\begin{table}%t2
\caption{\label{zspec}Overview of the sources included in the LRIS mask.}
%\centerline
 {\small \begin{tabular}{lccllrccl}
\hline\hline
ID & $\alpha$ (J2000.0) & $\delta$ (J2000.0) & $z_{\rm spec}$ & $z_{\rm phot}$ & $F775W$ & $\mu$ (mags) & $z_{\rm class}$ & Features\\
\hline \noalign{\smallskip}
1.1 & 198.77725 & 51.81934& $0.8889\pm0.0003$  & $\rm 0.965^{+0.075}_{-0.240}$ & $22.19\pm0.01$ & $4.78\pm0.22$ & 4 & $[{\rm OII}]$, $[{\rm NeIII}]$, H$\delta$, H$\gamma$\\ 
3.1 & 198.76696 & 51.83205& 3.277 $\pm$0.002  & $\rm 3.35^{+0.052}_{-0.134}$ & $22.69\pm0.02$ & $3.40\pm0.47$  & 4 & $Ly_\alpha$(em), SiIV, SiII\\
3.3 & 198.75824 & 51.82982 & $3.277 \pm0.002$  & $\rm 3.35^{+0.024}_{-0.036}$ & $25.34\pm0.05$ & $1.66\pm0.22$ & 4 & $Ly_\alpha$(em), SiIV, SiII\\
4.2/5.2 & 198.76075 &51.82487 &$1.9082 \pm0.004$ &  $\rm 2.25^{+0.216}_{-0.222}$    & $23.72\pm0.02$ &$2.54\pm0.03$ & 3 & ${\rm CIV}$, SiII, ZnII \\  
6.1 & 198.77984 & 51.82640 & $2.360  \pm0.002$  & $\rm 2.59^{+0.144}_{-0.159}$  & $23.56\pm0.02$ & $1.96\pm0.04$ & 4 & $Ly_\alpha$(em), SiIV, CIV, SiII\\
7.3 & 198.75869 & 51.82814 & $2.983 \pm 0.002$ & $\rm 3.20^{+0.210}_{-0.675}$   & $26.81\pm0.10$ & $1.87\pm0.02$ & 9 & $Ly_\alpha$(em)\\
10.1 & 198.78708 & 51.81424& $2.627 \pm 0.004$ &  $\rm 3.10^{+0.324}_{-0.162}$   & $21.40\pm0.01$ & $2.69\pm0.65$ & 3 &  $Ly_\alpha$(abs), SiIV\\
11.3  & 198.76242 & 51.80954 & $2.627 \pm 0.004$ & $\rm 2.70^{+0.189}_{-0.261}$  & $23.55\pm0.02$ & $1.73\pm0.02$ & 3 &  $Ly_\alpha$(abs), SiIV, SiII\\
15.1 & 198.76284 & 51.81246& $2.355 \pm 0.002$ & $\rm 2.44^{+0.171}_{-0.231}$   & $24.89\pm0.05$ & $2.26\pm0.10$ & 4 &  $Ly_\alpha$(em), CIV\\
15.3 & 198.78825 & 51.82173 & $2.355 \pm0.002$ & $\rm 2.60^{+0.150}_{-0.363}$  & $25.44\pm0.05$ & $1.56\pm0.05$& 4 &  $Ly_\alpha$(em), SiIV, CIV\\
16.1/16.3 & 198.78851 & 51.82096 & $2.810 \pm0.004$ & $\rm 2.75^{+0.171}_{-0.165}$ & $25.52\pm0.06$ & $1.61\pm0.02$& 3 &  $Ly_\alpha$(abs), FeII \\
%\hline
20 & 198.76659 & 51.83626 & $1.279 \pm0.0005$& $\rm 1.10^{+0.125}_{-0.126}$   & $21.86\pm0.01$ & $1.51\pm0.03$& 4 &$[{\rm OII}]$\\
21 & 198.76000 & 51.83451 & $1.279 \pm 0.0005$& $\rm 1.13^{+0.137}_{-0.103}$  & $22.57\pm0.02$ & $1.75\pm0.02$ & 4 & $[{\rm OII}]$\\
23 & 198.75612 & 51.80736 & $5.827 \pm 0.0015$ & $6.0^{+0.42}_{-0.38}$  & $27.20\pm0.30$ & $1.20\pm0.03$ & 9 & $Ly_\alpha$(em)\\
gal2 & 198.78811 & 51.84276 & $0.5632 \pm 0.0004$ & $\rm 0.550^{+0.123}_{-0.140}$  & $20.49\pm0.01$ & $0.29\pm0.01$ & 4 & $[{\rm OII}]$, K, H, MgI, MgII\\
gal4 & 198.76596 & 51.85902 & $3.2269  \pm 0.002$ & $\rm 3.44^{+0.09}_{-0.07}$           & $24.16\pm0.03$& $0.40\pm 0.02$ & 3 & $Ly_\alpha$(abs), SiII, SiIV\\
gal11-a & 198.76772 & 51.79678 &  $2.2864  \pm0.002$ & $\rm 2.56^{+0.235}_{-0.252}$& $22.86\pm0.01$ & $0.85\pm0.02$ & 4 & $Ly_\alpha$(em), SiII, CIV\\
gal12 & 198.77770 & 51.79462 & $2.290  \pm0.002$   & $\rm 2.32^{+0.255}_{-0.698}$     & $25.32\pm0.08$ & $0.83\pm0.03$ & 4 & $Ly_\alpha$(em), CIV, AlIII\\
gal13-b & 198.77518 & 51.78871 & $1.035  \pm0.001$& $\rm 1.05^{+0.108}_{-0.112}$    & $23.45\pm0.03$ & $0.48\pm0.01$ & 4 & $[{\rm OII}]$\\
gal16 & 198.79701 & 51.77606 & $0.3906  \pm0.0005$& $-$                                            & & $0.10\pm0.01$ & 4 & K, H\\
gal17 & 198.79065 & 51.77097 & $1.236  \pm0.0005$& $-$                                              & &$0.27\pm0.02$  & 4 & $[{\rm OII}]$\\
gal18-b & 198.78816 & 51.77364 & $0.5860  \pm0.0005$& $-$                                        & &$0.19\pm0.01$ & 4 & $[{\rm OII}]$, MgII, K, H\\
gal19-a & 198.77100 & 51.76841 & $0.2909  \pm0.0005$& $-$                                        & &$0.01\pm0.01$ & 4 & K, H\\
gal19-b  & 198.77063 & 51.76935 & $0.3622 \pm0.0005$& $-$                                       & &$0.06\pm0.01$ & 4 & $[{\rm OII}]$, K, H\\
%\hline
gal1 & 198.78155 & 51.83971 & $0.1432  \pm0.0005$ & & & & 4 & $[{\rm OII}]$, H$\beta$, $[{\rm OIII}]$ \\
gal3 & 198.77735 & 51.85023 & $0.087  \pm0.0005$ & & & & 4 & $[{\rm OII}]$, K, H, H$\beta$, $[{\rm OIII}]$ \\
gal11-b & 198.76774 & 51.79744 & $0.280\pm0.001$& & & & 4 & $[{\rm OII}]$, H$\beta$, $[{\rm OIII}]$ \\
gal13-a & 198.77540 & 51.78808 & $0.1762 \pm0.0005$& & & & 4 & K, H\\
gal14 &198.78653 & 51.78574 & $0.1011  \pm0.0003$& & & & 4 & $[{\rm OII}]$, H$\beta$, $[{\rm OIII}]$\\
gal18-a &  198.78753 & 51.77299 & $0.2705  \pm0.0005$ & & & & 4 & K, H\\
gal20 & 198.79633 & 51.76602 & $0.2766  \pm0.0005$ & & & & 4 & K, H\\
gal21 & 198.78704 & 51.76265 & $0.2781 \pm0.0005$ & & & & 4 & K, H\\
gal22-a & 198.77246 & 51.75876 & $0.2410 \pm0.0005$& & & & 4 & $[{\rm OII}]$, K, H\\
gal22-b & 198.77236 & 51.76022 & $0.2766 \pm0.0005$& & & & 4 & K, H\\
gal23 & 198.75441 & 51.86258 & $0.1765  \pm0.0004$& & & & 4 & $[{\rm OII}]$, K, H, H$\beta$, $[{\rm OIII}]$ \\
gal24 & 198.75110 & 51.86508 & $0.2683  \pm0.0005$ & & & & 4 & K, H\\
\hline
\end{tabular}}
\medskip
From left to right: identification, astrometric position, spectroscopic 
redshift, photometric redshift estimate, ACS-F775W band photometry when available, magnification in magnitudes, redshift quality class (see Sect.~\ref{zmeasure}), main spectroscopic features.
The mentions (abs) and (em) refer to an Ly$_\alpha$ line in absorption or in emission, respectively.
The first part of the table corresponds to multiply-imaged systems, the second part to 
background sources, the third part to cluster members and foreground sources.
\end{table}