\begin{table}%t2
%\centering
\par
\caption{Parameter of the fits $\log(r_{50})= -0.4\alpha M_r+b$, see Fig.~\ref{fig:ls}.} 
\label{tb:lumsiz}
\begin{tabular}{llll}
\hline \hline
          & C-P04-I         &                  &                  \\  
\hline
          & {\it early non-BCGs} & {\it BCGs}    & {\it early field}    \\
\hline
$\alpha$  & $0.48\pm 0.05$  & $0.55\pm 0.08$   & $0.425\pm 0.008$  \\
$b$       & $-3.5\pm0.3$    & $-4.1\pm0.6 $    & $-3.10\pm 0.07$  \\
\hline
          & {\it late}       &                  & {\it late field}         \\
\hline 
$\alpha$  & $0.4\pm 0.2$ &                     & $0.278\pm 0.005$     \\
$b$       & $-3\pm 1$       &                  & $-1.79\pm 0.04$    \\
\hline %\hline
          & C-K07-I         &                  &                         \\ 
\hline
          & {\it early non-BCGs}     & {\it BCGs} &  {\it early field}       \\
\hline
$\alpha$  & $0.41\pm 0.02$    & $0.55\pm 0.08$ & $0.180\pm 0.003$       \\
$b$       & $-2.9\pm 0.2$     & $-4.2\pm 0.7$   & $-0.91\pm 0.03$     \\
\hline
          & {\it late}         &                 &   {\it late field}         \\
\hline
$\alpha$  & $0.40\pm 0.08$   &                  & $0.30\pm0.01$       \\
$b$       & $-2.8\pm 0.6$     &                 & $-1.88\pm0.08$      \\
\hline
\end{tabular}
\end{table}