On the connection between the metal-enriched intergalactic medium and galaxies: An OVI-galaxy cross-correlation study at z 1

We present new results on the auto- and cross-correlation functions of galaxies and OVI absorbers in a ~18 Gpc3 comoving volume at z < 1. We use a sample of 51 296 galaxies and 140 OVI absorbers in the column density range 13 ≲ log N ≲ 15 to measure twopoint correlation functions in the two dimensions transverse and orthogonal to the line of sight ξ (r⊥, r||). We furthermore infer the corresponding 'real-space' correlation functions, ξ (r), by projecting ξ (r⊥, r||) along r||, and assuming a power-law form, ξ (r) = (r/r0)-γ. Comparing the results from the absorber-galaxy cross-correlation function, ξ ag, the galaxy autocorrelation function, ξ gg, and the absorber autocorrelation function, ξ aa, we constrain the statistical connection between galaxies and the metal-enriched intergalactic medium as a function of star formation activity. We also compare these results to predictions from the EAGLE cosmological hydrodynamical simulation and find a reasonable agreement. We find that: (i) OVI absorbers show very little velocity dispersion with respect to galaxies on ~ Mpc scales, likely ≲100 km s-1; (ii)OVI absorbers are less clustered, and potentially more extended around galaxies than galaxies are around themselves; (iii) on ≳ 100 kpc scales, the likelihood of finding OVI absorbers around star-forming galaxies is similar to the likelihood of finding OVI absorbers around non-star-forming galaxies; and (iv) OVI absorbers are either not ubiquitous to galaxies in our sample, or their distribution around them is patchy on scales ≳ 100 kpc (or both), at least for the column densities at which most are currently detected.