\begin{table}
\caption{Data on the 2dFGRS galaxies and groups used}
\label{Tab1}
%\centering
\begin{tabular}{cccccc}
\hline\hline
\noalign{\smallskip}
  Sample & $\Delta$RA & $\Delta$DEC &
  $N_{\rm gal}$&$N_{\rm gr}$&$N_{\rm isol}$\\ 
 & deg & deg & & & \\
\hline
1 & 2 & 3 & 4 & 5 & 6 \\
\hline
\noalign{\smallskip}
  NGP& $75^{\circ}$ &$10^{\circ}$ & 78067   & 10750   & 44134\\
  SGP& $90^{\circ}$&$13.5^{\circ}$ & 106328  & 14465   & 61344\\
\hline
\end{tabular}
\par
\medskip
Columns:
\begin{list}{}{}
\item[1:] the subsample of the 2dFGRS catalogue.
\item[2:] sample width in right ascension (degrees).
\item[3:] sample width in declination (degrees).
\item[4:] total number of galaxies.
\item[5:] number of groups.
\item[6:] number of isolated galaxies.
\end{list}
\end{table}