\begin{table}%t1
      \caption{\label{Table1}The SDSS DR7 Main DAS (March 2009) sample used and the FoF parameters
      for the flux- and volume-limited group catalogues.}
%\centerline
{
         \begin{tabular}{llcccccccc}
            \hline\hline   
\noalign{\smallskip}
 Sample &  $M_{\rm lim}$ & \multicolumn{2}{c} {$z_{\rm lim}$} &  $N_{\rm gal}$ & $N_{\rm groups}$ & $N_{\rm single}$  & $LL_{r0}$ & $LL_{p0}$ &  \% in groups  \\
     & & & & & & & \mbox{km~ s$^{-1}$} &  $h^{-1}$ Mpc   & \\
          1 & 2 & 3 & 4  & 5 & 6 & 7 & 8 & 9 & 10    \\
            \hline
            \noalign{\smallskip}
 Flux-limited  groups \\ 
DR7 Main   & 17.77 & 0.009 & 0.2  & 583362 & 78800 & 314524 & 250--579 & 0.25--0.58 &  46.1\\
Volume-limited groups\\
DR7-18   &  $-18.0$   & 0.02595 & 0.04590  &    40~665  &     5463  & 24~248 & 250.0 & 0.2500 &  40.4 \\
DR7-19   &  $-19.0$   & 0.02595 & 0.07141  &    94~912  &    12~590  & 58~733 & 306.7 & 0.3067 &  38.1 \\
DR7-20   &  $-20.0$   & 0.02595 & 0.11012  &    148~195  &   18~973  & 96~842 & 409.4 & 0.4094 &  34.7 \\
DR7-21   &  $-21.0$   & 0.02595 & 0.16801  &    103~978  &    9139  & 82~854 & 543.8 & 0.5438 &  20.3 \\
            \hline
         \end{tabular}}
\tablefoot{\small\rm\noindent Columns:
1 -- subsample name; 
2 -- galaxy magnitude limit in $r$-band (apparent for flux-limited groups,
absolute for volume-limited groups); 
3 -- lower redshift limit; 
4 -- higher redshift limit; 
5 -- total number of galaxies $N_{\rm gal}$ in samples; 
6 -- number of groups in samples ($n \geq$  2);
7 -- number of single galaxies;
8 -- FoF linking length in the radial velocity,  for $z=0$; 
9 -- FoF linking length in the projected distance in the sky,
    for $z=0$;
10~$-$~fraction of galaxies in groups ($n \geq$ 2).}
\end{table}