Dark matter halo shapes in the Auriga simulations

Abstract

We present shape measurements of Milky Way-sized dark matter halos at redshift $z=0$ in a suite of 30 zoom simulations from the Auriga project. We compare the results in full magnetohydrodynamics against dark matter only simulations and find a strong influence of baryons in making dark matter haloes rounder at all radii compared to their dark matter only counterparts. At distances $\lesssim 30$ kpc, rounder dark matter distributions correlate with extended massive stellar discs and low core gas densities. We measure the alignment between the halo and the disc shapes at different radii and find a high degree of alignment at all radii for most of the galaxies. In some cases the alignment significantly changes as a function of radius implying that the halo shape twists; this effect correlates with recently formed bulges and is almost absent in the dark matter only simulations. In a comparison against observational constraints we find that $20\%$ of halos in our sample are consistent with observational results derived from the Pal 5 stream that favours an almost spherical shape. Including baryons is a required element to achieve this level of agreement. In contrast, none of the simulations (neither dark matter only nor with baryons) match the constraints derived from the Sagittarius stream that favour an oblate dark matter halo.

arXiv commentMNRAS accepted, 13 pages, 11 figures

References in corpus (48)

• Planck 2013 results. XVI. Cosmological parameters
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• Triaxial Modeling of Halo Density Profiles with High-resolution N-body Simulations
• The Shape of Dark Matter Halos: Dependence on Mass, Redshift, Radius, and Formation
• The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time
• The Sagittarius Dwarf Galaxy: a Model for Evolution in a Triaxial Milky Way Halo
• A novel determination of the local dark matter density
• A direct dynamical measurement of the Milky Way's disk surface density profile, disk scale length, and dark matter profile at 4 kpc < R < 9 kpc
• Building up the Stellar Halo of the Galaxy
• The Effects of a Photoionizing UV Background on the Formation of Disk Galaxies
• Simulations of magnetic fields in isolated disk galaxies
• Unified Rotation Curve of the Galaxy -- Decomposition into de Vaucouleurs Bulge, Disk, Dark Halo, and the 9-kpc Rotation Dip --
• A Prescription for Building the Milky Way's Halo from Disrupted Satellites
• The Effect of Dissipation on the Shapes of Dark halos
• Galaxy-Induced Transformation of Dark Matter Halos
• A timing constraint on the (total) mass of the Large Magellanic Cloud
• The Causes of Halo Shape Changes Induced by Cooling Baryons: Disks Versus Substructures
• Evidence for dark matter in the inner Milky Way
• Magnetic field formation in the Milky Way-like disk galaxies of the Auriga project
• The shape of the inner Milky Way halo from observations of the Pal 5 and GD-1 stellar streams
• And yet it moves: The dangers of artificially fixing the Milky Way center of mass in the presence of a massive Large Magellanic Cloud
• Internal Alignment of the Halos of Disk Galaxies in Cosmological Hydrodynamic Simulations
• Two measures of the shape of the Milky Way's dark halo
• The Shape of Dark Matter Haloes in the Aquarius Simulations: Evolution and Memory
• Constraints on the shape of the Milky Way dark matter halo from the Sagittarius stream
• The impact of baryons on the spins and shapes of dark matter haloes
• Origin of chemically distinct discs in the Auriga cosmological simulations
• A 22 Degree Tidal Tail for Palomar 5
• The alignment and shape of dark matter, stellar, and hot gas distributions in the EAGLE and cosmo-OWLS simulations
• Shape of Dark Matter Haloes in the Illustris Simulation: Effects of Baryons
• The Cosmic Ballet II: Spin alignment of galaxies and haloes with large-scale filaments in the EAGLE simulation
• ZOMG-I. How the cosmic web inhibits halo growth and generates assembly bias
• Cosmic web alignments with the shape, angular momentum and peculiar velocities of dark matter haloes
• The geometry of phase mixing
• Tidal Stream Morphology as an Indicator of Dark Matter Halo Geometry: the Case of Palomar 5
• NIHAO project II: Halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations
• What's Up in the Milky Way? The Orientation of the Disc Relative to the Triaxial Halo
• The Sphericalization of Dark Matter Halos by Galaxy Disks
• The Sagittarius Stream and Halo Triaxiality
• Aurigaia: mock Gaia DR2 stellar catalogues from the Auriga cosmological simulations
• Alignments between galaxies, satellite systems and haloes
• Does the Sagittarius Stream constrain the Milky Way halo to be triaxial?
• Evolution of galactic planes of satellites in the EAGLE simulation
• Is the Dark Halo of the Milky Way Prolate?
• Progressively more prolate dark matter halo in the outer Galaxy as traced by flaring HI gas
• Dark Matter Response to Galaxy Assembly History
• We are not the 99 percent: quantifying asphericity in the distribution of Local Group satellites

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