Cosmology and astrophysics from relaxed galaxy clusters – V. Consistency with cold dark matter structure formation

Abstract

This is the fifth in a series of papers studying the astrophysics and cosmology of massive, dynamically relaxed galaxy clusters. Our sample comprises 40 clusters identified as being dynamically relaxed and hot in Papers I and II of this series. Here we use constraints on cluster mass profiles from X-ray data to test some of the basic predictions of cosmological structure formation in the Cold Dark Matter (CDM) paradigm. We present constraints on the concentration-mass relation for massive clusters, finding a power-law mass dependence with a slope of κ m = −0.16 ± 0.07, in agreement with CDM predictions. For this relaxed sample, the relation is consistent with a constant as a function of redshift (power-law slope with 1 + z of κ ζ = −0.17 ± 0.26), with an intrinsic scatter of σ ln c = 0.16 ± 0.03. We investigate the shape of cluster mass profiles over the radial range probed by the data (typically ∼ 50 kpc-1 Mpc), and test for departures from the simple Navarro, Frenk & White (NFW) form, for which the logarithmic slope of the density profile tends to −1 at small radii. Specifically, we consider as alternatives the generalized NFW (GNFW) and Einasto parametrizations. For the GNFW model, we find an average value of (minus) the logarithmic inner slope of β = 1.02 ± 0.08, with an intrinsic scatter of σ β = 0.22 ± 0.07, while in the Einasto case we constrain the average shape parameter to be α = 0.29 ± 0.04 with an intrinsic scatter of σ α = 0.12 ± 0.04. Our results are thus consistent with the simple NFW model on average, but we clearly detect the presence of intrinsic, cluster-to-cluster scatter about the average.

The Three Hundred project: a large catalogue of theoretically modelled galaxy clusters for cosmological and astrophysical applications

“…The fitting parameters α and β are listed in table 5. It is evident that the c − M relation from our hydrosimulated clusters is closer to the observational results from Merten et al (2015); Okabe & Smith (2016); Biviano et al (2017) than those from Mantz et al (2016); Groener et al (2016). The c − M relation from the Gadget-MUSIC run is slightly higher than from the Gadget-X run and it is in better agreement with observational results which have lower concentrations.…”

“…Left panel: The concentration-halo mass relation for the relaxed galaxy clusters from the two hydrodynamical simulation runs compared with various observational results. As indicated in the legend, thick lines with different styles show the best fit results from recent observational data obtained with different methods(Merten et al 2015;Mantz et al 2016;Okabe & Smith 2016;Groener et al 2016;Biviano et al 2017). Symbols show the median values with the 16 th -84 th percentile error-bars from the hydro simulations: circles and stars (red filled symbols for Gadget-MUSIC and blue open symbols for Gadget-X) for the concentration derived by fitting the density profile up to two inner radii (34 h −1 kpc and 0.05 R 200 , see text for details).…”

Dependency of halo concentration on mass, redshift and fossilness in Magneticum hydrodynamic simulations

“…The low mass regime of the plot shows observations of galaxies from the DiskMass survey from Martinsson et al (2013). A B z = 0 6.25 ± 0.07 −0.121 ± 0.004 z = 0.5 5.79 ± 0.07 −0.122 ± 0.004 z = 1 5.26 ± 0.08 −0.123 ± 0.007 z = 1.5 5.36 ± 0.07 −0.117 ± 0.006 z = 2 5.37 ± 0.07 −0.097 ± 0.006 z = 0 − 2 5.74 ± 0.07 −0.104 ± 0.004 3 · 10 13 − 2 · 10 14 h −1 0.09 5.4 lensing from CFHTLenS Correa et al (2015) N/A −0.08 3.8 semi-analytical model Merten et al (2015) 5 · 10 14 − 2 · 10 15 −0.32 ± 0.18 N/A lensing+X rays on CLASH data Mantz et al (2016) 5 · 10 14 − 2 · 10 15 −0.15 N/A lensing and X-ray from Chandra and ROSAT Groener et al (2016) ∼ 10 (Merten et al 2015). It must be taken into account that the galaxies from the DiskMass survey are a restricted subsample of a very large initial sample.…”

Spatial distribution of metals in the ICM: evolution of the iron excess in relaxed galaxy clusters

“…Clusters of galaxies are the largest gravitationally-bound systems in the universe. Growing through gravitational instability from the fluctuations in the primordial density field (see Kravtsov & Borgani 2012, and references therein), not only can their abundance be used to trace the cosmic evolution thanks to a strong dependence on the cosmological parameters (Allen et al 2011;Mantz et al 2016), but they can also be considered approximately as closed boxes which retain the imprints of the evolution of the member galaxies and the surrounding intracluster medium (ICM, see, e.g., Böhringer & Werner 2010). The X-ray emitting ICM is by far the dominant baryonic component across the full range of virial masses of galaxy groups and clusters (Lin et al 2012), E-mail: liuang@arcetri.astro.it (A. Liu) † E-mail: ptozzi@arcetri.astro.it (P. Tozzi) and is constituted of a hot, diffuse, optically-thin plasma in collisional equilibrium, enriched by heavy elements produced mainly by supernovae (SNe) explosions.…”