The Three Hundred Project: Substructure in hydrodynamical and dark matter simulations of galaxy groups around clusters

Haggar, Roan; Pearce, Frazer R; Gray, Meghan E; Knebe, Alexander; Yepes, Gustavo

Abstract

Dark matter-only simulations are able to produce the cosmic structure of a Lambda cold dark matter universe, at a much lower computational cost than more physically motivated hydrodynamical simulations. However, it is not clear how well smaller substructure is reproduced by dark matter-only simulations. To investigate this, we directly compare the substructure of galaxy clusters and of surrounding galaxy groups in hydrodynamical and dark matter-only simulations. We utilize thethreeHundred project, a suite of 324 simulations of galaxy clusters that have been simulated with hydrodynamics, and in dark matter-only. We find that dark matter-only simulations underestimate the number density of galaxies in the centres of groups and clusters relative to hydrodynamical simulations, and that this effect is stronger in denser regions. We also look at the phase space of infalling galaxy groups, to show that dark matter-only simulations underpredict the number density of galaxies in the centres of these groups by about a factor of four. This implies that the structure and evolution of infalling groups may be different to that predicted by dark matter-only simulations. Finally, we discuss potential causes for this underestimation, considering both physical effects, and numerical differences in the analysis.

• Journal Article Type: Article
• Acceptance Date: Dec 22, 2020
• Online Publication Date: Jan 11, 2021
• Publication Date: 2021-03
• Deposit Date: Feb 25, 2021
• Publicly Available Date: Feb 25, 2021
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press (OUP)
• Peer Reviewed: Peer Reviewed
• Volume: 502
• Issue: 1
• Pages: 1191-1204
• DOI: https://doi.org/10.1093/mnras/stab064
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://nottingham-repository.worktribe.com/output/5350372
• Publisher URL: https://academic.oup.com/mnras/article-abstract/502/1/1191/6081039?redirectedFrom=fulltext
• Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2021 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.