\begin{table}%t1 \caption{\label{table:fit}Parameters of linear fits of FIR surface brightness versus the HI~line area.} \small%\centerline { \begin{tabular}{lccc} \hline \hline Field & $\lambda$ & Offset & Slope \\ & ($\mu$m) & (MJy~sr$^{-1}$) & ($10^{-3}$ MJy~sr$^{-1}$~K$^{-1}$~km$^{-1}$~s) \\ \hline EBL22 & 90 & 5.53 (0.30) & 35.15 (4.26) \\ EBL22 & 150 & 3.56 (0.34) & 38.91 (4.38) \\ EBL22 & 180 & 3.10 (0.38) & 27.95 (5.42) \\ EBL26$^1$ & 90 & 18.66 (1.22) & 17.28 (6.57) \\ EBL26$^1$ & 150 & 6.38 (1.33) & 27.42 (7.36) \\ EBL26$^1$ & 180 & 6.00 (1.30) & 25.76 (7.41) \\ NGP & 90 & 6.31 (0.17) & 24.60 (3.98) \\ NGP & 150 & 3.53 (0.23) & 28.61 (5.58) \\ NGP & 180 & 3.20 (0.19) & 31.91 (4.22) \\ \hline \end{tabular}} \medskip The 1-$\sigma$ error estimates determined with the bootstrap method are given in parentheses. For NGP, the results correspond to a fit to the combined data of the northern and southern sub-fields (see Appendix~\ref{sect:isophot_reduction}). \\ $^1$ Fit to data with $W({\rm HI})<$ 200~K~km~s$^{-1}$ only. \end{table}