\begin{table}%t2
%%\centering
\par
\caption{\label{tab:XRTspec}Spectral analysis of the \textit{Swift}-XRT data.} 
\par
\begin{tabular}{rcccc} 
\hline  \hline \noalign{\smallskip}
Mode & $N_{\rm H}$ & $N_{\rm H}$ & Photon index & $\chi^2$/d.o.f. \\
 & & (rest frame) \\
&   ($10^{21}$~cm$^{-2}$) & ($10^{21}$~cm$^{-2}$) &  & \\
\hline
WT & $\rm 7.2_{-4.6}^{+5.2}$ & -- & $\rm 2.32_{-0.29}^{+0.33}$ & 17.9/17 = 1.05 \\
PC & $\rm 14.1_{-6.0}^{+7.0}$ & -- & $\rm 2.32_{-0.20}^{+0.20}$ & 11.9/17 = 0.70 \\
\hline
WT & $0.23$ & $\rm 3.6_{-3.0}^{+3.6}$ & $\rm 2.28_{-0.17}^{+0.20}$ & 17.7/17 = 1.03 \\
PC & $0.23$ & $\rm 8.3_{-3.7}^{+5.7}$ & $\rm 2.17_{-0.22}^{+0.25}$ & 12.9/17 = 0.76 \\
\hline
\end{tabular}
\tablefoot{The switch from WT to PC mode occurred at $\sim$180~s after the burst. Analysis of data later than about 2000~s gave results comparable to those for the PC mode but with lower statistical significance.}
\end{table}