Left: confidence contour levels of the column density N_H and the ionization parameter log(ξ/erg cm s⁻¹), for the best-fit model with two XSTAR tables, one with v_turb = 1000 km s⁻¹ for the low-ionization table UFO_L and one with v_turb = 3000 km s⁻¹ for the high-ionization UFO_H one. Right: contour plot of the outflow velocity for the UFO_H in red and for UFO_L in green. The blue lines mark one parameter’s 90, 99, and 99.9% confidence levels.