}$C$^{18}$O$^+$(3--2),& (0, 0), (0, --10) & $248{-}267$ & JCMT & 0.69 & 21 & This work \\
H$^{15}$N$^{13}$C(3--2), H$^{15}$NC(3--2) & & & & & &  \\ 
H$^{13}$CO$^+$(3--2), HN$^{13}$C(3--2)&(0, 20), (20, 0), (--20, 0) &  $\sim$$ 260$ & JCMT & 0.69 & 21 & This work \\    
SiO(2--1), HN$^{13}$C(1--0), &(0, 0), (0, --10) & $\sim $90 & IRAM & 0.82 & 28 & JS06 \\ 
H$^{13}$CO$^+$(1--0) & & & & & & \\ 
SiO(3--2) & (0, 0), (0, --10) &$\sim $$130$ & IRAM & 0.74 & 19 & JS06  \\ 
SiO(5--4), HN$^{13}$C(3--2), &(0, 0), (0, --10) &$217{-}260$&IRAM &0.52 & 11  & JS06 \\
H$^{13}$CO$^+$(3--2) & & & & & & \\ 
HN$^{13}$C(4--3), H$^{13}$CO$^+$(4--3) & (0, 0), (0, --10) &$\sim $350& JCMT & 0.63 & 14  & JS06 \\ 
H$^{13}$CO$^+$(1--0), HN$^{13}$C(1--0)& (0, 20), (20, 0), (--20, 0) & $\sim$87 & IRAM & 0.82 & 28 & JS04 \\
\hline
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\end{tabular}
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\end{table}