\begin{table}%t6
\caption{Parameters of shock models selected, for each category of shocks, as best fits to the H$_2$~emission.}\label{tab:param}
\small%\centerline
{
\begin{tabular}{ccccc}
\hline \hline
 %& & & & \\[-8pt]
Shock type & $v_{{\rm shock}}$  & $n_{{\rm H}}^a$  & Age  & $B^b$ \\
           & (km s$^{-1}$)         & (cm$^{-3}$)         & (yr) & ($\mu$G) \\
\hline 
C   &37 & 10$^4$ & -- & 100 \\
J   &19 & 10$^4$ & -- & 10  \\
C+J &18 & 10$^4$ &  400 & 100\\  
\hline 
\end{tabular}}
\medskip
$^a$ $n_{\rm H}$ = $n$(H) + 2$n$(H$_{2}$). 
$^b$ $B$($\mu$G$) = b[n_{\rm H}$(cm$^{-3}$)]$^{0.5}$, $b=1$ for the C and C+J~shock models and~0.1 for the J~shock model.
\end{table}