The diversity and similarity of simulated cold dark matter haloes

By J. Navarro, A. Ludlow, Volker Springel, Jie-Shuang Wang, M. Vogelsberger, Simon D. M. White, Adrian Jenkins, Carlos S. Frenk, A. Helmi. 2008

642 citations recorded by the source corpus.

We study the mass, velocity dispersion and anisotropy profiles of Lambda cold dark matter (Lambda CDM) haloes using a suite of N-body simulations of unprecedented numerical resolution. The Aquarius Project follows the formation of six different galaxy-sized haloes simulated several times at varying numerical resolution, allowing numerical convergence to be assessed directly. The highest resolution simulation represents a single dark matter halo using 4.4 billion particles, of which 1.1 billion end up within the virial radius. Our analysis confirms a number of results claimed by earlier work, and clarifies a few issues where conflicting claims may be found in the recent literature. The mass profile of Lambda CDM haloes deviates slightly but systematically from the form proposed by Navarro, Frenk & White. The spherically averaged density profile becomes progressively shallower inwards and, at the innermost resolved radius, the logarithmic slope is gamma equivalent to - d ln /d ln r less than or similar to 1. Asymptotic inner slopes as steep as the recently claimed proportional to r-1.2 are clearly ruled out. The radial dependence of gamma is well approximated by a power law, gamma proportional to r alpha (the Einasto profile). The shape parameter, alpha, varies slightly but significantly from halo to halo, implying that the mass profiles of Lambda CDM haloes are not strictly universal: different haloes cannot, in general, be rescaled to look identical. Departures from similarity are also seen in velocity dispersion profiles and correlate with those in density profiles so as to preserve a power-law form for the spherically averaged pseudo-phase-space density, /Sigma 3 proportional to r-1.875. The index here is identical to that of Bertschinger's similarity solution for self-similar infall on to a point mass from an otherwise uniform Einstein-de Sitter universe. The origin of this striking behaviour is unclear, but its robustness suggests that it reflects a fundamental structural property of Lambda CDM haloes. Our conclusions are reliable down to radii below 0.4 per cent of the virial radius, providing well-defined predictions for halo structure when baryonic effects are neglected, and thus an instructive theoretical template against which the modifications induced by the baryonic components of real galaxies can be judged.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/449b6bfc036091959484773ce58825075dc42b17

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Citations in the corpus

The masses and density profiles of halos in a LCDM galaxy formation simulation (2014, background): “…between halo mass and concentration has been studied by many authors (e.g. AvilaReese et al. 1999; Jing 2000; Bullock et al. 2001; Eke, Navarro & Steinmetz 2001; Zhao et al. 2003; Neto et al. 2007; Duffy et al. 2008; Gao et al. 2008; Navarro et al. 2010; Dutton & Macciò 2014; Ludlow et al. 2014).”
Co-formation of the disc and the stellar halo (2018, methodology): “As demonstrated by Navarro et al. (2010), in the Aquarius suite of simulations, β starts nearly isotropic in the centre of the galaxy, it reaches β ∼ 0.2 around the Solar radius and keeps growing to β ∼ 0.5 at >100 kpc, before falling again to zero around the virial radius.”
The dependence of dark matter profiles on the stellar-to-halo mass ratio: a prediction for cusps versus cores (2013, positive): “A prediction of pure DM collisionless simulationsis that dark matter density increases asρ∝ r−1 toward the halo center (Navarro et al. 1996; Springel et al. 2008; Navarro et al. 2010).”
Dynamical modelling of the galactic bulge and bar: the Milky Way's pattern speed, stellar and dark matter mass distribution (2016, methodology): “Recent studies of dark matter simulations such as Navarro et al. (2010) showed that the innermost regions of dark matter halos were better represented by the Einasto density profile (Einasto 1965) than by the NFW profile.”
The Phoenix Project: the dark side of rich galaxy clusters (2012, methodology): “The code is identical to that used for the Aquarius Project (Springel et al. 2008b).”
Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies (2012, background): “…simulations predict that DM halos should follow a quasi– universal Einasto profile (Navarro et al. 1996b; Moore et al. 1999; Reed et al. 2005; Macciò et al. 2009; Stadel et al. 2009; Navarro et al. 2010), defined by a power law density profile ρ ∝ rα with −1.5 < α < −1 in their central regions.”
LoCuSS: Subaru Weak Lensing Study of 30 Galaxy Clusters (2009, background): “…matter (CDM) model of structure formation is that dark matter halos can be described by a universal mass density profile, as found by Navarro, Frenk, and White (1996, 1997, hereafter NFW; also see Moore et al. 1999; Fukushige & Makino 2001; most recently Navarro et al. 2010 and references therein).”
HIGH-RESOLUTION MASS MODELS OF DWARF GALAXIES FROM LITTLE THINGS (2015, background): “…R is the galaxy radius and α∼−1.0 (Moore 1994; Navarro et al. 1996b; Navarro et al. 1997; Moore et al. 1999; Ghigna et al. 2000; Klypin et al. 2001; Power et al. 2003; Stoehr et al. 2003; Navarro et al. 2004a; Diemand et al. 2008; Stadel et al. 2009; Navarro et al. 2010; Ishiyama et al. 2013 etc.).”
Tracing the dark matter sheet in phase space (2011, methodology): “These velocity dispersions differ quite significantly from the similarly termed quantities presented previously (e.g. Navarro et al. 2010, and references therein) .”
Galactic Searches for Dark Matter (2012, background): “To get an estimate of a theoretically-plausible prediction for the gamma-ray flux from the Galactic center region, consider an Einasto dark matter profile (Equation 50) with ρ−2 = 3.7× 105 M kpc −3 and r−2 = 16 kpc (Navarro et al., 2010).”
Halo concentrations in the standard LCDM cosmology (2011, methodology): “Halo profiles on average show systematic deviations from the NFW approximation and are better approximated with the Einasto profile (Navarro et al. 2004; Gao et al. 2008; Navarro et al. 2010).”
There's no place like home? Statistics of Milky Way-mass dark matter haloes (2009, background): “Navarro et al. (2010) have made a thorough study of the structure of the Aquarius halos at z = 0, concluding that their density profiles are not perfectly universal and therefore cannot be fully described by a model with two scale parameters but no shape parameter (such as NFW).”