\begin{table}%t2
\caption{\label{cross_HB}Results of cross-identification between A$-$H and HB.}
\small%\centerline
 {
\begin{tabular}{clrr}
\hline
\hline
Condition & Condition & No. common & Flag \\
 & & quasars & \\
\hline
 $0\arcsec < \rho < 2\arcsec$ & & 1870 & \\
\hline
 $2\arcsec < \rho < 5\arcsec$ & & 227 & \\
 -- & $z_1 > 0$, $z_2 > 0$ & 167	& \\
 -- & $z_1 > 0$, $z_2 > 0$, $\Delta z< 0.1$ & 156 & * \\ 
 -- & $z_1 > 0$, $z_2 > 0$, $\Delta z> 0.1$ & 11 & ! \\ 
 -- & $z_1$ or/and $z_2$ missing & 60 & ! \\ 
\hline
 $5\arcsec < \rho < 30\arcsec$ & & 206 & \\
 -- & $z_1 > 0$, $z_2 > 0$ & 150    & \\
 -- & $z_1 > 0$, $z_2 > 0$, $\Delta z< 0.1$ & 129 & x \\ 
 -- & $z_1 > 0$, $z_2 > 0$, $\Delta z> 0.1$ & 21 & ? \\ 
 -- & $z_1 $ or/and $z_2$ missing  & 56 & ? \\ 
\hline
\end{tabular}}
\medskip
$\Delta z$ stands for the absolute redshift difference between the values given by the two catalogues. The flag is inserted in the final LQAC ASCII file for the user to be aware of the cross identification status.
\end{table}