Correlation of low z Lyman-α absorbers with HI-selected galaxies

In this work, observational evidence for the connection between low column density Lyman-α 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 cm^-2) Lyman-α 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.