Virial Scaling of Massive Dark Matter Halos: Why Clusters Prefer a High Normalization Cosmology

By August E. Evrard, J. Bialek, Michael T. Busha, M. White, Salman Habib, Katrin Heitmann, M. Warren, E. Rasia, G. Tormen, L. Moscardini and 7 more. 2007

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We present a precise estimate of the bulk virial scaling relation of halos formed via hierarchical clustering in an ensemble of simulated cold dark matter cosmologies. The result is insensitive to cosmological parameters; the presence of a trace, dissipationless gas component; and numerical resolution down to a limit of ~1000 particles. The dark matter velocity dispersion scales with total mass as log [σDM(M,z)] = = log(1082.9 ± 4.0 km s−1) + (0.3361 ± 0.0026)log[h(z)M200/1015 M☉], with h(z) being the dimensionless Hubble parameter. At fixed mass, the velocity dispersion likelihood is nearly lognormal, with scatter σln σ = 0.0426 ± 0.015, except for a tail with higher dispersions containing 10% of the population that are merger transients. We combine this relation with the halo mass function in ΛCDM models and show that a low normalization condition, S8 = σ8(Ωm/0.3)0.35 = 0.69, favored by recent WMAP and SDSS analysis requires that galaxy and gas-specific energies in rich clusters be 50% larger than that of the underlying dark matter. Such large energetic biases are in conflict with the current generation of direct simulations of cluster formation. A higher normalization, S8 = 0.80, alleviates this tension and implies that the hot gas fraction within r500 is , a value consistent with recent Sunyaev-Zel’dovich observations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/a2b3e4904fd05bd1022ce5876855bfcad27b3ec9

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Citations in the corpus

Mass, metal, and energy feedback in cosmological simulations (2007, background): “Note that σ8 is somewhat higher than the WMAP3favored value of 0.75, owing to observations suggesting that it may be as high as 0.9 (e.g. Rozo et al. 2007; Evrard et al. 2008).”
The universality of the virial halo mass function and models for non-universality of other halo definitions (2015, background): “Many cosmological constraints have been obtained from cluster counts (Vikhlinin et al. 2009; Rozo et al. 2010; Planck Collaboration et al. 2013a) and other galaxy cluster properties (Evrard et al. 2008; Ettori et al. 2009; Giocoli et al. 2012c).”
DEPENDENCE OF THE OUTER DENSITY PROFILES OF HALOS ON THEIR MASS ACCRETION RATE (2014, methodology): “First, it justifies using radii defined with respect to the critical density in defining cluster masses and observable properties, as is often done in galaxy cluster studies (e.g., Evrard et al. 2008).”
The BAHAMAS project: Calibrated hydrodynamical simulations for large-scale structure cosmology (2016, methodology): “These relations are virtually identical to that previously derived by Evrard et al. (2008) based on a suite of dark matter-only simulations (after converting their masses from M200,c into M500,c).”
Cosmological Parameters from Observations of Galaxy Clusters (2011, background): “While the relation between the three-dimensional dark matter velocity dispersion and mass is predicted to be tight (Evrard et al. 2008), velocity anisotropy and projection effects cause the one-dimensional velocity dispersion to exhibit larger scatter (10 − 15%, implying a scatter in mass at fixed…”
DARK MATTER HALO PROFILES OF MASSIVE CLUSTERS: THEORY VERSUS OBSERVATIONS (2011, background): “Nevertheless, as shown by Evrard et al. (2008), cluster-scale systems with mass greater than 1014h−1M⊙ are dominated by large, primary halos – satellite halos carrying only∼ 10% of the mass – and possess a well-defined and regular virial relation.”
THE COYOTE UNIVERSE. II. COSMOLOGICAL MODELS AND PRECISION EMULATION OF THE NONLINEAR MATTER POWER SPECTRUM (2009, background): “(A color version of this figure is available in the online journal.) for constraints from combined CMB and large-scale structure data, and Evrard et al. 2008 for an extended discussion of recent results).”
The Observed Growth of Massive Galaxy Clusters I: Statistical Methods and Cosmological Constraints (2009, result): “Motivated by the results of Evrard et al. (2008), we have defined the scaling relations for quantities within r500, which also corresponds to our measurements of mass, luminosity and temperature from follow-up observations (Paper II).”
CONSTRAINING THE SCATTER IN THE MASS–RICHNESS RELATION OF maxBCG CLUSTERS WITH WEAK LENSING AND X-RAY DATA (2008, methodology): “These assigned masses are then turned into velocity dispersions using the scaling relation from Evrard et al. (2008).”
MEASURING THE ULTIMATE HALO MASS OF GALAXY CLUSTERS: REDSHIFTS AND MASS PROFILES FROM THE HECTOSPEC CLUSTER SURVEY (HeCS) (2012, background): “The dashed line in Figure 7 shows the M200 − σp relation found by Evrard et al. (2008) for dark matter particles in simulated dark matter haloes.”
The relation between velocity dispersion and mass in simulated clusters of galaxies: dependence on the tracer and the baryonic physics (2013, methodology): “Following Evrard et al. (2008), we use the onedimensional velocity dispersion σ1D ≡ σ200/ √ 3.”
New constraints on dark energy from the observed growth of the most X-ray luminous galaxy clusters (2007, methodology): “We have chosen to constrain the relation at an overdensity of ∆ = 500 in order to match our data (Section 3.1.1), and because the simulations of Evrard et al. (2008) indicate that the virial relations have lower scatter at this overdensity compared with higher overdensities.”
The Atacama Cosmology Telescope: Sunyaev-Zel'dovich selected galaxy clusters at 148 GHz from three seasons of data (2013, methodology): “15,6 motivated by the results of [31] as described in section 3.”