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NIHAO project II: halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations

Butsky, Iryna and Macciò, Andrea V. and Dutton, Aaron A. and Wang, Liang and Obreja, Aura and Stinson, Greg S. and Penzo, Camilla and Kang, Xi and Keller, Ben W. and Wadsley, James (2016) NIHAO project II: halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations. Monthly Notices of the Royal Astronomical Society, 462 (1). pp. 663-680. ISSN 0035-8711. https://resolver.caltech.edu/CaltechAUTHORS:20161014-143223114

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Abstract

We use the NIHAO (Numerical Investigation of Hundred Astrophysical Objects) cosmological simulations to study the effects of galaxy formation on key properties of dark matter (DM) haloes. NIHAO consists of ≈90 high-resolution smoothed particle hydrodynamics simulations that include (metal-line) cooling, star formation, and feedback from massive stars and supernovae, and cover a wide stellar and halo mass range: 10^6 ≲ M^*/M_⊙ ≲ 10^(11)(10^(9.5) ≲ M_(halo)/M_⊙ ≲ 10^(12.5)). When compared to DM-only simulations, the NIHAO haloes have similar shapes at the virial radius, R_(vir), but are substantially rounder inside ≈0.1Rvir. In NIHAO simulations, c/a increases with halo mass and integrated star formation efficiency, reaching ∼0.8 at the Milky Way mass (compared to 0.5 in DM-only), providing a plausible solution to the long-standing conflict between observations and DM-only simulations. The radial profile of the phase-space Q parameter (ρ/σ^3) is best fit with a single power law in DM-only simulations, but shows a flattening within ≈0.1R_(vir) for NIHAO for total masses M > 10^(11) M_⊙. Finally, the global velocity distribution of DM is similar in both DM-only and NIHAO simulations, but in the solar neighbourhood, NIHAO galaxies deviate substantially from Maxwellian. The distribution is more symmetric, roughly Gaussian, with a peak that shifts to higher velocities for Milky Way mass haloes. We provide the distribution parameters which can be used for predictions for direct DM detection experiments. Our results underline the ability of the galaxy formation processes to modify the properties of DM haloes.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1093/mnras/stw1688DOIArticle
http://mnras.oxfordjournals.org/content/462/1/663.abstractPublisherArticle
https://arxiv.org/abs/1503.04814arXivDiscussion Paper
Additional Information:© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 July 12. Received 2016 July 7. In original form 2015 March 19. First published online July 14, 2016. We thanks an anonymous referee whose comments strongly improved the presentation of our results. The simulations were performed on the theo cluster of the Max Planck Institute for Astronomy, and hydra cluster, both based at the Rechenzentrum in Garching, and on the High Performance Computing resources at New York University Abu Dhabi. AVM, AAD, and GSS acknowledge support from the Sonderforschungsbereich SFB 881 ‘The Milky Way System’ (subproject A1) of the German Research Foundation (DFG). IB contribution to this project was made possible through the SURF program at Caltech, and was supported by the Flintridge Foundation, Caltech SFP Office, and Christian Ott. IB also acknowledges support from the Sonderforschungsbereich SFB 881 ‘The Milky Way System’ (subproject A1) of the German Research Foundation (DFG) during her stay at the MPIA. XK acknowledge the support from NSFC project No.11333008. CP is supported by funding made available by ERC-StG/EDECS n. 279954. Finally, IB would like to thank Lynne Hillenbrand for her guidance in writing this paper.
Funders:
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)SFB 881
Deutsche Forschungsgemeinschaft (DFG)‘The Milky Way System’ (subproject A1)
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Flintridge FoundationUNSPECIFIED
Caltech Student-Faculty Program OfficeUNSPECIFIED
National Science Foundation of China11333008
European Research Council (ERC)279954
Subject Keywords:Galaxy: disc Galaxy: evolution Galaxy: structure galaxies: evolution galaxies: interactions galaxies: structure methods: numerical
Issue or Number:1
Record Number:CaltechAUTHORS:20161014-143223114
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20161014-143223114
Official Citation:Iryna Butsky, Andrea V. Macciò, Aaron A. Dutton, Liang Wang, Aura Obreja, Greg S. Stinson, Camilla Penzo, Xi Kang, Ben W. Keller, and James Wadsley NIHAO project II: halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations MNRAS (October 11, 2016) Vol. 462 663-680 doi:10.1093/mnras/stw1688 first published online July 14, 2016
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:71117
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:14 Oct 2016 22:13
Last Modified:03 Oct 2019 16:04

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