NIHAO project II

Halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations

Iryna Butsky, Andrea Maccio, Aaron A. Dutton, Liang Wang, Aura Obreja, Greg S. Stinson, Camilla Penzo, Xi Kang, Ben W. Keller, James Wadsley

    Research output: Contribution to journalArticle

    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: 106 ≲ M*/M ≲ 1011(109.5 ≲ Mhalo/M ≲ 1012.5). When compared to DM-only simulations, the NIHAO haloes have similar shapes at the virial radius, Rvir, 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/σ3) is best fit with a single power law in DM-only simulations, but shows a flattening within ≈0.1Rvir for NIHAO for total masses M > 1011M. Finally, the global velocity distribution of DMis 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.

    Original languageEnglish (US)
    Pages (from-to)663-680
    Number of pages18
    JournalMonthly Notices of the Royal Astronomical Society
    Volume462
    Issue number1
    DOIs
    StatePublished - Oct 11 2016

    Fingerprint

    space density
    galactic evolution
    density distribution
    halos
    dark matter
    astrophysics
    velocity distribution
    simulation
    star formation
    solar neighborhood
    distribution
    project
    flattening
    stellar mass
    massive stars
    supernovae
    power law
    hydrodynamics
    galaxies
    cooling

    Keywords

    • Galaxies: evolution
    • Galaxies: interactions
    • Galaxies: structure
    • Galaxy: disc
    • Galaxy: evolution
    • Galaxy: structure
    • Methods: numerical

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    NIHAO project II : Halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations. / Butsky, Iryna; Maccio, Andrea; Dutton, Aaron A.; Wang, Liang; Obreja, Aura; Stinson, Greg S.; Penzo, Camilla; Kang, Xi; Keller, Ben W.; Wadsley, James.

    In: Monthly Notices of the Royal Astronomical Society, Vol. 462, No. 1, 11.10.2016, p. 663-680.

    Research output: Contribution to journalArticle

    Butsky, I, Maccio, A, Dutton, AA, Wang, L, Obreja, A, Stinson, GS, Penzo, C, Kang, X, Keller, BW & Wadsley, J 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, vol. 462, no. 1, pp. 663-680. https://doi.org/10.1093/mnras/stw1688
    Butsky, Iryna ; Maccio, Andrea ; Dutton, Aaron A. ; Wang, Liang ; Obreja, Aura ; Stinson, Greg S. ; Penzo, Camilla ; Kang, Xi ; Keller, Ben W. ; Wadsley, James. / NIHAO project II : Halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations. In: Monthly Notices of the Royal Astronomical Society. 2016 ; Vol. 462, No. 1. pp. 663-680.
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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: 106 ≲ M*/M⊙ ≲ 1011(109.5 ≲ Mhalo/M⊙ ≲ 1012.5). When compared to DM-only simulations, the NIHAO haloes have similar shapes at the virial radius, Rvir, 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/σ3) is best fit with a single power law in DM-only simulations, but shows a flattening within ≈0.1Rvir for NIHAO for total masses M > 1011M⊙. Finally, the global velocity distribution of DMis 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.",
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    T2 - Halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations

    AU - Butsky, Iryna

    AU - Maccio, Andrea

    AU - Dutton, Aaron A.

    AU - Wang, Liang

    AU - Obreja, Aura

    AU - Stinson, Greg S.

    AU - Penzo, Camilla

    AU - Kang, Xi

    AU - Keller, Ben W.

    AU - Wadsley, James

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    N2 - 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: 106 ≲ M*/M⊙ ≲ 1011(109.5 ≲ Mhalo/M⊙ ≲ 1012.5). When compared to DM-only simulations, the NIHAO haloes have similar shapes at the virial radius, Rvir, 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/σ3) is best fit with a single power law in DM-only simulations, but shows a flattening within ≈0.1Rvir for NIHAO for total masses M > 1011M⊙. Finally, the global velocity distribution of DMis 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.

    AB - 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: 106 ≲ M*/M⊙ ≲ 1011(109.5 ≲ Mhalo/M⊙ ≲ 1012.5). When compared to DM-only simulations, the NIHAO haloes have similar shapes at the virial radius, Rvir, 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/σ3) is best fit with a single power law in DM-only simulations, but shows a flattening within ≈0.1Rvir for NIHAO for total masses M > 1011M⊙. Finally, the global velocity distribution of DMis 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.

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    KW - Galaxies: interactions

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    KW - Galaxy: disc

    KW - Galaxy: evolution

    KW - Galaxy: structure

    KW - Methods: numerical

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