\begin{table}%t2
        \caption{\label{tab:sky_values}Values of the polarization angle $\alpha_{\rm Sky}$ and
          of the polarization fraction $\Pi$.} 
           %\centering
\par
        \begin{tabular}{ccc}
        \hline\hline\noalign{\smallskip}
          & $\Pi$ (\%) & $\alpha_{\rm Sky}$ ($^\circ$)\\ \hline
          Pulsar position &$13.9\pm0.6$ & $158.1\pm0.5$\\
          $S/N(P)>10$ region &$23.8\pm0.5$ &$152.1 \pm0.3$\\  
          $S/N(P)>3$ region &$15.6\pm0.3$ &$153.7\pm0.4$\\
          seen by a $5'$ beam &$8.8\pm0.2$ &$149.9\pm0.2$\\
          seen by a $10'$ beam&    $7.7\pm0.2$&$148.8\pm0.2$\\
  \hline
        \end{tabular}
\end{table}