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The origin of scatter in the stellar mass-halo mass relation of central galaxies in the EAGLE simulation

Matthee, J.; Schaye, J.; Crain, R.A.; Schaller, M.; Bower, R.; Theuns, T.

The origin of scatter in the stellar mass-halo mass relation of central galaxies in the EAGLE simulation Thumbnail


Authors

J. Matthee

J. Schaye

R.A. Crain

M. Schaller

R. Bower



Abstract

We use the hydrodynamical EAGLE simulation to study the magnitude and origin of the scatter in the stellar mass–halo mass relation for central galaxies. We separate cause and effect by correlating stellar masses in the baryonic simulation with halo properties in a matched dark matter only (DMO) simulation. The scatter in stellar mass increases with redshift and decreases with halo mass. Atz = 0.1, it declines from 0.25 dex at M200,DMO ≈ 1011 M to 0.12 dex at M200,DMO ≈ 1013 M, but the trend is weak above 1012 M. For M200,DMO < 1012.5 M up to 0.04 dex of the scatter is due to scatter in the halo concentration. At fixed halo mass, a larger stellar mass corresponds to a more concentrated halo. This is likely because higher concentrations imply earlier formation times and hence more time for accretion and star formation, and/or because feedback is less efficient in haloes with higher binding energies. The maximum circular velocity, Vmax, DMO, and binding energy are therefore more fundamental properties than halo mass, meaning that they are more accurate predictors of stellar mass, and we provide fitting formulae for their relations with stellar mass. However, concentration alone cannot explain the total scatter in the Mstar–M200,DMO relation, and it does not explain the scatter in Mstar–Vmax, DMO. Halo spin, sphericity, triaxiality, substructure and environment are also not responsible for the remaining scatter, which thus could be due to more complex halo properties or non-linear/stochastic baryonic effects.

Citation

Matthee, J., Schaye, J., Crain, R., Schaller, M., Bower, R., & Theuns, T. (2017). The origin of scatter in the stellar mass-halo mass relation of central galaxies in the EAGLE simulation. Monthly Notices of the Royal Astronomical Society, 465(2), 2381-2396. https://doi.org/10.1093/mnras/stw2884

Journal Article Type Article
Acceptance Date Nov 4, 2016
Online Publication Date Nov 8, 2016
Publication Date Feb 21, 2017
Deposit Date Feb 27, 2017
Publicly Available Date Mar 28, 2024
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 465
Issue 2
Pages 2381-2396
DOI https://doi.org/10.1093/mnras/stw2884

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Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.





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