The Galaxy Environment of O VI Absorption Systems

We combine a FUSE sample of O VI absorbers (z < 0:15) with a database of 1.07 million galaxy redshifts to explore the relationship between absorbers and galaxy environments. All 37 absorbers with NOVI 1013:2 cm−2 lie within 800 h−170 kpc of the nearest galaxy, with no compelling evidence for O VI absorbers in voids. The O VI absorbers often appear to be associated with environments of individual galaxies. Gas with 10 % solar metallicity (O VI and C III) has a median spread in distance of 350{500 h−170 kpc around L? galaxies and 200{270 h−170 kpc around 0.1L? galaxies, with ranges accounting for uncertain metallicity of gas undetected in Ly absorption. In order to match the O VI absorber line fre-quency, (dN =dz) 20, galaxies with L 0:1L? must contribute to the cross section. Lyman- absorbers with NHI 1013:2 cm−2 cover 50 % of the surface area of typical large-scale structure laments. Two-thirds of these show O VI and/or C III absorption, corresponding to a 33{50 % covering factor at 0:1Z and suggesting that metals are spread to a maximum distance of 800 h−170 kpc, within typical galaxy supercluster laments. Approximately 50 % of the O VI absorbers have associated Ly line pairs with separations (v)Ly = 50−200 k-m s−1. These pairs could represent shocks at the speeds necessary to create copious O VI. They lie within 100 h−170 kpc of the nearest galaxy and account for most of the two-point correlation function of low-z Ly forest absorbers at (v)Ly 200 km s−1