\begin{table}%t4
%\centering
\par
\caption{\label{table:4} Bolometric parameters. The last line corresponds to reference values resulting from a mean of the values given in the other lines, weighted by $1/{\sigma}_i$.}        
\small  
\begin{tabular}{c c c c c c c c}        
\hline\hline                 
Data & $A_{\rm 1,bol}$ & $\zeta_1$& $\tau_1$ &$A_{\rm 2,bol}$ &$\zeta_2$ & $\tau_2$&$A_{\rm bol,\ell=0}$  \\
& $\sigma_{\rm A1bol}$ &$\sigma_{\zeta 1}$ & $\sigma_{\tau 1}$ &$\sigma_{\rm A2bol}$ &$\sigma_{\zeta 2}$ & $\sigma_{\tau 2}$&$\sigma_{\rm Abol,\ell=0}$ \\   
set & $\left({{{\rm ppm}^2}\over{\mu{\rm Hz}}}\right)$ & & (s) & $\left({{{\rm ppm}^2}\over{\mu{\rm Hz}}}\right)$ & & (s) & (ppm)\\  
\hline \noalign{\smallskip}  
   SPMb & 0.62 & 8.2 $\times 10^{-3}$& 206 &0.23 & 8.5 $\times 10^{-3}$& 69&2.83  \\     
        & 0.01 & 1.0 $\times 10^{-4}$ &   3 &0.01 & 2.0 $\times 10^{-4}$& 2& 0.16  \\ 
   SPMg & 0.47 & 7.1 $\times 10^{-3}$& 207 &0.16 &7.2 $\times 10^{-3}$ & 67& 2.47  \\
        & 0.01 & 1.0 $\times 10^{-4}$ & 6 &0.01 &  3.0 $\times 10^{-4}$ & 4& 0.19  \\
   SPMr & 0.44 & 6.8 $\times 10^{-3}$ & 210 &0.13& 6.6 $\times 10^{-3}$& 64& 2.14   \\
        & 0.03 & 4.0 $\times 10^{-4}$&  17 &0.02& 1.0 $\times 10^{-3}$ & 14& 0.52   \\
   PMO6 & 0.50 &7.2 $\times 10^{-3}$ & 215& 0.14&6.7 $\times 10^{-3}$ & 70& 2.36  \\
        & 0.02 & 2.0 $\times 10^{-4}$& 9  & 0.02& 5.0 $\times 10^{-4}$& 7& 0.23   \\
   Ref. & 0.52 &7.6 $\times 10^{-3}$ & 208& 0.18&7.6 $\times 10^{-3}$ & 68& 2.53  \\
        & 0.01 & 1.0 $\times 10^{-4}$& 3  & 0.01& 2.0 $\times 10^{-4}$& 2& 0.11   \\
\hline   
\end{tabular}
\end{table}