\begin{table}%t1
%\begin{minipage}[t]{\columnwidth}
\par
\caption{Characteristics (mean and root mean square) of the distribution of 
$\sigma_{\epsilon}/\sigma_{\Delta m_{\rm true}}$ for the no shift, under- and 
overestimation scenarios and different assumed errors. The distributions were obtained from $10~000$
  simulations of SNLS-like data sets consisting of 250 SNe~Ia each.}         
% title of Table
\label{tab:std}      % is used to refer this table in the text
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\begin{tabular}{llllllll}          % centered columns (4 columns)
\hline\hline                        % inserts double horizontal lines
% table heading
$\sigma_{\rm int}$ & $\sigma_{\rm err}$  &
\multicolumn{2}{c}{Scenario 1$^a$}& 
\multicolumn{2}{c}{Scenario 2$^b$}& 
\multicolumn{2}{c}{Scenario 3$^c$} \\
(mag) & (mag) & Mean & RMS & Mean & RMS & Mean & RMS \\
%\cline{4-6}
\hline
% inserting body of the table
$0.13$ & Eq.~(\ref{eq:err}) & 0.96 & 0.02 & 0.97 & 0.02 & 0.97 & 0.03
\\
$0.09$ & Eq.~(\ref{eq:err}) & 0.94 & 0.03 & 0.95 & 0.02 & 0.95 & 0.04
\\
$0.09$ & 0 & 0.92 & 0.04 & 0.93 & 0.03 & 0.93 & 0.04 \\
$0.05$ & 0 & 0.80 &0.06 & 0.83 & 0.05 & 0.83 & 0.07 \\
\hline                                             
\end{tabular}
\smallskip
$^a$ No shift in halo mass.\\
$^b$ All halo masses are underestimated  by 50\%.\\
$^c$ All halo masses are overestimated   by 50\%.
\end{table}