\begin{table}%t2
\caption{\label{tab_cand}Properties of the INS candidates selected for optical follow-up.}
%\centering
\par
\begin{tabular}{l l l c c c r c c} 
\hline \hline\noalign{\smallskip}
 Source identification & RA & Dec & $b$$^a$ & $\nh^{\rm Gal}$$^b$ & $r_{90}$$^c$ & pn CR$^d$ & Selection & Optical\\
 & (J2000) & (J2000) & (degrees) & (cm$^{-2}$) & (arcsec) & (s$^{-1}$) & region & data$^e$\\
\hline\noalign{\smallskip}
\zersixfiv & 10 46 08.7 &  $-59$ 43 06.1 & $-0.60$  & 1.35~$\times$~10$^{22}$ & 1.33 &  0.060(4)   & II, III, IV & $\star,\diamondsuit$\\ 
\onesixfou & 12 10 17.1 &  $-46$ 46 11.2 & +15.52 & 8.70~$\times$~10$^{20}$ & 2.60 &  0.027(6)   & III         & $\star$\\ 
\throneeig & 01 06 42.4 &  +00 50 31.3 & $-61.79$ & 3.18~$\times$~10$^{20}$ & 3.80 &  0.020(5)   & III         & $\star$\\ 
\thrfoueig & 04 35 53.2 &  $-10$ 26 50.0 & $-34.80$ & 5.80~$\times$~10$^{20}$ & 2.70 &  0.019(3)   & III         & $\ddag$\\ 
\thrfiveig & 03 14 59.9 &  $-29$ 18 15.5 & $-58.42$ & 1.32~$\times$~10$^{20}$ & 2.41 &  0.018(4)   & III         & $\ddag$\\ 
\thrsixfou & 21 40 26.2 &  $-23$ 32 22.3 & $-46.95$ & 3.51~$\times$~10$^{20}$ & 1.90 &  0.0181(20) & III         & $\dag$\\ 
\sixzerfou & 12 59 04.6 &  $-04$ 05 02.3 & +58.73 & 1.81~$\times$~10$^{20}$ & 1.90 &  0.0129(21) & III         & $\dag$\\ 
\sixeigone & 12 50 45.7 &  $-23$ 33 47.7 & +39.31 & 7.37~$\times$~10$^{20}$ & 3.30 &  0.0122(21) & III         & $\dag$\\ 
\hline
\end{tabular}
\smallskip
$^a$ Galactic latitude.\\
$^b$ Total Galactic extinction \citep{dic90}.\\
$^c$ Positional error (90\% confidence level).\\
$^d$ EPIC pn count rate in total energy band (0.2--12~keV).\\
$^e$ Obtained during different observing periods: $^\star$ESO-VLT P79 (pre-imaging), $^\dag$SOAR 2007A, $^\ddag$SOAR 2007B, $^\diamondsuit$SOAR 2008A.
\end{table}