The Sherwood-Relics simulations: overview and impact of patchy reionization and pressure smoothing on the intergalactic medium

Ewald Puchwein*, James S. Bolton, Laura C. Keating, Margherita Molaro, Prakash Gaikwad, Girish Kulkarni, Martin G. Haehnelt, Vid Iršič, Tomáš Šoltinský, Matteo Viel, Dominique Aubert, George D. Becker, Avery Meiksin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We present the Sherwood-Relics simulations, a new suite of large cosmological hydrodynamical simulations aimed at modelling the intergalactic medium (IGM) during and after the cosmic reionization of hydrogen. The suite consists of over 200 simulations that cover a wide range of astrophysical and cosmological parameters. It also includes simulations that use a new lightweight hybrid scheme for treating radiative transfer effects. This scheme follows the spatial variations in the ionizing radiation field, as well as the associated fluctuations in IGM temperature and pressure smoothing. It is computationally much cheaper than full radiation hydrodynamics simulations, and circumvents the difficult task of calibrating a galaxy formation model to observational constraints on cosmic reionization. Using this hybrid technique, we study the spatial fluctuations in IGM properties that are seeded by patchy cosmic reionization. We investigate the relevant physical processes and assess their impact on the z > 4 Lyman-α forest. Our main findings are: (i) consistent with previous studies patchy reionization causes large-scale temperature fluctuations that persist well after the end of reionization, (ii) these increase the Lyman-α forest flux power spectrum on large scales, and (iii) result in a spatially varying pressure smoothing that correlates well with the local reionization redshift. (iv) Structures evaporated or puffed up by photoheating cause notable features in the Lyman-α forest, such as flat-bottom or double-dip absorption profiles.

Original languageEnglish
Pages (from-to)6162-6183
Number of pages22
JournalMonthly Notices of the Royal Astronomical Society
Volume519
Issue number4
Early online date19 Dec 2022
DOIs
Publication statusPublished - 1 Mar 2023

Keywords / Materials (for Non-textual outputs)

  • dark ages, reionization, first stars
  • intergalactic medium
  • methods: numerical

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