\begin{table}%t2
\caption{\label{M4par}The fundamental parameters of M4.}
\par
\small%\centerline
 {
\begin{tabular}{p{0.5\linewidth}ll}
\hline
\hline
Parameter      &  Value & Ref. \\
\hline
 ($\alpha$, $\delta$)$_{\rm J2000.0}$ & $(16^{\rm h}23^{\rm m}35.5^{\rm s}, -26^{\circ}31' 31'')$ & 1\\
 ($\ell$, $b$)$_{\rm J2000.0}$        & ($350\fdg97$, $15\fdg97$)              & 1\\
distance                            & 1.7 kpc                              & 2\\
core radius $r_{\rm c}$             & 0.53 pc                                & 3\\
half mass radius $r_{\rm h}$        & 2.3  pc                                & 3\\
tidal radius			    & 21 pc 				   & 3\\	
$\rm [Fe/H]$                        & $-$1.07                                        & 4\\
Present-day Total Mass              & 63~000 $M_\odot$                         & 5\\
Age                                 & 12 Gyr                                 & 6\\
Radial velocity 		    & 70.29 km~s$^{-1}$			   & 7\\
\hline
\end{tabular}}
\medskip
$^{{1}}$ Djorgovski \& Meylan (\cite{Djor93});
$^{{2}}$ Peterson et~al.  (\cite{Peter95}); 
$^{{3}}$ Trager et~al.   (\cite{Trag93});
$^{{4}}$ Marino et~al.   (\cite{Mari08});
$^{{5}}$ Richer et~al.  (\cite{Rich04});
$^{{6}}$ Hansen  et~al.  (\cite{Hans04}); 
$^{{7}}$ this work. 
\end{table}