\begin{table}%t2
\caption{\label{tab2}Spectral fits with a neutral absorber.}
%\centerline
{
\begin{tabular}{lcccccc}
\hline
\hline
model & $N_{\rm H}^a$ 	& $z $	& $\alpha_E^b$ 	&$\alpha_{\rm H}^c$	
& $E_{\rm break}^d$ or $E_{\rm cut}^e$	& $\chi^2$ (d.o.f.) \\ 
\hline
PL	& $0.16\pm0.03$	& 0 FIX  & $0.62\pm0.03$	&		
&		& 145.9/144\\
CUTOFFPL& $\rm 0.13^{+0.05}_{-0.03}$ &0 FIX	& $\rm 0.47^{+0.11}_{-0.07}$& 	
& $\rm 150^{+300}_{-50}$& 131.8/143\\
BKNPL	& $\rm 0.13^{+0.04}_{-0.03}$ & 0 FIX  & $\rm 0.73^{+0.32}_{-0.08}$
& $1.52\pm0.08$ & $\rm 5.0^{+3.0}_{-1.5}$	& 136.1/142\\
Curved  & $\rm 0.13^{+0.03}_{-0.03}$ & 0 FIX  &  $\rm 0.49^{+0.09}_{-0.26}$
& $\rm 3.5^{+3.0}_{-1.8}$  & $\rm 36^{+19}_{-11}$  & 131.8/142\\
\hline
\end{tabular}}
\smallskip
$^a$ In $10^{22}$ cm$^{-2}$. \\
$^b$ Power law energy index, $F(E)\propto E^{-\alpha_E}$.\\
$^c$ Hard power law energy index in the BKNPL and Curved models,
$F(E)\propto E^{-\alpha_E}$ for $E<E_{\rm break}$ and  
$F(E)\propto E^{-\alpha_{\rm H}} \times  E_{\rm break}^{(\alpha_{\rm H}-\alpha_E)}$
for $E>E_{\rm break}$. The Curved model is similar to the BKNPL model
but the two power laws are joined smoothly. \\
$^d$ 
Break energy in keV in the BKNPL and Curved models.\\
$^e$ Exponential cut-off energy in keV in the CUTOFFPL model,
$F(E)\propto E^{-\alpha_E}\times {\rm e}^{E/E_{\rm cut}}$.
\end{table}