The Spread of Metals into the Low-Redshift Intergalactic Medium [GA]

We investigate the association between galaxies and metal-line and metal-free absorbers in the local universe ($z < 0.16$) using a large compilation of FUV spectra of bright AGN targets observed with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. In this homogeneous sample of 24 O VI detections ($Z \geq 0.1\,Z_{\odot}$) and 25 non-detections, the maximum distance O VI extends from galaxies of various luminosities is $\sim0.6$ Mpc, or $\sim5\,R_{vir}$, confirming and refining earlier results. This is an important value that must be matched by numerical simulations, which input the strength of galactic winds at the sub-grid level. We present evidence that the primary contributors to the spread of metals into the circum- and intergalactic media are $L<L^*$ galaxies. The maximum distances that metals are transported from these galaxies is comparable to the size of a small, spiral-rich group of galaxies. This suggests that, while rather pristine intergalactic material may accrete onto these groups where it can mix with metal-bearing clouds, the metals produced by the group galaxies may not leave the group, creating a nearly “closed box” for galactic evolution.

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C. Pratt, J. Stocke, B. Keeney, et. al.
Mon, 19 Jun 17

Comments: 11 pages, 3 figures, 2 tables