\begin{table}%tA.1
\caption{Slope of the envelope of the log~$L_{{\rm H}\alpha} - \log~\sigma_{\rm nt}$~relation for the \hii~regions of NGC~3359 from \hii~region catalogues obtained using different criteria to estimate the \hii~region  cut-off isophote (Col.~1). The slopes (Cols.~2 and~4) have been obtained with the procedure described in Sect.~6.2, and each value represents the median value of
the slopes obtained by stepping the starting luminosity in the
luminosity bins by~0.01~dex. Columns~2 and~4 show the median value when taking into account only \hii~regions with luminosities greater than  log~$L_{\scriptsize\ha}>$ 38.4 and~38.8 (in~erg~s\me) respectively. The standard deviation of each set of slopes is given in Cols.~3 and~5. Column~6 shows the completeness limit of the \hii~region catalogue obtained for each  cut-off isophote criterion.
The symbol "--'' means that there are not enough points to fit an envelope in that case. }\label{apen_tab_3359}
%\centering
\par
\begin{tabular}{c|c c|c c|c}
\hline
\hline
Cut-off &  \multicolumn{2}{|c|}{\small for log~$L_{{\rm H}\alpha}>38.4$} & \multicolumn{2}{|c|}{\small for log~$L_{{\rm H}\alpha}>38.8$ }&Complet.  \\
isophote &  slope & stdev & slope & stdev &limit \\
\hline
$I_{\rm peak}/e$   & 1.18 & 0.08&1.2 &0.2 & 37.4 \\
0.5$I_{\rm peak}$  & 1.2 & 0.2 & -- & --  & 37.4 \\
3 rms       & 1.4 & 0.3 &1.4 & 0.3 & 37.1 \\
5 rms       & 1.5 & 0.2 &1.4 & 0.3 & 37.2 \\
7 rms       & 1.5 & 0.2 &1.4 & 0.3 & 37.4 \\
\hline
\end{tabular}
\end{table}