H₂O lines in the blue and green bands (λ < 100 μm) detected in NGC 4418 (upper spectra in each panel) and Arp 220 (lower spectra). The spectra, histograms with black solid lines, have been scaled by a factor of 0.5 in panels k) and p). Vertical dotted lines indicate the rest wavelengths of the lines relative to z = 0.00705 and 0.0181 for NGC 4418 and Arp 220, respectively. Model results are also shown. For NGC 4418, the blue and light-blue curves show the models for the C_core and C_warm components, respectively; for Arp 220, the blue and light-blue lines show the estimated contributions from C_west and C_east , and the green curve (in panel k) shows the contribution by C_extended . Red is total. Model parameters are given in Tables 1 and 2.