On the connection between the metal-enriched intergalactic medium and galaxies: an O VI–galaxy cross-correlation study at z < 1

Finn, C.W.; Morris, S.L.; Tejos, N.; Crighton, N.H.M.; Perry, R.; Fumagalli, M.; Bielby, R.; Theuns, T.; Schaye, J.; Shanks, T.; Liske, J.; Gunawardhana, M.L.P.; Bartle, S.

Abstract

We present new results on the auto- and cross-correlation functions of galaxies and O VI absorbers in a ∼18 Gpc3 comoving volume at z < 1. We use a sample of 51 296 galaxies and 140 O VI absorbers in the column density range 13 ≲ log N ≲ 15 to measure two-point 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, ξag, the galaxy autocorrelation function, ξgg, and the absorber autocorrelation function, ξaa, 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) O VI absorbers show very little velocity dispersion with respect to galaxies on ∼ Mpc scales, likely ≲100 km s−1; (ii) O VI absorbers are less clustered, and potentially more extended around galaxies than galaxies are around themselves; (iii) on ≳100 kpc scales, the likelihood of finding O VI absorbers around star-forming galaxies is similar to the likelihood of finding O VI absorbers around non-star-forming galaxies; and (iv) O VI 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.

Citation

Finn, C., Morris, S., Tejos, N., Crighton, N., Perry, R., Fumagalli, M., …Bartle, S. (2016). On the connection between the metal-enriched intergalactic medium and galaxies: an O VI–galaxy cross-correlation study at z < 1. Monthly Notices of the Royal Astronomical Society, 460(1), 590-616. https://doi.org/10.1093/mnras/stw918

• Journal Article Type: Article
• Acceptance Date: Apr 18, 2016
• Online Publication Date: Apr 21, 2016
• Publication Date: Jul 21, 2016
• Deposit Date: May 24, 2016
• Publicly Available Date: May 31, 2016
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 460
• Issue: 1
• Pages: 590-616
• DOI: https://doi.org/10.1093/mnras/stw918