The Three Hundred Project: Backsplash galaxies in simulations of clusters

Haggar, Roan; Gray, Meghan E; Pearce, Frazer R; Knebe, Alexander; Cui, Weiguang; Mostoghiu, Robert; Yepes, Gustavo

Abstract

In the outer regions of a galaxy cluster, galaxies may be either falling into the cluster for the first time, or have already passed through the cluster centre at some point in their past. To investigate these two distinct populations, we utilise TheThreeHundred project, a suite of 324 hydrodynamical resimulations of galaxy clusters. In particular, we study the 'backsplash population' of galaxies; those that have passed within R 200 of the cluster centre at some time in their history, but are now outside of this radius. We find that, on average, over half of all galaxies between R 200 and 2R 200 from their host at z = 0 are backsplash galaxies, but that this fraction is dependent on the dynamical state of a cluster, as dynamically relaxed clusters have a greater backsplash fraction. We also find that this population is mostly developed at recent times (z 0.4), and is dependent on the recent history of a cluster. Finally, we show that the dynamical state of a given cluster, and thus the fraction of backsplash galaxies in its outskirts, can be predicted based on observational properties of the cluster.

Citation

Haggar, R., Gray, M. E., Pearce, F. R., Knebe, A., Cui, W., Mostoghiu, R., & Yepes, G. (2020). The Three Hundred Project: Backsplash galaxies in simulations of clusters. Monthly Notices of the Royal Astronomical Society, 492(4), 6074–6085. https://doi.org/10.1093/mnras/staa273

• Journal Article Type: Article
• Acceptance Date: Jan 24, 2020
• Online Publication Date: Feb 3, 2020
• Publication Date: Mar 1, 2020
• Deposit Date: Feb 4, 2020
• Publicly Available Date: Mar 3, 2020
• 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: 492
• Issue: 4
• Pages: 6074–6085
• DOI: https://doi.org/10.1093/mnras/staa273
• Keywords: methods: numerical, galaxies: clusters: general, galaxies: general
• Public URL: https://nottingham-repository.worktribe.com/output/3891183
• Publisher URL: https://academic.oup.com/mnras/article/492/4/6074/5721514
• Additional Information: This article has been accepted for publication in MNRAS ©: 2020 The authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.