\begin{table}%t1
 \caption{X-ray properties of serendipitous sources in the neighborhood of \rx.}\label{tab1}
 \small%\centerline
{
 \begin{tabular}{lcccc}
 \hline\hline
 & & & & \\[-8pt]
Source & \multicolumn{2}{c}{X-ray position} & Positional error$^a$ & Net count rate \\
       & RA (J2000) & Dec (J2000) &   & cts/s \\
  \hline
 \multicolumn{5}{c}{{\bf 1999 observation}}\\
 \hline
 & & & & \\[-8pt]
  A & $08^{\rm h}21^{\rm m}46.339^{\rm s}$ & $-43^{\circ}02'03.73''$ & 0.16$''$ & $(2.51\pm 0.38)\times 10^{-3}$ \\
  B & $08^{\rm h}22^{\rm m}23.924^{\rm s}$ & $-42^{\circ}57'59.29''$ & 0.20$''$ & $(8.42\pm 0.75)\times 10^{-3}$ \\
  \hline
  \multicolumn{5}{c}{{\bf 2005 observation}}\\
  \hline
 & & & & \\[-8pt]
  A & $08^{\rm h}21^{\rm m}46.313^{\rm s}$ & $-43^{\circ}02'03.46''$ & 0.07$''$ & $(3.20\pm 0.30)\times 10^{-3}$\\
  B & $08^{\rm h}22^{\rm m}23.966^{\rm s}$ & $-42^{\circ}57'59.70''$ & 0.18$''$ & $(7.47\pm 0.48)\times 10^{-3}$ \\
    \hline
  \end{tabular}}
  \medskip
$^a$ The positional errors of sources A and B are given by the PSF fitting and the wavelet detection algorithm respectively.
\end{table}