\begin{table}%t1
\caption{\label{magnetic}Known magnetic massive OB~stars and their properties. We note that for a dipole field, the magnetic field strength at the pole ($B_{\rm pol}$) and the equator ($B_{\rm eq}$) are related by $B_{\rm pol}=2~B_{\rm eq}$. }
\small%\centerline
{
\begin{tabular}{llrrrrlll}
\hline
\hline
Name & Spectral Type & $v\sin i$ & \multicolumn{1}{c}{$P_{\rm rot}$} & \multicolumn{1}{c}{$M$}   &
\multicolumn{1}{c}{Inclination} & \multicolumn{1}{c}{$\beta$} & \multicolumn{1}{c}{$B_{\rm pol}$} & Reference\\
 &  & \multicolumn{1}{c}{(km s$^{-1}$)}  &  \multicolumn{1}{c}{(d)}  & \multicolumn{1}{c}{($M_{\odot}$)}  & \multicolumn{1}{c}{(deg.)} & \multicolumn{1}{c}{(deg.)}   &  \multicolumn{1}{c}{(Gauss)} &\\
\hline\noalign{\smallskip}
$\theta^1$Ori C & O4-6V  & 20             & 15.4  &	  45 & $\sim$45  & 42~$\pm$~6  & 1100~$\pm$~100  & \citet{donati:2002}\\
HD 191612       & Of?p   & $<$77          & 538$^{a}$ & $\sim$40 & $\sim$45  & $\sim$45  &  $\sim$1500   & \citet{donati:2006}\\
$\tau$ Sco      & B0.2V  & 5$^{b}$    & 41    &	  15 & $\sim$70  & $\sim$90  & $\sim$500$^{c}$ & \citet{donati:2006b}\\
$\xi^1$ CMa	& B0.5IV & 20     	  & $<$37 &	  14 &  	 &	     & $\sim$500     & \citet{hubrig:2006}\\
$\beta$~Cep	& B1IV   & 27     	  & 12.00 &	  12 & 60~$\pm$~10 & 85~$\pm$~10 & 360~$\pm$~40    & \citet{henrichs:2000a}\\
V2052 Oph       & B1V    & 63     	  & 3.64  &	  10 & 71~$\pm$~10 & 35~$\pm$~17 & 250~$\pm$~190   & \citet{coralie:2003c}\\
$\zeta$ Cas	& B2IV   & 17     	  & 5.37  &	   9 & 18~$\pm$~4  & 80~$\pm$~4  & 340~$\pm$~90    & \citet{coralie:2003a}\\
$\omega$ Ori    & B2IVe  & 172    	  & 1.29  &	   8 & 42~$\pm$~7  & 50~$\pm$~25 & 530~$\pm$~200   & \citet{coralie:2003b}\\
\hline
\end{tabular}}
\smallskip
{$^{{a}}$ To be confirmed}.\\
{$^{{b}}$ \citet{mokiem:2005}}.\\
{$^{{c}}$ Field more complex than dipolar}. 
\end{table}