\begin{table}%T2
%\centering
\par
\caption{Power-law parameters of the fitted hard X-ray spectra during phases~II and III. The spectral indices deduced from gyrosynchrotron modelling are also given.}
\label{table_HXS_data}
\begin{tabular}{lll}
   \hline\hline  & 10:17:54 & 10:20:25  \\
   \hline $I_0$ [s$^{-1}$~cm$^{-2}$~keV$^{-1}$] & $1.0\times10^{7}$ & $2.7\times10^{7}$ \\
   $\gamma$ & 3.9 & 4.1 \\
   $\delta_{{\rm X}}$ & 4.9...5.4 & 5.1...5.6 \\
   \hline 
   $\delta_{{\rm r}}$ & $2.3\pm0.1$ & $3.5\pm0.2$ \\
   \hline 
\end{tabular}
\end{table}