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Using data from the Sloan Digital Sky Survey data release 3 (SDSS DR3), we investigate how narrow (&lt;700 km s −1 ) C  iv  and Mg  ii  quasar absorption‐line systems are distributed around quasars. The C  iv  absorbers lie in the redshift range 1.6 &lt;  z  &lt; 4 and the Mg  ii  absorbers in the range 0.4 &lt;  z  &lt; 2.2. By correlating absorbers with quasars on different but neighbouring lines of sight, we measure the clustering of absorbers around quasars on comoving scales between 4 and 30 Mpc. The observed comoving correlation lengths are   r  o ∼ 5 h  −1 Mpc , similar to those observed for bright galaxies at these redshifts. Comparing correlations between absorbers and the quasars, in whose spectra they are identified, then implies: (i) that quasars destroy absorbers to comoving distances of ∼300 kpc (C  iv ) and ∼800 kpc (Mg  ii ) along their lines of sight; (ii) that ≳40 per cent of C  iv  absorbers within 3000 km s −1  of the quasi‐stellar object are not a result of large‐scale clustering but rather are directly associated with the quasar itself; (iii) that this intrinsic absorber population extends to outflow velocities of the order of 12 000 km s −1 ; (iv) that this outflow component is present in both radio‐loud and radio‐quiet quasars and (v) that a small high‐velocity outflow component is also observed in the Mg  ii  population. We also find an indication that absorption systems within 3000 km s −1  are more abundant for radio‐loud quasars than for radio‐quiet quasars. This suggests either that radio‐loud objects live in more massive haloes, or that their radio activity generates an additional low‐velocity outflow, or both.

Narrow associated quasi‐stellar object absorbers: clustering, outflows and the line‐of‐sight proximity effect