In this work, observational evidence for the connection between low column density Lyman-alpha absorbers and large-scale structure traced by gas-rich galaxies is investigated. The H I Parkes All Sky Survey (HIPASS) galaxy catalogue is cross-correlated with known low redshift, low column density (N HI<1015 cm-2) Lyman-alpha absorbers from the literature. The absorber-galaxy cross-correlation function shows that on scales from 1 -10 h-1 Mpc, absorbers are embedded in halos with masses similar to that of galaxy groups.
Proceedings of the International Astronomical Union Colloquium C199: Probing Galaxies through Quasar Absorption Lines, Shanghai, China, 14-18 March 2005 / Peter R. Williams, Cheng-Gang Shu and Brice Menard (eds.),
Vol. 1, pp. 472-474