Origin of temperature constraints in CIE WHIM modeling. The figure illustrates CIE model temperature dependencies of various ionic line strengths relative to that of the O VIII Lyman α line. The dashed sections mark the regions where the W_ion/W_OVIII ratio is inconsistent with the 1σ limits of slab modeling. The ions shown in the figure produce the most important absorption lines in the spectra in the examined wavelength band of 14–28 Å and thus constrain the CIE temperature, marked with the shaded region. The data of the strongest available ionic lines were used to generate this figure.