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The Sherwood simulation suite: Overview and data comparisons with the Lyman α forest at redshifts 2 ≤ z ≤ 5

Published version
Peer-reviewed

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Authors

Bolton, JS 
Puchwein, E 
Haehnelt, MG 
Kim, TS 

Abstract

We introduce a new set of large scale, high resolution hydrodynamical simulations of the intergalactic medium: the Sherwood simulation suite. These are performed in volumes 10^3-160^3 h^-3 comoving Mpc^{3}, span almost four orders of magnitude in mass resolution with up to 17.2 billion particles, and employ a variety of physics variations including warm dark matter and galactic outflows. We undertake a detailed comparison of the simulations to high resolution, high signal-to-noise observations of the Lyman-alpha forest over the redshift range 2 < z < 5. The simulations are in very good agreement with the observational data, lending further support to the paradigm that the Lyman-alpha forest is a natural consequence of the web-like distribution of matter arising in LCDM cosmological models. Only a small number of minor discrepancies remain with respect to the observational data. Saturated Lyman-alpha absorption lines with column densities N_HI > 10^14.5 cm^-2 at 2 < z < 2.5 are underpredicted in the models. An uncertain correction for continuum placement bias is required to match the distribution and power spectrum of the transmitted flux, particularly at z > 4. Finally, the temperature of intergalactic gas in the simulations may be slightly too low at z=2.7 and a flatter temperature-density relation is required at z=2.4, consistent with the expected effects of non-equilibrium ionisation during He-II reionisation.

Description

Keywords

methods:numerical, intergalactic medium, quasars:absorption lines

Journal Title

Monthly Notices of the Royal Astronomical Society

Conference Name

Journal ISSN

0035-8711
1365-2966

Volume Title

Publisher

Oxford University Press (OUP)
Sponsorship
Science and Technology Facilities Council (ST/J005673/1)
Science and Technology Facilities Council (ST/K00333X/1)
Science and Technology Facilities Council (ST/M00418X/1)
Science and Technology Facilities Council (ST/M007065/1)
Science and Technology Facilities Council (ST/L000636/1)
European Research Council (638707)
Science and Technology Facilities Council (ST/N000927/1)
Science and Technology Facilities Council (ST/P000673/1)
Science and Technology Facilities Council (ST/L000725/1)
STFC (ST/M007073/1)
Science and Technology Facilities Council (ST/P002315/1)
Science and Technology Facilities Council (ST/R002452/1)
The hydrodynamical simulations used in this work were performed with supercomputer time awarded by the Partnership for Advanced Computing in Europe (PRACE) 8th Call. We acknowledge PRACE for awarding us access to the Curie supercomputer, based in France at the Tré Grand Centre de Calcul (TGCC). This work also made use of the DiRAC High Performance Computing System (HPCS) and the COSMOS shared memory service at the University of Cambridge. These are operated on behalf of the STFC DiRAC HPC facility. This equipment is funded by BIS National E-infrastructure capital grant ST/J005673/1 and STFC grants ST/H008586/1, ST/K00333X/1. JSB acknowledges the support of a Royal Society University Research Fellowship. MGH and EP acknowledge support from the FP7 ERC Grant Emergence-320596, and EP gratefully acknowledges support by the Kavli Foundation. DS acknowledges support by the STFC and the ERC starting grant 638707 ‘Black holes and their host galaxies: co-evolution across cosmic time’. JAR is supported by grant numbers ST/L00075X/1 and RF040365. MV and TSK are supported by the FP7 ERC grant ‘cosmoIGM’ and the INFN/PD51 grant.