\begin{table}%t2
\caption{\label{tab:timing}The relative average runtime per photon  package for the\protect various models.}
%\centering
\small
\begin{tabular}{lccc}
\hline \hline
$M_{\rm dust}$	& \multicolumn{3}{c}{Relative runtime per photon package}\\
$\left[M_{\odot}\right]$			& without MRW	& \multicolumn{2}{c}{with MRW} \\
					&			& $\gamma=1$		& $\gamma=10$ \\
\hline
&&& \\[-8pt]
$10^{-6}$			& 1		& 0.73			& 0.73 \\
$10^{-3}$			& 10.2	& 1.27			& 2.05 \\
$10^{-2}$			& 58.6	& 1.82			& 5.23 \\
\hline
\end{tabular}
\end{table}