Posterior distribution for the simultaneous FUV and X-ray spectrum in the oxygen region. The distribution compares each pair of free parameters of the fit with two-dimensional histograms. The parameters in the plot correspond to the following quantities: N _H is the neutral hydrogen column density in units of 10²¹ cm⁻² along the line of sight; z _v is the velocity shift in km s⁻¹; ﹩\mathrm{log}({\mathrm{norm}}_{\mathrm{bb}})﹩ is the logarithm of the blackbody normalization; N _dust is the total column density of dust in 10¹⁸ cm⁻²; b refers to the line velocity broadening in km s⁻¹; O II, O III, and O IV correspond to the logarithmic ionic column densities in cm⁻²; and O_abund is the O abundance scale factor relative to Lodders & Palme (2009).