\begin{table}%t6
%\centering
\par
\caption{Estimation of the visual extinction by the 9.7 $\mu$m optical depth, the near-infrared excess and the SED fitting method.\label{table_Av}}
\begin{tabular}[!ht]{llll}
\noalign{\smallskip}
\hline
\hline
\noalign{\smallskip}
                          & \multicolumn{3}{c}{Method}\\
\cline{2-4}\\
\multicolumn{1}{c}{Source}& \multicolumn{1}{c}{"$\tau_{9.7}$''} &
\multicolumn{1}{c}{"$E(H-K)$''} & \multicolumn{1}{c}{"SED fitting''}\\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
\object{LLN 8}  & $>$8   & $<$39 & ...\\
\object{LLN 13} & $>$48  & $<$59 & 60\\
\object{LLN 17} & $>$13  & $<$46 & 40 \\
\object{LLN 19} & $>$22  & $<$56 & 45 \\
\object{LLN 41} & $>$10  & $<$40 & ...\\
\hline
\end{tabular}
\end{table}