On the connection between the metal-enriched intergalactic medium and galaxies: an O VI-galaxy cross-correlation study at z < 1
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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2016
- DOI:
- 10.1093/mnras/stw918
- arXiv:
- arXiv:1604.02150
- Bibcode:
- 2016MNRAS.460..590F
- Keywords:
-
- galaxies: formation;
- intergalactic medium;
- quasars: absorption lines;
- large-scale structure of Universe;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Revised submission to MNRAS, having addressed the referee's comments. 27 pages, 19 figures, 5 tables