\begin{table}%t12
\caption{Fits with a finite number of ionization components to the column densities of all elements but iron derived with model~B, assuming solar abundances. The number of ionization components is indicated by~$N$. In the last column we give the significance according to an F-test of the added component.}\label{tab:10}
%\centering
\par
\begin{tabular}{lllll}
\hline  \hline
$N$ & $\chi^2$/d.o.f. & log $\xi$ & log $N_{\rm H}$  & Sign. \\
         &          & 10$^{-9}$ W m & m$^{-2}$     &       \\
         \hline
1        & 147/22   & 1.2       &  25.5            &       \\
2        & 86/20    & 2.45, 1.15 &  26.1, 25.4     & 89  \\
3        & 83/18    & 2.47, 1.17, $-$0.70 & 26.1, 25.4, 23.6 & 53\\
\hline
\end{tabular}
\end{table}