\begin{table}%T3
\caption{\label{cont_table}Best-fit parameters of the continuum,
obtained from the three-phase~{\it xabs} model simultaneous fit to the \mbox{EPIC-pn}, RGS1 and RGS2~spectra.}
\par
%\centering
\par
\begin{tabular}{c  l l  l l}
\hline \hline\noalign{\smallskip}
 & \multicolumn{2}{c}{Power-law:} & \multicolumn{2}{c}{Modified black body:} \\ 
Obs.~& photon index ($\Gamma$) & normalisation\tablefootmark{a}  & temperature\tablefootmark{b}   & normalisation\tablefootmark{c}  \\
\hline
1 & $1.85 \pm 0.02$ & $3.3 \pm 0.1$ & $189 \pm 2$ & $1.3 \pm 0.1$ \\
\par
2 & $1.82 \pm 0.01$ & $2.8 \pm 0.1$ & $186 \pm 3$ & $1.5 \pm 0.1$ \\
\par
3 & $1.70 \pm 0.02$ & $1.9 \pm 0.1$ & $211 \pm 4$ & $0.5 \pm 0.1$ \\
\par
4 & $1.84 \pm 0.02$ & $2.9 \pm 0.1$ & $189 \pm 2$ & $1.4 \pm 0.1$ \\
\hline
\end{tabular}
\tablefoot  {\tablefoottext{a}{$10^{51}$ photons ${\rm s}^{-1}$ ${\rm keV}^{-1}$ at 1~keV;} 
\tablefoottext{b}{eV;}
\tablefoottext{c}{emitting area times square root of the electron density in $10^{33}$~${\rm cm}^{0.5}$.}}
\end{table}