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Baryon effects on the internal structure of ΛCDM haloes in the EAGLE simulations

Schaller, Matthieu; Frenk, Carlos S.; Bower, Richard G.; Theuns, Tom; Jenkins, Adrian; Schaye, Joop; Crain, Robert A.; Furlong, Michelle; Dalla Vecchia, Claudio; McCarthy, Ian G.

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Richard G. Bower

Joop Schaye

Robert A. Crain

Michelle Furlong

Claudio Dalla Vecchia

Ian G. McCarthy


We investigate the internal structure and density profiles of haloes of mass 1010–1014 M⊙ in the Evolution and Assembly of Galaxies and their Environment (EAGLE) simulations. These follow the formation of galaxies in a Λ cold dark matter Universe and include a treatment of the baryon physics thought to be relevant. The EAGLE simulations reproduce the observed present-day galaxy stellar mass function, as well as many other properties of the galaxy population as a function of time. We find significant differences between the masses of haloes in the EAGLE simulations and in simulations that follow only the dark matter component. Nevertheless, haloes are well described by the Navarro–Frenk–White density profile at radii larger than ∼5 per cent of the virial radius but, closer to the centre, the presence of stars can produce cuspier profiles. Central enhancements in the total mass profile are most important in haloes of mass 1012–1013 M⊙, where the stellar fraction peaks. Over the radial range where they are well resolved, the resulting galaxy rotation curves are in very good agreement with observational data for galaxies with stellar mass M* < 5 × 1010 M⊙. We present an empirical fitting function that describes the total mass profiles and show that its parameters are strongly correlated with halo mass.


Schaller, M., Frenk, C. S., Bower, R. G., Theuns, T., Jenkins, A., Schaye, J., …McCarthy, I. G. (2015). Baryon effects on the internal structure of ΛCDM haloes in the EAGLE simulations. Monthly Notices of the Royal Astronomical Society, 451(2), 1247-1267.

Journal Article Type Article
Acceptance Date May 11, 2015
Online Publication Date Jun 4, 2015
Publication Date Aug 1, 2015
Deposit Date Oct 22, 2015
Publicly Available Date Nov 5, 2015
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 451
Issue 2
Pages 1247-1267
Keywords Cosmology: theory, Dark matter, Large-scale structure of Universe.
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Published Journal Article (8.2 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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