NIHAO IX: The role of gas inflows and outflows in driving the contraction and expansion of cold dark matter haloes

Aaron A. Dutton, Andrea Maccio, Avishai Dekel, Liang Wang, Gregory Stinson, Aura Obreja, Arianna Di Cintio, Chris Brook, Tobias Buck, Xi Kang

Research output: Contribution to journalArticle

Abstract

We use ∼100 cosmological galaxy formation 'zoom-in' simulations using the smoothed particle hydrodynamics code GASOLINE to study the effect of baryonic processes on the mass profiles of cold dark matter haloes. The haloes in our study range from dwarf (M200 ∼ 1012M⊙) to Milky Way (M200 ∼ 1012M⊙) masses. Our simulations exhibit a wide range of halo responses, primarily varying with mass, from expansion to contraction, with up to factor ∼10 changes in the enclosed dark matter mass at 1 per cent of the virial radius. Confirming previous studies, the halo response is correlated with the integrated efficiency of star formation: εSF = (MMstar/M200)/(ωbm). In addition, we report a new correlation with the compactness of the stellar system: εR = r1/2/R200. We provide an analytic formula depending on εSF and εR for the response of cold dark matter haloes to baryonic processes. An observationally testable prediction is that, at fixed mass, larger galaxies experience more halo expansion, while the smaller galaxies more halo contraction. This diversity of dark halo response is captured by a toy model consisting of cycles of adiabatic inflow (causing contraction) and impulsive gas outflow (causing expansion). For net outflow, or equal inflow and outflow fractions, f, the overall effect is expansion, with more expansion with larger f. For net inflow, contraction occurs for small f (large radii), while expansion occurs for large f (small radii), recovering the phenomenology seen in our simulations. These regularities in the galaxy formation process provide a step towards a fully predictive model for the structure of cold dark matter haloes.

Original languageEnglish (US)
JournalMonthly Notices of the Royal Astronomical Society
Volume461
Issue number3
DOIs
StatePublished - Sep 21 2016

Fingerprint

contraction
halos
dark matter
inflow
outflow
expansion
gases
gas
simulation
galactic evolution
radii
galaxies
hydrodynamics
cold
stellar systems
void ratio
phenomenology
regularity
prediction
star formation

Keywords

  • Cosmology: theory
  • Dark matter
  • Galaxies: formation
  • Galaxies: haloes
  • Galaxies: structure
  • Methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

NIHAO IX : The role of gas inflows and outflows in driving the contraction and expansion of cold dark matter haloes. / Dutton, Aaron A.; Maccio, Andrea; Dekel, Avishai; Wang, Liang; Stinson, Gregory; Obreja, Aura; Cintio, Arianna Di; Brook, Chris; Buck, Tobias; Kang, Xi.

In: Monthly Notices of the Royal Astronomical Society, Vol. 461, No. 3, 21.09.2016.

Research output: Contribution to journalArticle

Dutton, Aaron A. ; Maccio, Andrea ; Dekel, Avishai ; Wang, Liang ; Stinson, Gregory ; Obreja, Aura ; Cintio, Arianna Di ; Brook, Chris ; Buck, Tobias ; Kang, Xi. / NIHAO IX : The role of gas inflows and outflows in driving the contraction and expansion of cold dark matter haloes. In: Monthly Notices of the Royal Astronomical Society. 2016 ; Vol. 461, No. 3.
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abstract = "We use ∼100 cosmological galaxy formation 'zoom-in' simulations using the smoothed particle hydrodynamics code GASOLINE to study the effect of baryonic processes on the mass profiles of cold dark matter haloes. The haloes in our study range from dwarf (M200 ∼ 1012M⊙) to Milky Way (M200 ∼ 1012M⊙) masses. Our simulations exhibit a wide range of halo responses, primarily varying with mass, from expansion to contraction, with up to factor ∼10 changes in the enclosed dark matter mass at 1 per cent of the virial radius. Confirming previous studies, the halo response is correlated with the integrated efficiency of star formation: εSF = (MMstar/M200)/(ωb/ωm). In addition, we report a new correlation with the compactness of the stellar system: εR = r1/2/R200. We provide an analytic formula depending on εSF and εR for the response of cold dark matter haloes to baryonic processes. An observationally testable prediction is that, at fixed mass, larger galaxies experience more halo expansion, while the smaller galaxies more halo contraction. This diversity of dark halo response is captured by a toy model consisting of cycles of adiabatic inflow (causing contraction) and impulsive gas outflow (causing expansion). For net outflow, or equal inflow and outflow fractions, f, the overall effect is expansion, with more expansion with larger f. For net inflow, contraction occurs for small f (large radii), while expansion occurs for large f (small radii), recovering the phenomenology seen in our simulations. These regularities in the galaxy formation process provide a step towards a fully predictive model for the structure of cold dark matter haloes.",
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T2 - The role of gas inflows and outflows in driving the contraction and expansion of cold dark matter haloes

AU - Dutton, Aaron A.

AU - Maccio, Andrea

AU - Dekel, Avishai

AU - Wang, Liang

AU - Stinson, Gregory

AU - Obreja, Aura

AU - Cintio, Arianna Di

AU - Brook, Chris

AU - Buck, Tobias

AU - Kang, Xi

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AB - We use ∼100 cosmological galaxy formation 'zoom-in' simulations using the smoothed particle hydrodynamics code GASOLINE to study the effect of baryonic processes on the mass profiles of cold dark matter haloes. The haloes in our study range from dwarf (M200 ∼ 1012M⊙) to Milky Way (M200 ∼ 1012M⊙) masses. Our simulations exhibit a wide range of halo responses, primarily varying with mass, from expansion to contraction, with up to factor ∼10 changes in the enclosed dark matter mass at 1 per cent of the virial radius. Confirming previous studies, the halo response is correlated with the integrated efficiency of star formation: εSF = (MMstar/M200)/(ωb/ωm). In addition, we report a new correlation with the compactness of the stellar system: εR = r1/2/R200. We provide an analytic formula depending on εSF and εR for the response of cold dark matter haloes to baryonic processes. An observationally testable prediction is that, at fixed mass, larger galaxies experience more halo expansion, while the smaller galaxies more halo contraction. This diversity of dark halo response is captured by a toy model consisting of cycles of adiabatic inflow (causing contraction) and impulsive gas outflow (causing expansion). For net outflow, or equal inflow and outflow fractions, f, the overall effect is expansion, with more expansion with larger f. For net inflow, contraction occurs for small f (large radii), while expansion occurs for large f (small radii), recovering the phenomenology seen in our simulations. These regularities in the galaxy formation process provide a step towards a fully predictive model for the structure of cold dark matter haloes.

KW - Cosmology: theory

KW - Dark matter

KW - Galaxies: formation

KW - Galaxies: haloes

KW - Galaxies: structure

KW - Methods: numerical

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