\begin{table}%t3
\caption{Results for the nucleus of NGC~253.}\label{tab:obs2}
\par
%\begin{center}
\par
\begin{tabular}{c|cccccc}
\hline\hline
\textbf{NGC~253}&&&&&&\\
\hline
Transition & Freq & Beam size & $\int(T_{\rm mb}{\rm d}v)$ & Intensity & Flux & References$^{a}$\\
&(GHz) & ($\arcsec$) & (K~km~s$^{-1}$) & (W~m$^{-2}$~sr$^{-1}$) & (W~m$^{-2}$) &\\
\hline
CI($^{3}$P$_{1}$--$^{3}$P$_{0}$) & 492.162 & 10.20 & $575.0 \pm 115.0^{b}$ & $7.0\times10^{-8}$ & $1.9\times10^{-16}$ & 5\\
      &  & 21.90 & $204.0\pm41.0$ & $2.5\times10^{-8}$ & $3.2\times10^{-16}$ & 5\\
      &  & 43.00 & $98.0\pm19.6^{b}$& $1.2\times10^{-8}$ & $5.9\times10^{-16}$ & 5\\
%      &  & 10.20 & 486.0$\pm$60 & 5.9$\times10^{-8}$ & 1.6$\times10^{-16}$ & \\
%      &  & 21.90 & 173.0 & 2.1$\times10^{-8}$ & 2.7$\times10^{-16}$ & \\
      &  & 22.00 & $290.0\pm45$ & $3.5\times10^{-8}$ & $4.6\times10^{-16}$ & 10*\\
      &  & 23.00 & $320.0\pm64.0^{b}$& $3.9\times10^{-8}$ & $5.5\times10^{-16}$ & 4\\
      CI($^{3}$P$_{2}$--$^{3}$P$_{1}$) & 809.902 & 8.95 & $188.5\pm37.7$ & $1.0\times10^{-7}$ & $2.2\times10^{-16}$ & 11\\
      &  & 21.9 & $58.1\pm11.6$ & $3.2\times10^{-8}$ & $4.0\times10^{-16}$ & 11*\\
      \hline
      $^{12}$CO(1--0) & 115.271 & 43.00 & $343.0\pm68.6^{b}$& $5.4\times10^{-10}$ & $2.6\times10^{-17}$ & 2\\
      &  & 23.00 & $920.0\pm82.8$ & $1.4\times10^{-9}$& $2.0\times10^{-17}$ & 6*\\
      $^{12}$CO(2--1) & 230.538 & 23.00 & $1062.0\pm116.8$ & $1.3\times10^{-8}$ & $1.9\times10^{-16}$ & 7*\\
      &  & 21.00 & $926.0\pm185.2^{b}$& $1.2\times10^{-8}$ &$1.4\times10^{-16}$ & 2\\
      $^{12}$CO(3--2) & 345.796 & 21.90 & $815.6\pm163.1$ & $3.5\times10^{-8}$ & $4.4\times10^{-16}$ & 11*\\
      &  & 23.00 & $998.0\pm139.7$ & $4.2\times10^{-8}$ & $5.9\times10^{-16}$ & 7\\
      &  & 23.00 & $1194.0\pm238.8^{b}$ & $5.0\times10^{-8}$ & $7.1\times10^{-16}$ & 2\\
      &  & 14.00 & $1200.0\pm240.0^{b}$ & $5.1\times10^{-8}$ & $2.6\times10^{-16}$ & 5\\
      &  & 21.90 & $618.9\pm123.8$ & $2.6\times10^{-8}$ & $3.3\times10^{-16}$ & 5\\
      &  & 22.00 & $680.0\pm60.0$ & $2.9\times10^{-8}$ & $3.7\times10^{-16}$ & 8\\
      $^{12}$CO(4--3) & 461.041 & 15.00 & $507.0\pm101.4^{b}$ & $5.1\times10^{-8}$ & $3.0\times10^{-16}$ & 3\\
      &  & 21.90 & $285.3\pm57.1$ & $2.9\times10^{-8}$ & $3.7\times10^{-16}$ & 3\\
      &  & 22.00 & $1019.0\pm120$ & $1.0\times10^{-7}$ & $1.3\times10^{-15}$ & 9*\\
      &  & 10.40 & $2160.0\pm432.0^{b}$ & $2.1\times10^{-7}$ & $6.2\times10^{-16}$ & 5\\
      &  & 21.90 & $786.2\pm157.2$ & $7.9\times10^{-7}$ & $1.0\times10^{-15}$ & 5\\
%     &  & 43.00 & 285$\pm$? & 2.9$\times10^{-8}$ & 1.4$\times10^{-15}$ & 3\\
      $^{12}$CO(6--5) & 691.473 & 10.60 & $1394\pm278.8$ & $4.7\times10^{-7}$ & $1.4\times10^{-15}$ & 11\\
      &  & 21.90 & $518.3\pm104.3$ & $1.8\times10^{-7}$ & $2.2\times10^{-15}$ & 11*\\
      &  & 8/30 & $861\pm258.3$ & $2.9\times10^{-7}$ & $5.0\times10^{-15}$ & 1\\
      $^{12}$CO(7--6) & 806.652 & 8.95 & $810.2\pm162.0$ & $4.3\times10^{-7}$ & $9.3\times10^{-16}$ & 11\\
      &  & 21.90 & $249.9\pm50.3$ & $1.3\times10^{-7}$ & $1.7\times10^{-15}$ & 11*\\
      &  & 11.5/60 & $1370\pm411$ & $7.3\times10^{-7}$ & $2.6\times10^{-15}$ & 10\\
      \hline
      $^{13}$CO(1--0) & 110.201 & 23.00 & $80\pm8.0$ & $1.1\times10^{-10}$ & $1.5\times10^{-18}$ & 7*\\
      $^{13}$CO(2--1) & 220.399 & 23.00 & $82\pm9.8$ & $9.0\times10^{-10}$ & $1.3\times10^{-17}$ & 7*\\
      &  & 21.00 & $104\pm20.8^{b}$& $1.1\times10^{-9}$ & $1.3\times10^{-17}$ & 2\\
      $^{13}$CO(3--2) & 330.588 & 23.00 & $90\pm12.6$ & $3.3\times10^{-9}$ & $4.7\times10^{-17}$ & 7*\\
      &  & 23.00 & $210\pm42.0^{b}$ & $7.8\times10^{-9}$ &$1.1\times10^{-16}$ & 2\\
      \hline
    \end{tabular}
  %\end{center}
\par
$^{a}$~References: 1:~Harris et~al.~(\cite{Harris91}); 2:~Wall et~al.~(\cite{Wall91}); 3:~Guesten et~al.~(\cite{Guesten93}); 4:~Harrison et~al.~(\cite{Harrison95}); 5:~Israel et~al.~(\cite{Israel95}); 6:~Mauersberger et~al.~(\cite{Mauersberger96}); 7:~Harrison et~al.~(\cite{Harrison99}); 8:~Dumke et~al.~(2001); 9:~Israel \& Baas~(\cite{Israel02}); 10:~Bradford et~al.~(\cite{Bradford03}); 11:~this work; *:~used for models.\\$^{b}$ The error is not given in the referenced paper. It has been estimated to be 20\%.
\end{table}