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

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

Abstract

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.

Citation

Puchwein, E., Bolton, J. S., Keating, L. C., Molaro, M., Gaikwad, P., Kulkarni, G., Haehnelt, M. G., Iršič, V., Šoltinský, T., Viel, M., Aubert, D., Becker, G. D., & Meiksin, A. (2023). The Sherwood-Relics simulations: overview and impact of patchy reionization and pressure smoothing on the intergalactic medium. Monthly Notices of the Royal Astronomical Society, 519(4), 6162-6183. https://doi.org/10.1093/mnras/stac3761

• Journal Article Type: Article
• Acceptance Date: Dec 15, 2022
• Online Publication Date: Dec 23, 2022
• Publication Date: 2023-03
• Deposit Date: Dec 19, 2022
• Publicly Available Date: Jan 13, 2023
• 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: 519
• Issue: 4
• Pages: 6162-6183
• DOI: https://doi.org/10.1093/mnras/stac3761
• Keywords: Methods: numerical, intergalactic medium, dark ages, reionization, first stars
• Public URL: https://nottingham-repository.worktribe.com/output/15158772
• Publisher URL: https://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/stac3761/6958814?redirectedFrom=fulltext
• Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record 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, The Sherwood-Relics simulations: overview and impact of patchy reionization and pressure smoothing on the intergalactic medium, Monthly Notices of the Royal Astronomical Society, 2022, stac3761 is available online at: https://doi.org/10.1093/mnras/stac3761