\begin{table}%t3
\caption{\label{tab:comp} Comparison between SN~1993J and SN~2008iz.}
\vspace*{-1.5mm}
%%\centering
\par
%\centerline
{\begin{tabular}{lccc}   
\hline\hline               
Property&&SN~1993J&SN~2008iz \\
\hline
spectral index $\alpha$& &--0.99\tablefootmark{a}&--1.08\tablefootmark{b}\\
$L_{5~{\rm GHz}}$& $[10^{27}$~erg~s$^{-1}$~Hz$^{-1}]$&1.5\tablefootmark{c}&2.5\tablefootmark{d}\\
$t_{\rm peak}$-t$_0$& [days]&180\tablefootmark{c}&$\sim$120\tablefootmark{d}\\
$v_{\rm VLBI}$&[\kms]&14900\tablefootmark{e} & 21200\tablefootmark{b}\\
$L_{\rm X-ray~at~t~\sim~220~days}$& $[10^{38}$ erg~s$^{-1}]$&$\sim$$8$\tablefootmark{f} &$<$15\tablefootmark{b}\\
\hline                                   %inserts single line
\end{tabular}}
\vspace*{-1.5mm}
\tablefoot{References: \tablefoottext{a}{\cite{vanDykWeilerSramek1994};}
\tablefoottext{b}{this work;} \tablefoottext{c}{\cite{WeilervanDykMontes1998}}; \tablefoottext{d}{\cite{MarchiliMartiVidalBrunthaler2009}}; \tablefoottext{e}{\cite{MarcaideAlberdiRos1995};} \tablefoottext{f}{\cite{ZimmermannAschenbach2003}.}}\vspace*{2.2mm}
\end{table}