\begin{table}%t1 \caption{\label{tab1}Positions of the \mbox{X-ray} sources in the field of ACIS-I as labeled in Fig.~\ref{fig2}. The corresponding $1\sigma$ positional errors, signal-to-noise ratios as well as the estimates of source extent are also tabulated.} %\centerline {\small \begin{tabular}{l c c c c c c } \hline\hline\noalign{\smallskip} Source & RA (J2000) & Dec (J2000) & $\delta$~RA & $\delta$~Dec & $S/N^{a}$ & PSFRATIO$^{b}$ \\ \hline & h:m:s & d:m:s & arcsec & arcsec & $\sigma_{G}$ & \\ \hline 1 & 19:54:57.172 & +31:28:36.59 & 0.30 & 0.22 & 13.02 & 1.08 \\ 2 & 19:54:53.728 & +31:32:12.81 & 0.43 & 0.20 & 14.26 & 1.47 \\ 3 & 19:54:52.507 & +31:24:33.74 & 0.70 & 0.28 & 4.71 & 0.80 \\ 4 & 19:54:46.466 & +31:31:26.13 & 0.36 & 0.47 & 6.88 & 2.38 \\ 5 & 19:54:40.352 & +31:23:11.84 & 0.25 & 0.26 & 10.26 & 0.75 \\ 6 & 19:54:37.457 & +31:32:56.14 & 0.54 & 0.33 & 4.71 & 2.19 \\ 7 & 19:54:35.356 & +31:23:49.09 & 0.29 & 0.19 & 9.74 & 0.83 \\ 8 & 19:54:28.210 & +31:32:37.34 & 0.31 & 0.32 & 5.82 & 2.76 \\ 9 & 19:54:24.920 & +31:30:04.42 & 0.24 & 0.16 & 10.87 & 5.02 \\ 10& 19:54:24.745 & +31:28:24.96 & 0.67 & 0.40 & 3.56 & 9.29 \\ 11& 19:54:22.965 & +31:29:02.08 & 0.14 & 0.17 & 21.18 & 6.13 \\ 12& 19:54:21.016 & +31:33:33.80 & 0.13 & 0.12 & 24.81 & 1.35 \\ 13& 19:54:16.717 & +31:32:11.63 & 0.33 & 0.28 & 6.12 & 2.15 \\ 14& 19:54:12.784 & +31:24:30.48 & 0.37 & 0.52 & 8.36 & 1.78 \\ 15& 19:54:10.148 & +31:30:01.07 & 0.51 & 0.37 & 2.67 & 1.99 \\ 16& 19:54:09.741 & +31:24:11.62 & 0.20 & 0.39 & 3.45 & 0.47 \\ 17& 19:54:02.592 & +31:27:46.74 & 0.27 & 0.34 & 4.59 & 1.03 \\ 18& 19:54:00.649 & +31:23:28.01 & 0.26 & 0.34 & 16.53 & 0.95 \\ 19& 19:53:58.504 & +31:26:19.25 & 0.35 & 0.50 & 9.68 & 1.31 \\ 20& 19:53:52.939 & +31:25:13.26 & 0.28 & 0.40 & 15.18 & 0.90 \\ 21& 19:53:52.315 & +31:27:08.97 & 0.34 & 0.40 & 13.01 & 1.22 \\ 22& 19:55:07.125 & +31:30:03.42 & 0.85 & 0.70 & 2.89 & 0.81 \\ 23& 19:55:03.136 & +31:26:12.22 & 0.82 & 0.51 & 3.28 & 0.96 \\ 24& 19:54:57.325 & +31:28:09.59 & 0.55 & 0.37 & 6.97 & 1.36 \\ 25& 19:54:49.830 & +31:26:45.24 & 0.61 & 0.38 & 3.19 & 1.20 \\ 26& 19:54:30.035 & +31:31:52.60 & 0.73 & 0.44 & 4.22 & 5.44 \\ 27& 19:54:20.292 & +31:21:33.27 & 0.53 & 0.54 & 4.96 & 0.85 \\ 28& 19:54:19.929 & +31:22:50.35 & 0.66 & 0.36 & 4.88 & 1.28 \\ 29& 19:54:06.334 & +31:27:18.46 & 0.42 & 0.43 & 4.03 & 1.68 \\ 30& 19:53:58.555 & +31:31:33.96 & 0.45 & 0.60 & 4.12 & 1.19 \\ 31& 19:53:58.106 & +31:32:01.81 & 0.53 & 0.40 & 4.25 & 1.09 \\ 32& 19:53:53.202 & +31:24:43.93 & 0.60 & 0.57 & 4.45 & 0.68 \\ 33& 19:53:47.918 & +31:28:22.49 & 0.81 & 0.60 & 3.66 & 1.12 \\ 34& 19:55:03.855 & +31:29:04.65 & 0.54 & 0.63 & 4.10 & 0.90 \\ 35& 19:54:29.821 & +31:28:34.14 & 0.67 & 0.49 & 3.78 & 10.81 \\ 36& 19:54:15.732 & +31:33:27.84 & 0.50 & 0.42 & 4.38 & 1.56 \\ \hline \end{tabular}} \smallskip $^{a}$~Estimates of source significance in units of Gehrels error: $\sigma_{G} = 1 + \sqrt{C_{B}+0.75}$ where $C_{B}$ is the background counts; $^{b}$~the ratios between the source extents and the estimates of the PSF~sizes. \end{table}