Testing the effect of galactic feedback on the IGM at z ∼ 6 with metal-line absorbers
Keating, Laura C
Haehnelt, Martin Gerhard
Bolton, James S
- Publisher: Monthly Notices of the Royal Astronomical Society
numerical [methods] | high-redshift [galaxies] | Astrophysics - Astrophysics of Galaxies | intergalactic medium | absorption lines [quasars] | dark ages, reionization, first stars | Astrophysics - Cosmology and Nongalactic Astrophysics
We present models of low- and high-ionization metal-line absorbers (O i, C ii, C iv and Mg ii) during the end of the reionization epoch, at z ∼ 6. Using four cosmological hydrodynamical simulations with different feedback schemes (including the Illustris and Sherwood simulations) and two different choices of hydro-solver, we investigate how the overall incidence rate and equivalent width distribution of metal-line absorbers varies with the galactic wind prescription. We find that the O i and C ii absorbers are reasonably insensitive to the feedback scheme. All models, however, struggle to reproduce the observations of C iv and Mg ii, which are probing down to lower overdensities than O i and C ii at z ∼ 6, suggesting that the metals in the simulations are not being transported out into the intergalactic medium efficiently enough. The situation is improved but not resolved if we choose a harder (but still reasonable) and/or (locally) increased UV background at z ∼ 6.
LCK acknowledges the support of an Isaac Newton Studentship, the Cambridge Trust and STFC. Support by the FP7 ERC Advanced Grant Emergence-320596 is gratefully acknowledged. EP acknowledges support from the Kavli Foundation. SB was supported by the National Aeronautics and Space Administration through Einstein Postdoctoral Fellowship Award Number PF5-160133 issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. JSB acknowledges the support of a Royal Society University Research Fellowship. This work used the DIRAC Shared Memory Processing system at the University of Cambridge, operated by the COSMOS Project at the Department of Applied Mathematics and Theoretical Physics on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by BIS National E-infrastructure capital grant ST/J005673/1, STFC capital grant ST/H008586/1 and STFC DiRAC Operations grant ST/K00333X/1. This work also used the DiRAC Data Analytic system at the University of Cambridge, operated by the University of Cambridge High Performance Computing Service on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by BIS National E-infrastructure capital grant (ST/K001590/1), STFC capital grants ST/H008861/1 and ST/H00887X/1, and STFC DiRAC Operations grant ST/K00333X/1. DiRAC is part of the National E-Infrastructure. We acknowledge PRACE for awarding us access to the Curie supercomputer, based in France at the Tres Grand Centre de Calcul (TGCC), through the 8th regular call.
This is the final version of the article. It first appeared from Oxford University Press via http://dx.doi.org/ 10.1093/mnras/stw1306