\begin{table}%t6
 \caption{\label{emission_table}The best-fit parameters of the narrow \ion{O}{vii}~forbidden emission line shown in Fig.~\ref{Oviif}. }
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\par
\begin{tabular}{l l l l l}
\hline \hline\noalign{\smallskip}
Parameter & Obs.~1 & Obs.~2 & Obs.~3 & Obs.~4 \\
\hline
$\lambda_0$\tablefootmark{a} & $22.10$ & $22.10$ & $22.10$ & $22.10$ \\ 
$\lambda$\tablefootmark{b}  & $22.11 \pm 0.06$ & $22.09 \pm 0.04$ & $22.11 \pm 0.02$ & $22.12 \pm 0.08$ \\ 
Flow $v$\tablefootmark{c}  & $+100 \pm 800$  & $-100 \pm 500$ & $+100 \pm 300$ & $+300 \pm 1100$\\
{\it FWHM}\tablefootmark{d} & $<$$0.1$ & $<$$0.1$ & $<$$0.1$ & $<$$0.1$ \\ 
$\sigma_{v}$\tablefootmark{e}  & $<$$600$ & $<$$600$ & $<$$600$ & $<$$600$ \\ 
Line Normalisation\tablefootmark{f} & $1.0 \pm 0.6$ & $1.0 \pm 0.6$ & $1.7 \pm 0.5$ & $0.9 \pm 0.7$ \\ 
\hline
\end{tabular}
\tablefoot {Obtained by adding a Gaussian component to the best-fit \xabs\ model of all four observations. The errors correspond to a $\Delta \chi^{2}$ of~2. \\
\tablefoottext{a}{Theoretical rest frame wavelength in~\AA;} 
\tablefoottext{b}{wavelength in the rest frame of NGC~3516 in~\AA;} 
\tablefoottext{c}{\kms;} 
\tablefoottext{d}{\AA;} 
\tablefoottext{e}{rms velocity in~\kms\ ($\sigma_{v}={{\it FWHM}}/\sqrt{\ln 256}$);} 
\tablefoottext{f}{$10^{49}$~photons~${\rm s}^{-1}$.}}
\end{table}