\begin{table}%t2
\caption{ {\it BeppoSAX} and {\it XMM-Newton} instrumental parameters.}\label{t2}
%\centerline
 {\begin{tabular}{llllllllllllllll}
\hline
\hline
 & \multicolumn{3}{l}{FOV $^a$}   &\  &
        \multicolumn{3}{l}{$E_1-E_2$ $^b$}   &\  &
             \multicolumn{3}{l}{$\Delta E$ $^c$}   &\  &
                  \multicolumn{3}{l}{Sensitivity $^d$}   \\
\hline
\hline
{\it SAX} & LECS & MECS & PDS &  & LECS & MECS & PDS &  & LECS & MECS & PDS &  & LECS & MECS & PDS \\
\cline{2-4}\cline{6-8}\cline{10-12}\cline{14-16}
 & $37^\prime$ & $56^\prime$ & $\sim$80$^\prime$ &   & 0.1--4.5 & 1.6--10 & 13--300 &   & 0.24 & 0.24 & 9 &  & 
                                   10$^{-13}$ & 10$^{-13}$ & $2\times10 ^{-11}$ \\
\hline
{\it XMM}  & MOS1/2 & PN & & & MOS1/2 & PN & & & MOS1/2 & PN & & & MOS1/2 & PN & \\
\cline{2-3}\cline{6-7}\cline{10-11}\cline{14-15} 
 & 30$^{\prime}$ & 30$^{\prime}$ & & & 0.3--10 & 0.5--10 & & & 0.13 & 0.13 & & & $7\times10 ^{-15}$ & 
                   $7\times10 ^{-15}$ &\\ 
\hline
\end{tabular}
}
\par
\smallskip
\par
$^a$ Diameter of the field-of-view.
\par
$^b$ Instrument energy range, in keV.
\par
$^c$ Energy resolution, in keV (at 6 keV for LECS, MECS, MOS1/2, PN; at 60 keV for PDS).
\par
$^d$ Flux from point source after 100 ks exposure (erg cm$^{-2}$ s$^{-1}$).
\end{table}