\begin{table}%t1
\caption{\label{cat_cara}Characteristics of the catalogues contributing to the LQAC.}
\par
\small%\centerline
 {
\begin{tabular}{lllrll}
\hline
\hline
Catalogue & Flag & Wavelength & No. & Accuracy & Search \\
 & & & quasars & \arcsec & radius \\
 & & & & & \arcsec \\
\hline
ICRF-Ext2 & A & radio & 717 & 0.001 & 1 \\
VLBA & B & radio & 3 357 & 0.001 & 1 \\
VLA-015 & C & radio & 1 701 & 0.015 & 1 \\
JVAS & D & radio & 2 118 & 0.2 & 1 \\
SDSS & E & optical & 74 868 & 0.2 & 1 \\
2QZ & F & optical & 22 971 & 0.2 & 1 \\
FIRST & G & radio & 969 & 0.5 & 2 \\
VLA+015 & H & radio & 157 & 0.2 & 2 \\
HB & I & optical+radio & 7 245 & 1.5 & 2-5-30$^*$ \\
2MASS & J & infrared & -- & 0.2 & 1 \\
GSC2.3 & K & optical & -- & 0.2 & 1 \\
B1.0 & L & optical & -- & 0.2 & 1 \\
VV06 & M & optical+radio & 85 189 & 1.0 & 2-5-10$^*$ \\
\hline
\end{tabular}}
\medskip
$^*$ Three different search radii have been considered for the cross-identification.
\end{table}