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

Vivienne Wild, Guinevere Kauffmann, Simon White, Donald York, Matthew Lehnert, Timothy Heckman, Patrick B. Hall, Pushpa Khare, Britt Lundgren, Donald P. Schneider, Daniel Vanden Berk

Research output: Contribution to journalReview articlepeer-review

88 Citations (Scopus)


Using data from the Sloan Digital Sky Survey data release 3 (SDSS DR3), we investigate how narrow (< 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 < z < 4 and the Mg II absorbers in the range 0.4 < z < 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) similar to 5h(-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 similar to 300 kpc (C IV) and similar to 800 kpc (Mg II) along their lines of sight; (ii) that greater than or similar to 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.

Original languageEnglish
Pages (from-to)227-241
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Publication statusPublished - 21 Jul 2008


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