\begin{table}%t2
%\centering
\par
\caption {\label{tab:sizes}Rough sizes of the box (from rotation axis to corner) and the
  central stellar disc (radius in kpc) determined on the mass
  distribution of the young population alone. The radius of main linear
  resonances for \FBDY\ and \FBDZ. hILR is the horizontal inner
  Lindblad resonance, vILR the vertical one and hUHR is the horizontal
  ultra harmonic resonance.}
\begin{tabular}{@{}llllll@{}}
\hline \hline
      & 600 & 1000 & 1500 & 2000 \\
      & Myr & Myr  & Myr  & Myr  \\
\hline
Box and disc sizes &     &       &       &    \\
Disc  & 0.27 & 0.43 & 0.50  & 0.50 \\
Boxy  & 0.67 & 1.17 & 1.40  & 1.59 \\
Boxy/disc & 2.48 & 2.69 & 2.80 & 3.18 \\
\hline
Resonance radii of \FBDY &     &       &       &    \\
hILR  & 1.27 & 1.61 & 1.89  & 1.80 \\
vILR  & N/A  & 1.34 & 1.68  & 1.81 \\
hUHR  & 3.57 & 3.82 & 4.21  & 4.00 \\
\hline
Resonance radii of \FBDZ &      &      &       &      \\
hILR  & 1.61 & 2.24 & 2.45  & 2.84 \\
vILR  & N/A  & N/A  & N/A   & 2.95 \\
hUHR  & 4.69 & 5.12 & 5.25  & 5.26 \\
\hline
\end{tabular}
\end{table}