The Hydrangea simulations: galaxy formation in and around massive clusters

Bahé, Y.M.; Barnes, D.J.; Dalla Vecchia, C.; Kay, S.T.; White, S.D.M.; McCarthy, I.G.; Schaye, J.; Bower, R.G.; Crain, R.A.; Theuns, T.; Jenkins, A.; McGee, S.L.; Schaller, M.; Thomas, P.A.; Trayford, J.W.

doi:10.1093/mnras/stx1403

The Hydrangea simulations: galaxy formation in and around massive clusters

Bahé, Y.M.; Barnes, D.J.; Dalla Vecchia, C.; Kay, S.T.; White, S.D.M.; McCarthy, I.G.; Schaye, J.; Bower, R.G.; Crain, R.A.; Theuns, T.; Jenkins, A.; McGee, S.L.; Schaller, M.; Thomas, P.A.; Trayford, J.W.

Authors

Y.M. Bahé

D.J. Barnes

C. Dalla Vecchia

S.T. Kay

S.D.M. White

I.G. McCarthy

J. Schaye

R.G. Bower

R.A. Crain

Professor Tom Theuns tom.theuns@durham.ac.uk
Professor

Professor Adrian Jenkins a.r.jenkins@durham.ac.uk
Professor

S.L. McGee

M. Schaller

P.A. Thomas

J.W. Trayford

Abstract

We introduce the Hydrangea simulations, a suite of 24 cosmological hydrodynamic zoom-in simulations of massive galaxy clusters (M200c = 1014–1015.4 M⊙) with baryon particle masses of ∼106 M⊙. Designed to study the impact of the cluster environment on galaxy formation, they are a key part of the ‘Cluster–EAGLE’ project. They use a galaxy formation model developed for the EAGLE project, which has been shown to yield both realistic field galaxies and hot gas fractions of galaxy groups consistent with observations. The total stellar mass content of the simulated clusters agrees with observations, but central cluster galaxies are too massive, by up to 0.6 dex. Passive satellite fractions are higher than in the field, and at stellar masses Mstar > 1010 M⊙, this environmental effect is quantitatively consistent with observations. The predicted satellite stellar mass function matches data from local cluster surveys. Normalized to total mass, there are fewer low-mass (Mstar ≲ 1010 M⊙) galaxies within the virial radius of clusters than in the field, primarily due to star formation quenching. Conversely, the simulations predict an overabundance of massive galaxies in clusters compared to the field that persists to their far outskirts (>5 r200c). This is caused by a significantly increased stellar mass fraction of (sub-)haloes in the cluster environment, by up to ∼0.3 dex even well beyond r200c. Haloes near clusters are also more concentrated than equally massive field haloes, but these two effects are largely uncorrelated.

Citation

Bahé, Y., Barnes, D., Dalla Vecchia, C., Kay, S., White, S., McCarthy, I., …Trayford, J. (2017). The Hydrangea simulations: galaxy formation in and around massive clusters. Monthly Notices of the Royal Astronomical Society, 470(4), 4186-4208. https://doi.org/10.1093/mnras/stx1403

Journal Article Type	Article
Acceptance Date	Jun 5, 2017
Online Publication Date	Jun 14, 2017
Publication Date	Oct 1, 2017
Deposit Date	Aug 29, 2017
Publicly Available Date	Aug 31, 2017
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Royal Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	470
Issue	4
Pages	4186-4208
DOI	https://doi.org/10.1093/mnras/stx1403

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Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2017. The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.