\begin{table}%t3
  \caption{\label{WAbest}Best-fit {\it xabs} parameters to the warm absorber of Mrk 279.}
  %\centerline
{\small  
  \begin{tabular}{lccccccc}
    \hline
    \hline
    &  \multicolumn{2}{r}{\it xabs1} & & \multicolumn{2}{r}{\it xabs2} & \\
     & $\log \xi$\tablefootmark{a} & $N_{\rm{H}}$\tablefootmark{b} & $v_{\rm{out}}$\tablefootmark{c} & $\log \xi$\tablefootmark{a} & $N_{\rm{H}}$\tablefootmark{b} & $v_{\rm{out}}$\tablefootmark{c} & $C$-stat/d.o.f. \\ \hline
    $H$ dataset & $0.6\pm0.3$ & $0.8\pm0.5$ & $-100\pm180$ & $2.6\pm0.1$ & $4.1^{\rm +2.7}_{-1.7}$ & $-340\pm180$ & 1642/1453 \\
    $L$ dataset & $1.1\pm0.4$ & $0.8^{\rm +0.8}_{-0.4}$ & $-240^{\rm +145}_{-530}$ & $2.6^{\rm +0.2}_{-1.0}$ & $1.2^{\rm +1.7}_{-1.1}$ & $-435^{\rm +575}_{-225}$ & 1539/1456 \\ 
    $R$ dataset & $0.4\pm0.7$ & $1.5\pm0.5$ & $-320\pm200$ & $2.6\pm0.1$ & $7.2\pm2.3$ & $-550^{\rm +285}_{-105}$ & 1681/1464 \\ 
    Coupled datasets & $0.7\pm0.3$ & $0.7\pm0.3$ & $-200^{\rm +90}_{-270}$ & $2.6\pm0.1$ & $2.7\pm1.1$ & $-370^{\rm +90}_{-130}$ & 4857/4381 \\ 
    \hline 
    \end{tabular}}
    \tablefoot{\tablefoottext{a}{In units of erg s$^{-1}$ cm$^{-2}$}; 
    \tablefoottext{b}{in units of $10^{20}$~cm$^{-2}$}; 
    \tablefoottext{c}{in units of km s$^{-1}$.}
%    \multicolumn{4}{l}{$^b$ In units of $10^{20}$~cm$^{-2}$}\\
%    \multicolumn{4}{l}{$^c$ In units of km s$^{-1}$}\\
}
\end{table}