As in the bottom panel of Fig. 4, but for n_H(i,φ = 0.961) as a function of i. Solution for X^H+ = 100 was added to demonstrate the small change of i for very high X^H+ (Sect. 4.1). Intersections of the model curves with the horizontal line at the observed value of n_H = 3.9 × 10²² cm^-2 correspond to i = 57, 59, 59.5, and 607. The shadow band represents the uncertainty in the measured n_H.