\begin{table}%t6
\caption{Parameters of the "best'' PDR~models.}\label{tab:pdr2}
%\begin{center}
\par
\begin{tabular}{c|cc}
\hline
\hline
      &\textbf{Henize~2-10}& \textbf{NGC~253}\\
\hline
      $n$(H)~(cm$^{-3}$)& $8.0\pm 1\times 10^{5}$ & $3.0\pm 0.5 \times 10^{5}$\\
%      \hline
      $\chi$~(on each side) & 20~000 & 20~000$^{a}$\\
%\hline
      $ v^{b}$ (km~s$^{-1}$)& 60 & 187\\
%       \hline
      $FF$ & $1.5\pm 0.5\times 10^{-3}$ & $9.7\pm 4\times 10^{-2}$\\
\hline
\end{tabular}
%\end{center}
\par
$^{a}$ Carral et~al.~(\cite{Carral94}) found for NGC~253 a FUV flux of $2\times 10^{4}~G_{0}$ in units of Habing~(\cite{Habing68}) corresponding to $1.2\times 10^{4}~G_{0}$ in units of Draine~(\cite{Draine78}); compatible with our value.\\
$^{b}$ Deduced from Gaussian fits to line profiles.\\
\end{table}