\begin{table}%t3
     \caption{Best fit parameters for the nonthermal
                component (\izw\ at $t=12$~Myr).}
        \label{tab:param_izw12}%\centering
\small
\begin{tabular}{@{}cccc@{}}\hline\hline
Model & $l_{\rm nt}\tau_{\rm nt}(5~{\rm~GHz})$ & $\chi^2$
& $\chi_\nu^2$ \\
& (W Hz$^{-1}$ yr) & & \\
\hline
E & $1.1\times 10^{22}$ & 8.2 & 1.6 \\
F & $2.5\times 10^{22}$ & 7.5 & 1.5 \\
G & $1.1\times 10^{22}$ & 8.2 & 1.6 \\
H & $2.5\times 10^{22}$ & 7.6 & 1.5 \\
\hline
\end{tabular}
  \end{table}