Column density vs. ionization parameter plot for WA (red stars), E-UFO (green triangles), and UFO (blue squares). Arrows represent lower limits on the column density, with the black dots and dashed line representing the linear fit from Tombesi et al. (2013). Magenta points are soft X-ray UFOs from the literature. This plot does not show any difference from Tombesi et al. (2013), since the E-UFO only differs from the WA in its velocity.