The Absorption Spectrum of the QSO PKS 2126-158 (z_em = 3.27) and the Clustering Properties of Metal Systems

We report the detection of a significant clustering signal on scales $\Delta v < 300$ km/s, for a sample of 71 C IV absorbers. This result confirms previous findings and, together with data at lower column density, it points to a trend of decreasing clustering amplitude with decreasing column density, analogous to that observed for Lyman alpha lines.