\begin{table}%t3
%\centering
\par
\caption{\label{tab3}Comparison of photoionisation models with observations.}
\begin{tabular}{lrrr}
\hline \hline\noalign{\smallskip}
Line &Observed&Model M1 & Model M2\\
\hline %\hline
3727 [O {\sc ii}]               &86.95 $\pm$ 1.45 & 86.58 & 86.21 \\
3869 [Ne {\sc iii}]             &53.05 $\pm$ 0.86 &53.30 & 53.34\\
%4069 [S  {\sc ii}]              &  ...~~~~~~~  &\\
%4076 [S  {\sc ii}]              &  ...~~~~~~~  &\\
4363 [O {\sc iii}]              &14.73 $\pm$ 0.31 & 14.55 & 14.67\\
4471 He {\sc i}                 &4.46 $\pm$ 0.16  &  5.10 & 5.00\\
4658 [Fe {\sc iii}]             &0.85 $\pm$ 0.09  & 0.86 & 0.85\\
4686 He {\sc ii}                &0.93 $\pm$ 0.09  &  0.93 & 0.93\\
4711 [Ar {\sc iv}]              &2.05 $\pm$ 0.29  & 2.76 & 2.09\\
4740 [Ar {\sc iv}]              &1.70 $\pm$ 0.09  & 2.07 & 1.56\\
4861 H$\beta$                   &100.00 $\pm$ 1.51& 100 & 100\\
5007 [O {\sc iii}]              &663.85 $\pm$ 9.54&663.46 & 663.48\\
%5518 [Cl {\sc iii}]             &0.53 $\pm$ 0.05  &0.52 & \\
5755 [N {\sc ii}]               &0.48 $\pm$ 0.13  &  0.15 & 0.14\\
5876 He {\sc i}                 &13.76 $\pm$ 0.23 & 13.26 & 13.14\\
6300 [O {\sc i}]                &2.58 $\pm$ 0.06  & 1.32 & 1.79\\
6312 [S {\sc iii}]              &1.19 $\pm$ 0.04  &1.05 & 0.83\\
6563 H$\alpha$                  &279.49 $\pm$ 4.36&281.13 & 283.11\\
6583 [N {\sc ii}]               &6.08 $\pm$ 0.10  & 6.11 & 6.07\\
6716 [S {\sc ii}]               &5.67 $\pm$ 0.12  &5.68 & 6.54\\
6731 [S {\sc ii}]               &4.41 $\pm$ 0.08  &4.41 & 5.19\\
7136 [Ar {\sc iii}]             &4.13 $\pm$ 0.12  &  2.52 & 2.13\\
7320 [O {\sc ii}] +              &4.18 $\pm$ 0.10  & 3.03 & 2.90\\
9069 [S {\sc iii}]              &8.10 $\pm$ 0.20  &7.88 & 6.86\\ 
$F_{\rm corr}$(H$\beta$)$^a$               &446             & 442 & 464\\
\hline %\\
\end{tabular}
\tablefoot{\tablefoottext{a}{In units 10$^{-16}$~erg~s$^{-1}$~cm$^{-2}$.}} 
\vspace*{2mm}
\end{table}