\begin{table}%t4
%\centering
\par
\caption{Unidentified lines in the spectrum of NGC~7027.}
\begin{tabular}{llll}
\hline\hline \noalign{\smallskip}
$\bar{\nu}_0$ (cm$^{-1}$) & $\lambda_0$ ($\mu$m) & $F$($\times$10$^{-18}$Wm$^{-2}$) & Possible carriers \\
\hline15.650 & 638.98 &  201.9 $\pm$    9.0 & NH$_2$ \\
16.983 & 588.82 &  128.1 $\pm$   20.1 & CH$_2$ \\
17.662 & 566.19 &  249.3 $\pm$   30.6 & NH$_2$ \\
17.880 & 559.28 &  101.1 $\pm$   10.8 & CH \\
17.941 & 557.38 &  120.9 $\pm$   13.2 & H37$\epsilon$ \\
18.062 & 553.65 &  121.5 $\pm$    5.1 & H$^{+}$, He$^{+}$, C$^+$, S$^+$ 28$\beta$ \\
18.939 & 528.01 &  181.8 $\pm$   11.1 & H34$\delta$; p-SH$_2$ \\
20.101 & 497.49 &  109.8 $\pm$   16.2 & H$^{+}$, He$^{+}$, C$^+$, S$^+$ 27$\beta$ \\
48.138 & 207.74 &  100.5 $\pm$    7.5 & NH$_2$, H26$\epsilon$ \\
%\input{14589_t4.tex}
\hline
\end{tabular}
\end{table}