\begin{table}%t2
\caption{Luminosity sub-samples.}\label{lumintable}
%\centering
\small
\par
\begin{tabular}{c c} 
\hline \hline
Luminosity range &  Narrow FeK$\alpha\;EW$ \\
${\rm (erg~s^{-1})}$ & (eV) \\
\hline 
%& \\[-10pt]
$1.0\times10^{42}{-}1.8\times10^{44}$ & $\rm 190^{+40}_{-50}$\\
$1.8\times10^{44}{-}6.1\times10^{44}$ & $\rm 150^{+70}_{-100}$\\
$6.1\times10^{44}{-}6.6\times10^{46}$ & $\rm 50^{+50}_{-40}$ \\
\hline
\end{tabular}
\end{table}