\begin{table}%t2
%\centering
\par
\caption{Estimates of the \hcn($J=1{-}0$) excitation temperatures and 
the \hcn\ column densities towards selected positions using hyperfine 
structure fits. The coordinates are offsets from the position of 
\mbox{Cha-MMS1a}.
\label{table:texfromhcn}}
\begin{tabular}{rrllll}
\hline \hline
$\Delta\alpha$ & $\Delta\delta$ &
$T_{\rm ex}$&$\tau_{\rm main}$&$\Delta v$&$N({\rm HCN})$\\
($\arcsec$) & ($\arcsec$) & (K) && (km~s$^{-1}$)& (cm$^{-2}$)\\
\hline
\noalign{\smallskip}
 40&  20 &$5.2^{+1.0}_{-0.6}$&$1.1~\pm0.3$ &$0.49\pm0.30$&$4.7\times 10^{12}$\\
--50& --10 &$5.3^{+2.7}_{-1.0}$&$0.9~\pm 0.4$&$0.58\pm0.07$&$4.6\times 10^{12}$\\
 10& --10 &$5.6^{+3.0}_{-1.2}$&$0.7~\pm 0.3$&$0.56\pm0.08$&$3.8\times 10^{12}$\\
 70&  20 &$5.4^{+7.0}_{-1.5}$&$0.5~\pm 0.3$&$0.49\pm0.04$&$2.0\times 10^{12}$\\
\hline
\end{tabular}
\end{table}