RGS-1 spectrum of 4C +74.26 in the 23.0–25.5 wavelength region. The vertical dash-dotted lines mark the positions of the resonance, intercombination, and forbidden lines. The solid line represents the fit with a narrow profiled O vii triplet, which we were forced to reject (see Sect. 4.5). The dotted line represents our best fit model with a single Gaussian line representing a broadened O vii triplet. In both cases, the triplet profile is affected by absorption from ionized oxygen (O vii) intrinsic to the source as labeled. The spectrum has been rebinned for clarity.