\begin{table}%t2
      \caption{\label{Table3}The first rows of the SDSS DR7
        flux-limited group catalogue described in this paper.}
         \begin{tabular}{ccccccccccc}
            \hline\hline
            \noalign{\smallskip}
         $ {\rm ID}_{\rm gr}$ & $n$ &  RA & Dec & Dist &
        Size$_{\rm sky}$& $ \sigma_R $ &  $\sigma_{V}$&$R_{\rm vir} $ & Weight  & $L_{\rm obs}$   \\
           &  & [deg] & [deg] & [$h^{-1}$ Mpc] & [$h^{-1}$ Mpc] & [$h^{-1}$  Mpc] & [\mbox{km~ s$^{-1}$}]  &  [$h^{-1}$ Mpc] &
             & [$ 10^{10} ~h^{-2} ~L_{\sun} $ ] \\
            \noalign{\smallskip}
          1 & 2 & 3 & 4  & 5 &
        6 & 7 & 8 & 9 & 10 & 11\\
            \hline
            \noalign{\smallskip}
      1  & 3 &   109.822853 &  41.162451 &  83.7400 &  0.0634 & 0.037494 & 131.052963 & 0.050429 &  1.056 &  0.2402961 \\
      2  & 2 &   109.960762 &  41.369118 & 263.6165 &  0.3486 & 0.226603 &  15.567180 & 0.320465 &  1.534 &  1.375062  \\
      3  & 4 &   110.053011 &  41.275907 & 195.5326 &  0.5412 & 0.227071 & 194.728271 & 0.279245 &  1.263 &  1.713846 \\
      4  & 4 &   110.290878 &  41.030225 &  71.1812 &  0.5744 & 0.230941 & 126.573807 & 0.229455 &  1.072 &  0.1092000 \\
      5  & 2 &   110.125167 &  41.206594 & 132.8659 &  0.0448 & 0.030350 &  19.526409 & 0.042921 &  1.115 &  0.3151180 \\
            \hline
         \end{tabular}
   \end{table}