\begin{table}%t2
\caption{\label{simple_model}Best-fit model parameters and 90\% c.l. errors;  $F_{\rm X}$ is the unabsorbed flux in the 0.1--0.5~keV energy band.}
%\centering
\small
\begin{tabular}{lccccccccc}
\hline\hline
\noalign{\smallskip}
Mod. &$\chi^{2}_{\rm red}$/d.o.f. &$N_{\rm H}$ & $T$ & $R$ &$\alpha$& $Z$  & $F_{\rm X}$ & $F_{\rm bol}$\\
           &  & ($10^{20}~ \mbox{cm}^{-2}$) & ($10^{5}$ K) & ($10^{9}$ cm) & &&($10^{-10}$ $\frac{\rm erg}{\rm cm^{2}~ s}$) &($10^{-10}$ $\frac{\rm erg}{\rm cm^{2} ~s})$\\
\noalign{\smallskip} \hline \noalign{\smallskip}
Blackbody & 0.98/124 &$5.2^{\rm +1.3}_{-1.9}$ & $3.13^{\rm +0.46}_{-0.23}$ & $3.4^{\rm +3.4}_{-2.1}$ & -- & -- & $0.9$ & $1.9$ \\\noalign{\smallskip}
Brems. & 1.10/124 &  $4.1^{\rm +5.2}_{-1.0}$ & $4.87\pm0.46$ &  -- & -- & --& $0.6$ & $12.3$\\\noalign{\smallskip}
Mekal &  0.93/123 & $5.5^{\rm +2.0}_{-1.7}$ & $3.94\pm0.69$ & -- & --& $0.02_{\rm -0.01}^{+0.02}$  & $3.0$ & $86.1$\\\noalign{\smallskip}
Pow. law & 1.69/124 & $\geq$$4.89$ &-- &--& $\geq$$9.4$&--& $\geq$$22.6$ & --\\
 \hline
\end{tabular}
\end{table}