\begin{table}%t1
\caption{\label{table-I}Molecular observations in comet C/2006~W3 (Christensen).} \vspace*{-1.5mm}
%\centering
\par
\begin{tabular}{lcclclcc}
\hline\hline\noalign{\smallskip}
\phantom{IRAM00}2009 UT date & $\langle r_{\rm h}\rangle $ & $\langle \Delta \rangle $ & Line & Intensity    & Unit &Velocity shift &  Prod. rate\\
\phantom{IRAM00}[mm/dd.dd] & [AU]  & [AU]       &      &        &  & [km~s$^{-1}$]   &  [s$^{-1}$] \\
\hline
PACS\phantom{00}11/8.74--8.82         &   3.35    &     3.70       & H$_2$O(2$_{12}$--1$_{01}$)\tablefootmark{a} &  ${<}2.2\times 10^{-18}$\tablefootmark{a} & W m$^{-2}$  &  --  & ${<}1.4\times10^{28}$\\
\hline
SPIRE\phantom{0}11/6.59--6.68  & 3.34    &  3.65    & H$_2$O(1$_{11}$--0$_{00}$) &  ${<}8\times 10^{-18}$  & W m$^{-2}$ &   --            & ${<}4\times10^{28}$ \\
\hline
Nan\c{c}ay\phantom{0}02/10--04/19 & 3.27 & 3.90  & OH 18 cm   & $-0.016\pm0.003$  &   Jy~km~s$^{-1}$   & $-0.32\pm0.12$  & $3.8\pm0.9\times10^{28}$ \\
\hline
IRAM\phantom{00}09/13.88 & 3.20 & 2.57 & HCN(1--0)  & \phantom{$-$}$0.271\pm0.015$ & K~km~s$^{-1}$\tablefootmark{b}  & $-0.21\pm0.03$ & $1.6\pm0.1\times10^{26}$\\
\phantom{IRAM00}09/13.93 & 3.20 & 2.57  & HCN(3--2)  & \phantom{$-$}$0.961\pm0.140$ & &$-0.15\pm0.06$ & $1.8\pm0.3\times10^{26}$\\
\phantom{IRAM00}09/14.86 & 3.20 & 2.59  & HCN(1--0)  & \phantom{$-$}$0.262\pm0.013$ & &$-0.10\pm0.03$ & $1.6\pm0.1\times10^{26}$\\
\phantom{IRAM00}09/14.93 & 3.20 & 2.59  & HCN(3--2)  & \phantom{$-$}$0.972\pm0.097$ & &$+0.03\pm0.04$ & $1.6\pm0.2\times10^{26}$\\
\phantom{IRAM00}09/14.88 & 3.20 & 2.59  & CO(2--1)   & \phantom{$-$}$0.433\pm0.028$ & &$-0.04\pm0.03$ & $3.9\pm0.3\times10^{28}$ \\
\phantom{IRAM00}09/14.40  & 3.20 & 2.58 &  CH$_3$OH($1_0$--$1_{-1}$E)\tablefootmark{c} & \phantom{$-$}$0.086\pm0.011$ & &$-0.10\pm0.04$ & $1.5\pm0.3\times10^{27}$ \\
\phantom{IRAM00}09/14.93 & 3.20 & 2.59  & H$_2$S($1_{10}$--1$_{01}$)    & \phantom{$-$}$0.311\pm0.031$ & &$-0.05\pm0.04$ & $1.0\pm0.1\times10^{27}$ \\
\phantom{IRAM00}09/14.95 & 3.20 & 2.59  & CS(2--1)   & \phantom{$-$}$0.028\pm0.012$ &               & -- &$0.5\pm0.2\times10^{26}$ \\
\phantom{IRAM00}09/14.95 & 3.20 & 2.59 &  H$_2$CO($3_{12}$--$2_{11}$)   & ${<}0.203$ &   & -- &${<}1\times10^{27}$ \\
\phantom{IRAM00}10/29.71 & 3.32 & 3.48  & HCN(1--0)  & \phantom{$-$}$0.165\pm0.010$ & &\phantom{$-$}$-0.15\pm0.03$ & $1.4\pm0.1\times10^{26}$\\
\phantom{IRAM00}10/29.71 & 3.32 & 3.48  & CO(2--1)   & \phantom{$-$}$0.248\pm0.026$ & &\phantom{$-$}$-0.11\pm0.03$ & $3.0\pm0.3\times10^{28}$ \\
\hline
\end{tabular}\vspace*{-2mm}
\tablefoot{\tablefoottext{a}{3-$\sigma$ upper limit per pixel in the
central $9.4\arcsec \times 9.4\arcsec$~pixel. The upper limit on the
flux per beam is estimated to be $\sim$2 times higher. Upper limits for H$_2$O
2$_{21}$--1$_{10}$, 3$_{13}$--2$_{02}$, 2$_{21}$--2$_{12}$, and
3$_{03}$--2$_{12}$ lines are 4.9, 1.8, 1.0, and 3.9
($\times$10$^{-18}$) W m$^{-2}$ respectively.}
\tablefoottext{b}{For IRAM data, the intensity scale is the main beam brightness temperature.}
\tablefoottext{c}{CH$_3$OH 
$2_0-2_{-1}$E, $3_0-3_{-1}$E, $4_0-4_{-1}$E, $5_0-5_{-1}$E, and
$6_0-6_{-1}$E lines were also observed with line intensities of
$0.083$, $0.062$, $0.049$, $0.043$, and $0.022$ ($\pm0.010$)~K~km~s$^{-1}$, respectively.}}\vspace*{-2mm}
\end{table}