\begin{table}%t3
\caption{\label{tabella3}Magnitudes of VLBL candidates observed by \sw~in the six
different UVOT filters.}
%\centering
\par
\begin{tabular}{cccccccc}
\hline\hline\noalign{\smallskip}
 Source & Date     &      $V$ mag     &      $B$ mag     &     $U$ mag      &    $W1$ mag      &    $M2$ mag      &     $W2$ mag     \\
\hline
\a      & 2006 Jan. 05 & 18.35 $\pm$ 0.08 & 18.93 $\pm$ 0.08 & 18.10 $\pm$ 0.05 & 18.27 $\pm$ 0.05 & 18.32 $\pm$ 0.06 & 18.50 $\pm$ 0.04 \\
        & 2006 Jan. 06 & 18.25 $\pm$ 0.10 & 18.72 $\pm$ 0.12 & 18.04 $\pm$ 0.07 & 18.25 $\pm$ 0.07 & 18.21 $\pm$ 0.08 & 18.37 $\pm$ 0.06 \\
        & 2006 Jan. 07 & 18.26 $\pm$ 0.08 & 18.84 $\pm$ 0.08 & 17.88 $\pm$ 0.05 & 18.26 $\pm$ 0.06 & 18.22 $\pm$ 0.06 & 18.53 $\pm$ 0.05 \\
\hline
\b      & 2006 Jan. 07 & 17.77 $\pm$ 0.07 & 18.28 $\pm$ 0.05 & 17.59 $\pm$ 0.04 & 17.94 $\pm$ 0.05 & 18.01 $\pm$ 0.06 & 18.30 $\pm$ 0.05 \\
        & 2007 Jan. 18 & 18.29 $\pm$ 0.14 & 18.75 $\pm$ 0.10 & 18.03 $\pm$ 0.09 & 18.30 $\pm$ 0.09 &    $>$17.79    & 18.77 $\pm$ 0.09 \\
        & 2008 Jan. 04 &       --        &       --        &       --        &      --         &     --          & 18.49 $\pm$ 0.02 \\
        & 2008 Jan. 14 &       --        &       --        &       --        & 17.91 $\pm$ 0.03 &     --          &       --        \\
        & 2009 Mar. 03 &       --        &       --        &       --        &      --         &     --          & 18.96 $\pm$ 0.02 \\
\hline
\c      & 2007 May 16 &       --        &       --        & 19.16$\pm$0.03 &      --         &     --          &       --        \\  
        & 2008 Oct. 17 & 18.94$\pm$0.07 &       --        & 18.90$\pm$0.05 &      --         &     --          & 19.64$\pm$0.08 \\
\hline
\l      & 2006 Feb. 17 &    $>$19.13    &    $>$19.70    &   $>$19.63     &     $>$20.08   &   $>$20.04     &    $>$20.33    \\  
        & 2006 Mar. 31 &    $>$19.26    &    $>$20.11    &   $>$19.71     &     $>$20.34   &   $>$20.43     &    $>$20.85    \\
\hline
\end{tabular}
\end{table}