\begin{table}%t1
\caption{\label{tab1}Observed properties of 17~GRBs with known redshift. 
The ten columns give the GRB name, the duration~$T_{90}$ in seconds, the three spectral parameters ($\alpha , \beta$, and $E_0$), 
the gamma-ray fluence~$S_{\rm  \gamma}$ in units of~10$^{-6}$~erg~cm$^{-2}$, 
the spectroscopic redshift~$z$, the pseudo-redshift $\hat{z}$, the ratio $\hat{z}$/$z$, 
and a reference for the spectral parameters.}
$$
\begin{array}{llllllllll}
\hline\hline
\noalign{\smallskip}
{\rm Name} & 
{ T}_{90} & 
{\alpha} & 
{\beta}^{{\it a}} &
{ E}_0 & 
{S}_{\gamma} & 
z & 
\hat{z} & 
\hat{z} / z &
{\rm ref.} \\
     & 
{\rm s}  & 
     &
     &
{\rm keV}  & 
     &
  & 
  &
     &      
     \\
\noalign{\smallskip}
\hline 
\noalign{\smallskip}
 970228              &   80 & -1.54 &  -2.5 &  250 &   11 & 0.695 & 0.94 & 1.36 & 1 \\
 970508              &   20 & -1.71 &  -2.2 &  275 &  1.8 & 0.835 & 0.95 & 1.14 & 1 \\
 971214              &   35 & -0.76 &  -2.7 &  125 &  8.8 &  3.42 & 2.87 & 0.84 & 1 \\
 980613              &   20 & -1.43 &  -2.7 &  163 &  1.0 & 1.096 & 2.19 & 2.00 & 1 \\
 990123              &  100 & -0.89 & -2.45 &  703 &  300 &  1.60 & 2.20 & 1.38 & 1 \\
 990510              &   75 & -1.23 &  -2.7 &  210 &   19 &  1.619 & 1.44 & 0.89 & 1 \\
 990705              &   42 & -1.05 &  -2.2 &  199 &   75 &  0.843 & 0.85 & 1.01 & 1 \\
 990712              &   20 & -1.88 & -2.48 &  545 &  6.5 &   0.43 & 0.31 & 0.73 & 1 \\
 000131              & 96.3 &  -1.2 &  -2.4 &  163 &   26 &    4.5 & 1.35 & 0.30 & 2 \\
 010921              & 24.6 & -1.49 & -2.3 &  206 & 10.2 &   0.45 & 0.68 & 1.51 & 3 \\
 020124              & 78.6 & -1.10 &  -2.3 &  133 &  6.8 &    3.2 & 2.17 & 0.68 & 3 \\
 020813              &   90 & -1.05 &  -2.3 &  223 &  102 &   1.25 & 0.91 & 0.73 & 3 \\
 020903              &  9.8 &  -1.0 &  -2.3 &    3 & 0.09 &   0.25 & 0.26 & 1.03 & 4 \\
 021211              &  3.0 & -.896 &  -2.3 &   52 &  .96 &   1.01 & 0.76 & 0.75 & 5 \\
 030226              & 76.8 & -0.95 &  -2.3 &  103 &  6.4 &   1.98 & 2.35 & 1.19 & 6 \\
 030328              & 140. &  -1.0 &  -2.3 &  110 & 26.9 &   1.52 & 1.15 & 0.76 & 6 \\
 030329              & 22.8 & -1.03 &  -2.26 &  59 &  118 &  0.168 & 0.17 & 0.99 & 7 \\
\noalign{\smallskip}
\hline
\end{array}$$
\end{table}