\begin{table}%t2
\caption{Spectral fit results. Errors on the fit parameters are 68\% confidence limits, upper limits represent 95\% confidence limits. The 3--10 and 10--25~keV fluxes are unabsorbed.}\label{tab_spectra}
%\centerline
{
\begin{tabular}{lcc}
\hline
\hline
Parameter			& Obs. 1			& Obs. 2 			\\
\hline
$N_{\rm H}$ (atoms cm$^{-2}$) 	& \raisebox{.0ex}[2.5ex][.0ex]{$2.9~10^{22}$} (fixed)	& $2.9~10^{22}$ (fixed) 	\\
$kT_W$ (keV)			& 0.98 $\pm$ 0.02			& 0.92 $\pm$ 0.01			\\
$kT_{\rm e}$ (keV)			& 2.88 $\pm$ 0.06			& 3.04 $\pm$ 0.04			\\
$\tau$			& 7.2 $\pm$ 0.2			& 8.10 $\pm$ 0.15			\\
$R_W$ (km)			& 21.7 $\pm$ 0.9		        & 27.2 $\pm$ 0.7			\\
$E_{{\rm FE}}$ (keV)  		& 6.42 (fixed)			& 6.42 (fixed)			\\
{\it FWHM} (keV)			& 0.78 $\pm$ 0.13			& 0.4$^{+0.2}_{-0.4}$	\\
Fe $EW$ (eV)			& 223				& $<$96				\\
$E_{{\rm edge}}$ (keV)                & 9.1 $\pm$ 0.1                   & 9.1 (fixed)	\\
$\tau_{{\rm edge}}$                   & 0.12 $\pm$ 0.03                 & $<$0.03 \\ 
$F_{3-10}$  (ergs cm$^{-2}$s$^{-1}$) & $1.5 \times 10^{-8}$		& $2.0 \times 10^{-8}$		\\
$F_{10-25}$ (ergs cm$^{-2}$s$^{-1}$) & $1.8 \times 10^{-9}$		& $3.6 \times 10^{-9}$		\\
$\chi^2_{{\rm red}}$ (d.o.f.) 		& 0.6 (40)			& 0.9 (41)			\\	
\hline
\end{tabular}}
\medskip
Fit parameters of the {\tt comptt} model -- $kT_W$: input soft photon (Wien) temperature~-- $kT_{\rm e}$: plasma temperature~-- $\tau$:  plasma optical depth~-- $R_W$: effective Wien radius for the soft seed photons \citep{invest1999}, here derived for an assumed distance of~7~kpc.
\end{table}