\begin{table}%t2
\caption {\label{tab:grid_lc}3C 273 Flux measurements from the GRID instrument. For
the first and third block/week the $\sqrt{T_{\rm S}}$ column provides the
value obtained by the standard processing.} 
%\centering
\par
\begin{tabular}{l | cc | cc | cc | cc }
\hline\hline
Energy & Flux during        & $\sqrt{T_{\rm S}}$ &
Flux during       & $\sqrt{T_{\rm S}}$ & Flux during
& $\sqrt{T_{\rm S}}$ & Flux during            &
$\sqrt{T_{\rm S}}$ \\
range  & observing block 1  &             & observing block 2 &             & observing block~3 &             & observing block 1~+~2~+~3  &             \\
(MeV)  & $(10^{-8} \ \gamma/\rm cm^2/s)$ &  & $(10^{-8} \ \gamma/\rm cm^2/s)$  &  &
$(10^{-8} \ \gamma/\rm cm^2/s)$ &  & $(10^{-8} \ \gamma/\rm cm^2/s)$ &  \\
\hline
$100 \div 200$ & $<$15 & 0.2  & $34_{-10}^{+12}$ & 4.6 & $<$37 & 0.9 & $17 \pm 6$ & 3.8 \\
$>$100         & $<$20 & 1.4  & $33 \pm 11$     & 4.4 & $<$50 & 1.5 & 
$22 \pm 6$ & 4.6 \\
\hline
%\end{tabular*}
\end{tabular}
\end{table}