\begin{table}%t6
%\centering
\par
\caption{Projected 0.3--10 keV luminosities of r2-3 and r2-4 ($L_{\rm r2\textrm{-}3}$ and $L_{\rm r2\textrm{-}4}$ respectively) in terms of 10$^{37}$ erg s$^{-1}$. The  PDS type is also listed.\label{lns}}
\begin{tabular}{llll}
\hline\hline
Observation  &$L_{\rm r2\textrm{-}3}$&  $L_{\rm r2\textrm{-}4}$ & Type \\
\hline
x1 & 0 & 3 &  B\\
x3 & 1.7 & 1.6 & A\\
x4 & 5.3 & 6.7 &  A\\
\hline
\end{tabular}
\end{table}