The shape of dark matter haloes : dependence on mass, redshift, radius and formation

By B. Allgood, R. Flores, Joel R. Primack, Andrey V. Kravtsov, Risa Wechsler, A. Faltenbacher, James S. Bullock. 2005

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Using six high-resolution dissipationless simulations with a varying box size in a flat Lambda cold dark matter (ACDM) universe, we study the mass and redshift dependence of dark matter halo shapes for M vir = 9.0 x 10" - 2.0 x 10 14 h -1 M ⊙ , over the redshift range z = 0-3, and for two values of σ 8 = 0.75 and 0.9. Remarkably, we find that the redshift, mass and σ 8 dependence of the mean smallest-to-largest axis ratio of haloes is well described by the simple power-law relation (s) = (0.54 ± 0.02)(M vir /M * ) -0.050±0.003 , where s is measured at 0.3R vir , and the z and σ 8 dependences are governed by the characteristic non-linear mass, M * = M * (z, σ 8 ). We find that the scatter about the mean s is well described by a Gaussian with a ∼ 0.1, for all masses and redshifts. We compare our results to a variety of previous works on halo shapes and find that reported differences between studies are primarily explained by differences in their methodologies. We address the evolutionary aspects of individual halo shapes by following the shapes of the haloes through ∼100 snapshots in time. We determine the formation scalefactor a c as defined by Wechsler et al. and find that it can be related to the halo shape at z = 0 and its evolution over time.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c95b10e17ebb9edc9818a8095ecfcffd87546577

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Citations in the corpus

DARK MATTER HALOS IN THE STANDARD COSMOLOGICAL MODEL: RESULTS FROM THE BOLSHOI SIMULATION (2010, background): “…for determining the dependence of halo concentration cvir ≡ Rvir/rs and halo shape on halo mass and redshift (Bullock et al. 2001; Zhao et al. 2003; Allgood et al. 2006; Neto et al. 2007; Macciò et al. 2008), and also for determining the dependence of the concentration of halos on their mass…”
Cosmological simulations with self-interacting dark matter – II. Halo shapes versus observations (2012, methodology): “Allgood et al. (2006) find that halos that form earlier are more spherical than halos that form later, which is attributed to directional merging, and more generally to the highly non-spherically-symmetrical way in which halos form and accrete.”
The shape of dark matter haloes in the Aquarius simulations: evolution and memory (2011, methodology): “The solid white ellipses correspond to our new density-based method, while the dashed ones are for the inertia tensor method described by Allgood et al. (2006).”
Bar formation and evolution in disc galaxies with gas and a triaxial halo: morphology, bar strength and halo properties (2012, background): “Yet cosmological simulations (e.g. Dubinski & Carlberg 1991; Jing & Suto 2002; Bailin & Steinmetz 2005; Allgood et al. 2006; Novak et al. 2006; Vera-Ciro et al. 2011; Schneider, Frenk & Cole 2012) have shown that in cases with no baryons the haloes are strongly triaxial, as could be expected by the…”
The Kinematic Structure of Merger Remnants (2006, result): “…tensor based upon the most bound stellar particles but alternatives are spherical or ellipsoidal windows which may be interatively adjusted until the measured shape and selected aperture agree (see e.g., Allgood et al. 2006, for survey of different methods and recent results from the literature).”
The evolution of dark matter halo properties in clusters, filaments, sheets and voids (2007, result): “Over a large range of masses, haloes at z = 1.05 are however less spherical than haloes of similar mass at z = 0; Avila-Reese et al. (2005) and Allgood et al. (2006) find a similar result in their analyses.”
Concentration, spin and shape of dark matter haloes: Scatter and the dependence on mass and environment (2006, methodology): “We find that more massive haloes are on average more flattened (more prolate), in qualitative agreement with previous studies (Jing & Suto 2002; Bailin & Steinmetz 2005; Kasun & Evrard 2005; Allgood et al. 2006).”
Halo and subhalo demographics with Planck cosmological parameters: Bolshoi–Planck and MultiDark–Planck simulations (2016, methodology): “The clustering properties of halos are also different below and above MC (e.g., Wechsler et al. 2006), and halo properties such as their triaxial shapes scale with MC (e.g., Allgood et al. 2006).”
Properties of dark matter haloes in clusters, filaments, sheets and voids (2006, background): “The overall mass dependence of S and T is in good agreement with previous studies (e.g. Allgood et al. 2006; Altay, Colberg & Croft 2006; Bett et al. 2006; Macciò et al. 2006).”
The diversity and similarity of simulated cold dark matter haloes (2008, background): “…1997, hereafter NFW), (2) strongly triaxial shapes, with a slight preference for nearly prolate systems (e.g., Frenk et al., 1988; Jing & Suto, 2002; Allgood et al., 2006; Hayashi et al., 2007), (3) abundant, but non-dominant, substructure (Klypin et al., 1999; Moore et al., 1999a; Ghigna et al.,…”
ON THE ACCURACY OF WEAK-LENSING CLUSTER MASS RECONSTRUCTIONS (2010, methodology): “We fit a power-law to the mean value ofSas a function of M500c (a similar relation was used in Allgood et al. 2006).”
Lensing and x-ray mass estimates of clusters (simulations) (2012, unknown): “Studies based on simulations showed that clusters forming in a CDM framework are generally prolate systems (Shaw et al. 2006; Allgood et al. 2006; Lau et al. 2011).”
Galactic stellar haloes in the CDM model (2009, methodology): “These were determined using the iterative procedure described by Allgood et al. (2006), which attempts to fit the shapes of self-consistent ‘isodensity’ contours.”