The Three Hundred Project: The evolution of galaxy cluster density profiles

Robert Mostoghiu*, Alexander Knebe, Weiguang Cui, Frazer R. Pearce, Gustavo Yepes, Chris Power, Romeel Dave, Alexander Arth

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Recent numerical studies of the dark matter density profiles of massive galaxy clusters (M halo > 10 15 M) show that their median radial mass density profile remains unchanged up to z > 1, displaying a highly self-similar evolution. We verify this by using the data set of the THE THREE HUNDRED project, i.e. 324 cluster-sized haloes as found in full physics hydrodynamical simulations. We track the progenitors of the mass-complete sample of clusters at z = 0, and find that their median shape is already in place by z = 2.5. However, selecting a dynamically relaxed subsample (∼16 per cent of the clusters), we observe a shift of the scale radius r s towards larger values at earlier times. Classifying the whole sample by formation time, this evolution is understood as a result of a two-phase halo mass accretion process. Early-forming clusters – identified as relaxed today – have already entered their slow accretion phase, hence their mass growth occurs mostly at the outskirts. Late-forming clusters – which are still unrelaxed today – are in their fast accretion phase, thus the central region of the clusters is still growing. We conclude that the density profile of galaxy clusters shows a profound self-similarity out to redshifts z ∼ 2.5. This result holds for both gas and total density profiles when including baryonic physics, as reported here for two rather distinct sub-grid models.

Original languageEnglish
Pages (from-to)3390-3403
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume483
Issue number3
Early online date6 Dec 2018
DOIs
Publication statusPublished - 1 Mar 2019

Keywords / Materials (for Non-textual outputs)

  • cosmology theory
  • Dark matter

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