\begin{table}%t2
%\centering
\par
\caption{Least square fit of the gas fraction versus temperature $T$ (in~keV) 
to the local sample of
X-ray clusters. Uncertainty in the normalization constant is 4--5\%. The
dispersion around the fit is also given in percentage. }
\label{tab2}
\begin{tabular}{lcc} \hline
\hline
 Radius   & Gas fraction  &  Gas fraction   \\
    &  ($\Omega_{\rm m} = 1$)  & ($\Omega_{\rm m} = 0.3$)   \\\hline
 $R_{2000}$      &  $0.061T^{0.31\pm0.06}$ (17\%)         &   $0.063T^{0.32\pm0.06}$ (16\%) \\  
 $R_{1000}$         &   $0.075T^{0.23\pm0.06}$  (17\%)  &   $0.075T^{0.24\pm0.06}$ (17\%)\\  
 Virial     &  $0.090T^{0.14\pm0.07}$  (18.8\%)      &   $0.097T^{0.095\pm0.08}$ (22\%)  \\\hline
\end{tabular}
\end{table}