\begin{table}%t2
%\centering
\par
\caption{Formation rates for each possible GRB progenitor type, for 
$\lambda = 0.5$.             % title of Table
\label{Table:4} }     % is used to refer this table in the text
\begin{tabular}{c c c c}        % centered columns (4 columns)
\hline\hline                 % inserts double horizontal lines
\par
 Scenario & Type & Fate & Birthrate [yr$^{-1}$]\\    % table heading 
\hline                        % inserts single horizontal line
   A & He-shell RLOF      & CO-BH merger & 5.64 $\times$ $10^{-6}$ \\
   B & pre He-shell RLOF  & He-BH merger & 3.83 $\times$ $10^{-5}$ \\
   C & CO + BH            & collapsar?   & 1.39 $\times$ $10^{-7}$ \\      % inserting body of the table
\hline                                   
\end{tabular}
\end{table}