\begin{table}%t1
%\centering
\par
\caption{Number of peaks detected per square degree in 100 random fields 
with respect to a given threshold.}
\small
\begin{tabular}{cccc}
\hline\hline
Threshold  & 5000 points & 8000 points & 11~000 points  \\
\hline
$\geq$3-$\sigma$  &  $0.7\pm0.8$ & $0.6\pm0.6$   & $1.6\pm0.9$  \\
$\geq$4-$\sigma$  &  $0.1\pm0.2$ & $0.2\pm0.4$   & $0.6\pm0.6$  \\
\hline
\end{tabular}
\label{tab:area2}
\end{table}