\begin{table}%t2
\caption{\label{cuadro}We compare the X-ray luminosity of RBS~380 with two more clusters of
  galaxies which are optically rich, but have relatively low \mbox{X-ray}
  luminosity. For comparison, we give the bolometric luminosity for~RBS~380~too. }
 %\centering
\par
 \begin{tabular}{lllll}
 \hline \hline\noalign{\smallskip}
   Name & Redshift & Luminosity [erg/s] & band\\
  \noalign{\smallskip}\hline\noalign{\smallskip}
   Cl~0500$-$24   & 0.32 & $5.6\times 10 ^{44}$  & bolometric \\
   Cl~0939$+$4713 & 0.41 & $7.9\times 10 ^{44}$  & bolometric \\
   RBS~380        & 0.52 & $2  \times 10 ^{44}$  & bolometric \\
  \noalign{\smallskip}\hline
 \end{tabular}
\end{table}