\begin{table}%t1
\caption{Properties of the HNC, HCN and HCO$^+$ (5--4) lines compared to the CO(4--3) line towards APM~08279+5255}
\small
%\centerline
{\begin{tabular}{lccccc}
\hline
\hline
Line             & $\rm \nu_{\rm obs}$  & $I_{\rm line}$         & $L^\prime$                  & $F_{\rm cont}$    & Ref \\
                 &    [GHz]         & [Jy km s$^{-1}$]          &
[10$^{10}$ K km s$^{-1}$ pc$^{2}$]  &    [mJy]      &     \\
\hline
HNC(5--4)        & 92.282           & 0.54$^d\ \pm\ $0.25  & 2.3$\ \pm\ $1.1 &          1.1$^e\ \pm\ $0.15 & Present work \\
CN(4--3)         & 92.332           & 0.31$^d\ \pm\ $0.25    &1.3 $\ \pm\ $1.1             &   1.1$^e\ \pm\ $0.15        & Present work \\
\mbox{HCN(5--4)}        & 90.229           & 0.85$\ \pm\ $0.12      & 3.6$\ \pm\ $0.5                 & 1.3$\ \pm\ $0.2   &   (a)  \\
HCO$^{+}$(5--4)  & 90.797           & 0.87$\ \pm\ $0.13      & 3.5$\ \pm\ $0.6                 & 1.2$\ \pm\ $0.1   &   (b)  \\
CO(4--3)         & 93.870           & 3.70$\ \pm\ $0.50      &14.7$\ \pm\ $1.5                  & 1.2$\ \pm\ $0.3   &   (c)  \\
\hline
\end{tabular}
\label{parameters}
}\medskip
 NOTES. -- (a) We06; (b) GB06; (c) Downes et~al. (\cite{Downes1999}); (d) blended line
          HNC and
          CN fitted together with FWHP fixed
          to 400 km s$^{-1}$; (e) fitted to the line-free channels. 
          The luminosities are calculated from equation [1] of Downes et~al. (\cite{Downes1999}) using the standard
concordance cosmology parameters with $H_0 = 71$ ~ km s$^{-1}$ Mpc$^{-1}$,
$\Omega_m = 0.27$ and $\Omega_\Delta = 0.73$ (Spergel et~al. \cite{Spergel2003}). They are not corrected for the lens
amplification.
\par
\end{table}