\begin{table}%t2
 %\centering
\par
 \caption{\label{table_detecthocn}
 Observed transitions of cyanic acid, HOCN, toward Sgr~B2.}
\par
 \vspace*{0.0ex}
 \begin{tabular}{lcrcrrrl}
\hline\hline\noalign{\smallskip}
 \multicolumn{1}{c}{Source\tablefootmark{a}} & \multicolumn{1}{c}{Transition} & \multicolumn{1}{c}{Frequency\tablefootmark{b}} & \multicolumn{1}{c}{$\delta f$\tablefootmark{c}} & \multicolumn{1}{c}{$\sigma$\tablefootmark{d}} & \multicolumn{1}{c}{$I${\tablefootmark{e}}\hspace*{-1.5mm}$_{{\rm obs}}$} & \multicolumn{1}{c}{$I$\tablefootmark{e}\hspace*{-1.5mm}$_{{\rm HOCN}}$} & \multicolumn{1}{c}{Comments} \\ 
  & & \multicolumn{1}{c}{\scriptsize (MHz)} & \multicolumn{1}{c}{\scriptsize (MHz)} & \multicolumn{1}{c}{\scriptsize (mK)} & \multicolumn{1}{c}{\scriptsize (K~km~s$^{-1}$)} & \multicolumn{1}{c}{\scriptsize (K~km~s$^{-1}$)} & \\ 
 \multicolumn{1}{c}{(1)} & \multicolumn{1}{c}{(2)} & \multicolumn{1}{c}{(3)} & \multicolumn{1}{c}{(4)} & \multicolumn{1}{c}{(5)} & \multicolumn{1}{c}{(6)} & \multicolumn{1}{c}{(7)} & \multicolumn{1}{c}{(8)} \\ 
 \hline 
 (20$^{\prime\prime}$,~100$^{\prime\prime}$) & 4$_{0,4}$--3$_{0,3}$ &   83~900.572 & 0.31 &   25 &        10.19(15) &        7.89 & no blend
 \\ 
 & 5$_{0,5}$--4$_{0,4}$ &  1~04~874.679 & 0.31 &   19 &         7.38(11) &        7.60 & no blend
 \\ 
 & 7$_{0,7}$--6$_{0,6}$ &  1~46~820.687 & 0.31 &   29 &         3.59(13) &        3.66 & no blend
 \\ 
 & 8$_{0,8}$--7$_{0,7}$ &  1~67~792.311 & 0.31 &   40 &         2.94(17) &        1.94 & weak detection
 \\ 
 Sgr B2(M) & 4$_{0,4}$--3$_{0,3}$ &   83~900.572 & 0.31 &    8 &         2.13(05) &        1.67 & no blend
 \\ 
 & 5$_{0,5}$--4$_{0,4}$ &  1~04~874.679 & 0.31 &   10 &         2.67(05) &        2.20 & partial blend with $^{13}$CH$_3$CH$_2$CN + U-line?
 \\ 
 & 7$_{0,7}$--6$_{0,6}$ &  1~46~820.687 & 0.31 &   18 &         4.50(08) &        2.90 & partial blend with U-line?
 \\ 
 & 8$_{0,8}$--7$_{0,7}$ &  1~67~792.311 & 0.31 &   43 &         6.56(17) &        3.65 & partial blend with U-line?
 \\ 
 Sgr B2(N) & 4$_{0,4}$--3$_{0,3}$ &   83~900.572 & 0.31 &    9 &         4.66(05) &        3.74 & weak blend with CH$_3$CH$_3$CO
 \\ 
 & 5$_{0,5}$--4$_{0,4}$ &  1~04~874.679 & 0.31 &   10 &        13.98(05) &        5.05 & strong blend with C$_2$H$_3$CN, $v_{11} = 1/v_{15} = 1$ and $^{13}$CH$_3$CH$_2$CN
 \\ 
 & 7$_{0,7}$--6$_{0,6}$ &  1~46~820.687 & 0.31 &   17 &        12.01(08) &        6.89 & blend with U-lines
 \\ 
 & 8$_{0,8}$--7$_{0,7}$ &  1~67~792.311 & 0.31 &   42 &        16.57(18) &        8.66 & blend with H$^{13}$CCCN, $v_6=1$ and U-line
 \\ 
 Sgr B2(S) & 7$_{0,7}$--6$_{0,6}$ &  1~46~820.687 & 4.00 &   21 &         5.03(39) &        3.68 & no blend
 \\ 
 & 8$_{0,8}$--7$_{0,7}$ &  1~67~792.311 & 4.00 &   20 &         0.70(32) &        1.60 & uncertain detection
 \\ 
 (20$^{\prime\prime}$,~$-$180$^{\prime\prime}$) & 7$_{0,7}$--6$_{0,6}$ &  1~46~820.687 & 4.00 &   29 &         1.76(53) &        1.93 & uncertain detection
 \\ 
 & 8$_{0,8}$--7$_{0,7}$ &  1~67~792.311 & 4.00 &   24 &         0.03(38) &        1.51 & uncertain detection
 \\ 
  ($-$40$^{\prime\prime}$,~0$^{\prime\prime}$) & 7$_{0,7}$--6$_{0,6}$ &  1~46~820.687 & 4.00 &   26 &         4.76(61) &        4.55 & no blend
 \\ 
 & 8$_{0,8}$--7$_{0,7}$ &  1~67~792.311 & 4.00 &   36 &         5.17(73) &        4.13 & uncertain detection
  \\ 
 \hline
 \end{tabular}
 \tablefoot{
 \tablefoottext{a}{The J2000 equatorial offsets are given with respect to Sgr~B2(M).}
 \tablefoottext{b}{Laboratory rest frequencies were taken from \citep{BGM2009b}.}
 \tablefoottext{c}{Channel width.}
 \tablefoottext{d}{Measured rms noise level in $T_{{\rm mb}}$ scale.}
 \tablefoottext{e}{Integrated intensity in $T_{{\rm mb}}$ scale for the observed spectrum (Col.~6) and the model of cyanic acid (Col.~7). The integration limits are marked in Figs.~\ref{fig_M}--\ref{fig_offsetpositions} by vertical dotted lines. The uncertainty in Col.~6 is given in parentheses in units of the last digit and is purely statistical.}}\vspace*{2mm}
 \end{table}