Far-infrared line and dust emission from H II regions and photodissociation regions

We explore the effect of varying the spectral energy distribution of the incident continuum, by simultaneously and self-consistently computing the structure of an H II region and a photodissociation region that are in pressure equilibrium. The results of the calculations are applied to extragalactic observations. The intensity ratio diagrams of far-infrared (FIR) emission for Herschel bands (70, 110, 160, 250, 350, and 500 {\mu}m) and the contribution from H II regions for these specific FIR emissions are presented for the first time. With these diagrams, we compare the predicted FIR continuum intensity ratios of M82 with observations by Herschel.