\begin{table}%t3
%\centering
\par
\caption{Colours of ultracool brown dwarfs.\label{colours}}
\begin{tabular}{lcccc} 
\hline    \hline      
Object&$z'-J$&$J-H$&$J-K$\\
\hline
ULAS0034$~^{1,3}$&$3.90\pm0.06$&--$0.28\pm0.05$&--$0.12\pm0.06$\\
CFBDS0059$~^{2}$&$3.86\pm0.06$&--$0.21\pm0.06$&--$0.67\pm0.06$\\
ULAS1335$~^{1,5}$&$4.14\pm0.10$&--$0.35\pm0.01$&--$0.38\pm0.03$\\
2MASS0939$~^{1,4}$&--&$0.18\pm0.181$&--$0.58\pm0.10$\\
WOLF940B$~^{6}$&$3.99\pm0.13$&--$0.61\pm0.04$&--$0.69\pm0.05$\\
CFBDSIR1458&$3.94\pm0.24$&--$0.46\pm0.13$&--$1.02\pm0.37$\\
CFBDSIR2219&$4.45\pm0.10$&--$0.20\pm0.085$&--\\
CFBDSIR2215&$4.30\pm0.12$&--$0.11\pm0.08$&--\\\hline
\end{tabular}
  \tablebib{$^1$ \citet{Leggett.2009}; $^2$ \citet{Delorme.2008a}
  $^3$ \citet{Warren.2007}; $^4$ \citet{Tinney.2005};
  $^5$ \citet{Burningham.2008}; $^6$~\citet{Burningham.2009}.}\vspace*{3mm}
\end{table}