\begin{table}%t3
%\begin{center}
\par
\caption{
	Summary of the results of spectral fits with two models:
        cut-off power law and thermal bremsstrahlung, both modified by
        photoelectric absorption.
	The fluxes are computed directly from the source counts and are thus independent of the
	adopted absorption; for comparison the flux of the Crab in the
	20--50~keV energy band is $10^{-8}~{\rm erg~s^{-1}~cm^{-2}}$.
    The errors are at a 90\% confidence level for one parameter of
    interest ($\chi^2_{{\rm min}}+2.7$).
}
\label{tab:fit_res}
\begin{tabular}{l c c c c c c c}
\hline
\hline
parameter                           & L1           & H1            & L2          & H2           & EI           & L3          & H3 \\
\hline
\multicolumn{3}{l}{Cut-off power law} & & & & & \\
$N_{\rm H}\; [10^{22}~ {\rm cm^{-2}}]$& $20\pm8$        & $7.0\pm2.5$   &$19_{-11}^{+15}$ & $N/A$            &      $N/A $             & $N/A$            & $12\pm7$ \\
Photon index                        & $1.5\pm0.4$     & $1.1\pm0.1$ & $1.5\pm0.5$     & $1.4\pm0.2$    & $1.8\pm0.3$      & $1.1\pm0.8$    & $1.2\pm0.2$ \\
$E_{\rm f}$ [keV]                         & $\rm 31_{-8}^{+16}$ & $25.5\pm2.5$  & $\rm 39_{-13}^{+50}$& $\rm 28^{+7}_{-5}$ & $\rm 35_{-10}^{+18}$ & $\rm 25_{-9}^{+31}$ &  $\rm 29^{+5}_{-4}$\\
$\chi^2$/d.o.f.                     & 218/197         & 232/220       & 240/205         & 36/43          &   64/51            & 74/65          & 197/195       \\
\hline
\multicolumn{3}{l}{Bremsstrahlung} & & & & & \\
$N_{\rm H}\; [10^{22}~ {\rm cm^{-2}}]$& $15\pm4   $  & $10.4\pm1.5$  & $15\pm9$    & $N/A$          & $N/A$          & $N/A$         & $13\pm5$ \\
$kT$ [keV]                          & $28\pm2 $    & $33.3\pm1.5$  & $37\pm4$    & $28.5\pm1.0$ & $25.1\pm1.3$ & $35\pm4$    & $32\pm1$\\
$\chi^2$/d.o.f.                     & 220/198      & 240/221       & 240/206     & 36/44        & 68/52        & 62/44       & 198/196       \\
\hline
flux(5--15~keV)$^*$                   & $2.9\pm0.2$  & $7.47\pm0.15$ & $2.3\pm0.5$ & $N/A$          & $N/A$          & $N/A$         & $6.6\pm0.3$   \\
flux(20--50~keV)$^*$                  & $2.9\pm0.1$& $8.2\pm0.1$ & $2.9\pm0.1$ & $8.8\pm0.1$  & $1.96\pm0.04$& $4.0\pm0.2$ & $7.29\pm0.07$ \\
\hline 
\end{tabular}

$^*$ In unity of $10^{-10}~{\rm erg~s^{-1}~cm^{-2}}$.
\end{table}