\begin{table}%t4
\caption{Best fit parameters to EPIC~data using a plasma emission
  model built from the MEKAL~code in which the emission measure
  distribution follows a power-law in temperature of the forme
  $EM_{\rm max} \times (T/T_{\rm max})^{\alpha}$.}\label{tab4}
%\centering
\par
\begin{tabular}{c | c c }
\hline
\hline
        & Flares period & Quiescent period \\
\hline
$N_{\rm H}$ (cm$^{-2}$) & 10$^{18}$ (frozen) & 10$^{18}$ (frozen) \\
$Z$ & 0.31 $\pm$ 0.02 & 0.24 $\pm$ 0.08 \\
$kT_{\rm max}$ (keV) & 1.31 $\pm$ 0.05 & 1.08 $\pm$ 0.02 \\
$\alpha$ & 0.84 $\pm$ 0.07 & 1.03 $\pm$ 0.05 \\ 
$EM_{\rm max}$ (10$^{52}$~cm$^{-3}$) & 5.5 $\pm$ 0.5 & 6.6 $\pm$ 0.3 \\
$\chi^{2}$ & 1.09 (259/237 d.o.f.) & 1.45 (487/335 d.o.f.) \\
\hline
\end{tabular}
\end{table}