\begin{table}%t1
%\centering
\par
\caption{Best-fit spectral parameters for the two segments of the XRT
observation (WT and PC data), fitted both separately and together. We report
the results either leaving the hydrogen column density as a free parameter, or
freezing it to the Galactic value.\label{tab:XRT}}
\small\begin{tabular}{lccc}\hline\hline
\noalign{\smallskip}
            &$N_{\rm H}$ ($10^{21}$ cm$^{-2}$) &$\Gamma$               &$\chi^2_\nu$ ($\chi^2/$d.o.f.) \\ \hline
            \noalign{\smallskip}
XRT (WT)    &$\rm 1.3^{+0.7}_{-0.6}$               &$\rm 1.92^{+0.27}_{-0.24}$ &1.10 $(29.7/27)$               \\
XRT (PC)    &$\rm 1.4^{+0.8}_{-0.7}$               &$\rm 2.00^{+0.38}_{-0.31}$ &1.05 $(12.6/12)$	       \\
XRT (WT+PC) &$\rm 1.4^{+0.6}_{-0.5}$               &$\rm 1.95^{+0.21}_{-0.21}$ &1.10 $(42.0/38)$	       \\ \noalign{\smallskip}\hline
\noalign{\smallskip}
XRT (WT)    &0.46 (frozen)                     &$1.58\pm0.12$          &1.22 $(34.1/28)$	       \\
XRT (PC)    &0.46 (frozen)                     &$1.58\pm0.14$          &1.41 $(19.1/13)$	       \\
XRT (WT+PC) &0.46 (frozen)                     &$1.61\pm0.10$          &1.20 $(47.0/39)$	       \\ \hline
\end{tabular}
\end{table}