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The separate and combined effects of baryon physics and neutrino free-streaming on large-scale structure

Mummery, BO and McCarthy, IG and Bird, S and Schaye, J (2017) The separate and combined effects of baryon physics and neutrino free-streaming on large-scale structure. Monthly Notices of the Royal Astronomical Society. ISSN 0035-8711

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Abstract

We use the cosmo-OWLS and BAHAMAS suites of cosmological hydrodynamical simulations to explore the separate and combined effects of baryon physics (particularly feedback from active galactic nuclei, AGN) and free-streaming of massive neutrinos on large-scale structure. We focus on five diagnostics: i) the halo mass function; ii) halo mass density profiles; iii) the halo mass-concentration relation; iv) the clustering of haloes; and v) the clustering of matter; and we explore the extent to which the effects of baryon physics and neutrino free-streaming can be treated independently. Consistent with previous studies, we find that both AGN feedback and neutrino free-streaming suppress the total matter power spectrum, although their scale and redshift dependencies differ significantly. The inclusion of AGN feedback can significantly reduce the masses of groups and clusters, and increase their scale radii. These effects lead to a decrease in the amplitude of the mass-concentration relation and an increase in the halo autocorrelation function at fixed mass. Neutrinos also lower the masses of groups and clusters while having no significant effect on the shape of their density profiles (thus also affecting the mass-concentration relation and halo clustering in a qualitatively similar way to feedback). We show that, with only a small number of exceptions, the combined effects of baryon physics and neutrino free-streaming on all five diagnostics can be estimated to typically better than a few percent accuracy by treating these processes independently (i.e., by multiplying their separate effects).

Item Type: Article
Additional Information: 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. All rights reserved.
Uncontrolled Keywords: astro-ph.CO; astro-ph.CO
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 26 Jun 2017 10:58
Last Modified: 26 Jun 2017 10:58
DOI or Identification number: 10.1093/mnras/stx1469
URI: http://researchonline.ljmu.ac.uk/id/eprint/6748

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