Correlation between Civ FWHM and Civ. Pop. A sources are indicated by filled circles and Pop. B sources by filled squares. HE sources are colored blue (Pop. A) and red (Pop. B), and LOWZ sources in pale blue (Pop. A) and gold (Pop. B). The LSQ best fit line (black) refers to Pop. A sources. The dot-dashed lines at ±200 km s^-1 mark the Civ range consistent with no centroid shift. Error bars refer to 1σ level uncertainty.