Misc,
On the connection between the metal-enriched intergalactic medium and galaxies: an OVI-galaxy cross-correlation study at $z < 1$
(2016)cite arxiv:1604.02150Comment: Revised submission to MNRAS, having addressed the referee's comments. 27 pages, 19 figures, 5 tables.
Abstract
We present new results on the auto- and cross-correlation functions of
galaxies and OVI absorbers in a $18~Gpc^3$ comoving volume at $z
< 1$. We use a sample of 51,296 galaxies and 140 OVI absorbers in the column
density range $13 N 15$ to measure two-point correlation
functions in the two dimensions transverse and orthogonal to the line-of-sight
$\xi(r_\perp, r_\parallel)$. We furthermore infer the corresponding
'real-space' correlation functions, $\xi(r)$, by projecting $\xi(r_\perp,
r_\parallel)$ along $r_\parallel$, and assuming a power-law form, $\xi(r) =
(r / r_0)^-\gamma$. Comparing the results from the absorber-galaxy
cross-correlation function, $\xi_ag$, the galaxy auto-correlation
function, $\xi_gg$, and the absorber auto-correlation function,
$\xi_aa$, 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 $\sim$ Mpc scales, likely $łesssim$ 100 \kms; (ii) OVI absorbers
and galaxies may not linearly trace the same underlying distribution of matter
in general. In particular, our results demonstrate that 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 (abridged)
