Theoretical “excitation temperatures” from column densities for Fe ii levels of the Cloudy models. The quantity g is the statistical weight, 2J + 1, of the levels. The larger symbols are for levels that correspond to the lines used in Fig. 12. The heavy line is a least squares solution giving T = 11 134 K. Smaller symbols are for all 256 levels used in the model; the lighter line corresponds to T = 7026 K.