Scatterplots

The scatterplots show the location, in parameter space, of group four, the group completely devoid of NALQSOs (green points). No single bivariate plots clearly show the separation of group four from the other groups. However, the plots show that the most important characteristics of this group appear to be:

• narrow CIV FWHM: log(CIV FWHM)<3.5
• flat Optical/X-ray spectral index: alpha_ox>-1.6
• flat radio spectral index: alpha_rad>-0.5
• radio-loud: log R^*>3.0

These are the properties that appear to inhibit the production of narrow absorption line gas.