\begin{table}%t1
\caption{Properties of the synchrotron disk in M~31.}\label{tab:syndisk}
%\centerline
{
\begin{tabular}{llllllll}
\hline  \hline
$r$  &$I_6$  &$P_6$  &$\Bt$  &$\Br$
  &$\bt$  &$h_6$  &$h_{20}$ \\
(kpc)  &(mJy/beam)  &(\%)  &($\mu$G)  &($\mu$G)  &($\mu$G)  &(pc)
&(pc)\\
\hline
\pheins 6--8  &3.72 $\pm$ 0.06  & 30 $\pm$ 1  &7.3
  &4.9  &5.4  &220  &290\\
\pheins 8--10         &4.71 $\pm$ 0.05  &33 $\pm$ 1          &7.5
  &5.2  &5.4  &240  &330\\
10--12  &4.19 $\pm$ 0.05  &31 $\pm$ 1  &7.1  &4.9  &5.2  &270  &360\\
12--14  &2.71 $\pm$ 0.05  &35 $\pm$ 1  &6.3  &4.6  &4.3  &290  &390\\
\hline
\end{tabular}}
\bigskip
Notes: $r$ is the radial range, $I_6$ the average non-thermal
radio intensity per beam area at \wav{6} (HPBW~$=3\arcmin$),
$P_6$ the non-thermal degree of polarization at \wav{6} obtained from the average polarized intensity per beam area divided by $I_6$; $h_6$
and $h_{20}$ the exponential scale heights of the synchrotron
emission at \wav{6} and \wav{20}, respectively;
$\Bt$, $\Br$ and $\bt$ are the average equipartition strengths of
the total, regular and turbulent fields, respectively. 
The uncertainty in the derived field strengths is about~20\%.
See Sect.~\ref{sec:nthdisk} for further explanations.
\end{table}