\begin{table}%t3
%\centering
\par
\caption{Best-fit spectral parameters for the three pn sub-spectra
 in the 2--10~keV energy range. Column (1): number of the
 corresponding sub-spectrum (the extraction time range is reported in
 Fig.~\ref{fig:SN}). Column~(2): model used. PL:
 power-law; zgauss: Gaussian line ($\sigma$ fixed to 10~eV); AN: narrow
 diskline annulus
($\Delta R=1$~$R_{\rm g}$; other diskline parameters are discussed in
the text, see Sect.~\ref{sec:trs}).
Column (3): power-law index. Column (4): unabsorbed 2--10~keV flux
($\times10^{-12}$~erg~cm$^{-2}$~s$^{-1}$). Column~(5): line
parameters. \label{tab:subspectra}}
\begin{tabular}{llllll}
\hline
\hline
\noalign {\smallskip}                       
 No.   &{\small Model} &  \multicolumn{1}{c}{\small $\Gamma$} &
 $F^{\rm unabs}_{2-10}$     &  \multicolumn{1}{c}{$E_{\rm line}$ (keV)}  & $\chi^{2}$/d.o.f.  \\
      &    &    &   & \multicolumn{1}{c}{$EW$ (eV)} \\
%
\hline
 1 & {\small PL }       &  $1.61\pm0.11$   &  $3.2\pm0.5$  & \multicolumn{1}{c}{ -- }  &  83.8/97  \\
 & \multicolumn{1}{c}{PL+zgauss} & 1.64~$\pm$~0.11 & \multicolumn{1}{c}{
   -- } & 5.47~$\pm$~0.04 & 71.0/95   \\
      &    &    &   & 194~$\pm$~89 \\
\hline
 2 & {\small PL }   &  1.51~$\pm$~0.05   &  3.3~$\pm$~0.2 &
 \multicolumn{1}{c}{ -- }  & 98.8/97  \\
\hline
 3 & {\small PL }  & 1.61~$\pm$~0.06   &  3.1~$\pm$~0.2  & \multicolumn{1}{c}{ -- }  &  117.9/97  \\
 & \multicolumn{1}{l}{PL+zgauss} & 1.62~$\pm$~0.06 & \multicolumn{1}{c}{
   -- } & 6.35~$\pm$~0.05  &  102.5/95 \\
      &    &    &   & 128~$\pm$~53 \\
 & \multicolumn{1}{l}{PL+AN} & 1.64~$\pm$~0.06 &
 \multicolumn{1}{c}{ -- } & 6.40 (f)  &  95.0/93 \\
      &    &    &   & 287~$\pm$~100 \\     
\hline
\end{tabular}
\end{table}