\begin{table}%t2
 \caption{Spectral parameters as derived from fitting simultaneously the EPIC~PN and MOS phase-averaged spectra, those at pulse maximum and minimum  as well as from  the fits to the  
RGS1 and RGS2 averaged spectra. Quoted errors refer to 90$\%$ confidence level for
 the parameter of  interest.}\label{spectra}
%\begin{center}
{
\begin{tabular}{c c c c c c}
 \hline \hline
 & \multicolumn{3}{c}{EPIC} & \multicolumn{2}{c}{RGS} \\ 
 & Average  &  Pulse maximum     &   Pulse minimum
&  Average  & Average \\
            \hline
${F}_{2-10}^{a}$ & 3.36 $\pm$ 0.02 & 3.84 $\pm$ 0.05 &
2.65 $\pm$ 0.06 & & \\
            \hline
$N_{\rm H}^{b}$    & $\rm 5.9^{+0.7}_{-0.4}$  & 5.2 $\pm$ 0.6 &
$\rm 6.7^{+0.9}_{-1.0}$  & 5.9 (fixed) & $\rm 11.0^{+3.0}_{-2.0}$ \\
$kT_{\rm max}[{\rm keV}]$ & 19 $\pm$ 3   & $\rm 19^{+5}_{-3}$ &
$\rm 18^{+3}_{-2}$ & 19 (fixed) & 19 (fixed)  \\
$\alpha$ & $\rm 0.72^{+0.10}_{-0.08}$ & 0.74 $\pm$ 0.1 & 0.72
(fixed) & 0.72 (fixed) & 0.72 (fixed) \\
$A_{\rm Z}^{c}$ & 0.59 $\pm$ 0.10 & 0.59 (fixed)  & 0.59 (fixed) & 
0.59 (fixed) & 0.59 (fixed) \\
$C_{\rm nor.}^{d}$ $[10^{-3}$] & $\rm 5.1^{+0.4}_{-0.3}$ &$\rm 6.0^{+0.6}_{-0.7}$
& 3.9 $\pm$ 0.1 & 3.9 $\pm$ 0.2 & $\rm 4.6^{+0.4}_{-0.5}$ \\
$EW^{e}$ & $\rm 50^{+34}_{-40}$ & 27($<$80) & 100($<$150) & & \\
\hline
$\chi^2_{\nu}$ ($\chi^2$/d.o.f.) & 1.02 (1082/1058) & 0.91
(561/615) &0.81 (279/344) & 0.96 (200/209) & 0.92 (191/208) \\
\hline    
\end{tabular}}

$^a$ Flux in units of $10^{-12}~\rm erg~cm^{-2}~s^{-1}$ in the 2--10~keV band. \\
$^b$ Column density of the absorber in units of $10^{20}$~cm$^{-2}$. \\
$^c$ Metal abundance in units of the cosmic value (Anders \& Grevesse
\cite{andersgrevesse}). \\
$^d$ Normalization constant of {\sc cemekl } model. \\
$^e$ Equivalent width of the 6.4 keV fluorescent iron line in units 
of~eV.
%\end{center}
\par
\end{table}