Various emission lines (identified by wavelength only) ratioed to H
, as a function of radiation parameter, U. Two sets of models are calculated, one for solar metallicity and one for 1/10th solar. The calculation is for a single optically thick cloud, ionized by a power law spectrum f
-1.5
Data on Seyfert and LINER galaxies plotted on ratio-ratio diagrams. The solid lines give the results of the same photoionization calculations as shown above. The aim of this paper was to suggest that the LINER galaxies were simply Seyferts but with lower radiation parameters (due to weaker central ionizing sources).
Figures from Ferland and Netzer, 1983 [o-link]