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The Sherwood simulation suite: overview and data comparisons with the Lyman-? forest at redshifts 2?z?5

Bolton, James S.; Puchwein, Ewald; Sijacki, Debora; Haehnelt, Martin G.; Kim, Tae-Sun; Meiksin, Avery; Regan, John A.; Viel, Matteo


Ewald Puchwein

Debora Sijacki

Martin G. Haehnelt

Tae-Sun Kim

Avery Meiksin

John A. Regan

Matteo Viel


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 of 103–1603h−3 comoving Mpc3, 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 Ly α 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 Ly α forest is a natural consequence of the web-like distribution of matter arising in Λcold dark matter cosmological models. Only a small number of minor discrepancies remain with respect to the observational data. Saturated Ly α absorption lines with column densities NHI>1014.5cm−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 ionization during He ii reionization.


Bolton, J. S., Puchwein, E., Sijacki, D., Haehnelt, M. G., Kim, T., Meiksin, A., …Viel, M. (2017). The Sherwood simulation suite: overview and data comparisons with the Lyman-α forest at redshifts 2≤z≤5. Monthly Notices of the Royal Astronomical Society, 464(1),

Journal Article Type Article
Acceptance Date Sep 19, 2016
Online Publication Date Sep 21, 2016
Publication Date Jan 1, 2017
Deposit Date Sep 22, 2016
Publicly Available Date Sep 22, 2016
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 464
Issue 1
Keywords methods: numerical, intergalactic medium, quasars: absorption lines
Public URL
Publisher URL
Additional Information This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 Royal Astronomical Society Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.


MNRAS-2017-Bolton-897-914.pdf (7 Mb)

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