The evolution of the spatially resolved metal abundance in galaxy clusters up toz= 1.4

Abstract

Context. We present the combined analysis of the metal content of 83 objects in the redshift range 0.09−1.39, and spatially resolved in the three bins (0−0.15, 0.15−0.4, >0.4) R 500 , as obtained with similar analysis using XMM-Newton data in our previous two papers. Aims. By combining these two large data sets, we investigate the relations between abundance, temperature, radial position and redshift holding in the intracluster medium. Methods. We fit functional forms to the combination of the different physical quantities of interest, i.e., intracluster medium (ICM) metal abundance, radius, and redshift. We use the pseudo-entropy ratio to separate the cool core (CC) cluster population, where the central gas density tends to be relatively higher, cooler and more metal rich, from the non-cool core systems. Results. The average, redshift-independent, metal abundance measured in the three radial bins decreases moving outwards, with a mean metallicity in the core that is even three (two) times higher than the value of 0.16 times the solar abundance in Anders & Grevesse (1989, Geochim. Cosmochim. Acta, 53, 197) estimated at r > 0.4 R 500 in CC (NCC) objects. We find that the values of the emission-weighted metallicity are well fitted by the relation Z(z) = Z 0 (1 + z) −γ at the given radius. A significant scatter, intrinsic to the observed distribution and of the order of 0.05−0.15, is observed below 0.4 R 500 . The nominal best-fit value of γ is significantly different from zero (>3σ) in the inner cluster regions (γ = 1.6 ± 0.2) and in CC clusters only. These results are also confirmed with a bootstrap analysis, which provides a still significant negative evolution in the core of CC systems (P > 99.9 per cent, when counting the number of random repetitions, which yields γ > 0). No redshift evolution is observed when regions above the core (r > 0.15 R 500 ) are considered. A reasonable good fit of both the radial and redshift dependence is provided from the functional form Z(r, z) = Z 0 (1 + (r/0.15 R 500 ) 2 ) −β (1 + z) −γ , with (Z 0 , β, γ) = (0.83 ± 0.13, 0.55 ± 0.07, 1.7 ± 0.6) in CC clusters and (0.39 ± 0.04, 0.37 ± 0.15, 0.5 ± 0.5) for NCC systems. Conclusions. Our results represent the most extensive study of the spatially resolved metal distribution in the cluster plasma as function of redshift. Our study defines the limits that numerical and analytic models describing the metal enrichment in the ICM have to meet.

Uniform Contribution of Supernova Explosions to the Chemical Enrichment of Abell 3112 out to R200

“…The statistical errors corresponding to D = C 1 with the systematic uncertainties described in Section 4 are added to the total error budget shown in the figure. The ratio of the SN Ia to SN cc is fairly uniform from the core to the outskirts. redshift Perseus and Virgo clusters (Werner et al 2013;Simionescu et al 2015), and the early enrichment timescale is consistent with studies of mass-selected samples of galaxy clusters with redshift < < z 0 1.5 (Ettori et al 2015;McDonald et al 2016). …”

Increasing Black Hole Feedback-induced Quenching with Anisotropic Thermal Conduction

“…While the gas phase metallicities in the outer parts of the cluster are quite similar in both runs, the difference between them (in both the mean value and dispersion) within the core of the cluster (  r 100 kpc) is quite striking. The Cond run reproduces the observational estimates of the metallicity profiles in clusters more faithfully (Leccardi & Molendi 2008, gold shaded region; Ettori et al 2015, solid black curve).…”

Rhapsody-G simulations – II. Baryonic growth and metal enrichment in massive galaxy clusters

“…This fact is a consequence of the mixing that leads to flattened entropy profiles. Comparison to the observational data of Ettori et al (2015) shows that our simulated clusters have metallicities a factor Á 3 smaller than real cluster both for CCs and NCCs; observations also show that the dichotomy between CCs and NCCs central metallicities is stronger in real clusters than in our simulated sample. In the SPH simulations by Rasia et al (2015) this discrepancy is not observed; its origin in our simulations is unclear, however we are planning to investigate on this issue by performing explicit comparison of AMR and SPH simulations with the same initial conditions and similar sub-grid models in a future paper.…”

“…Figure 9 shows the differential ICM metallicity profile for the R4K simulations at redshift z " 0 when the cluster population is divided in cool core and non-cool core clusters as in Hahn et al (2015). In this figure, the ICM metallicites have been multiplied by a factor 3 to facilitate comparison to the observational results of Ettori et al 2015 (dashed lines; the sample is an extension of the one used by Leccardi & Molendi 2008). Even if the scatter between the haloes (shaded areas) is large it is possible to appreciate how metals are re-distributed differently depending on whether the clusters have a cool core or not.…”

“…The typical 1-σ scatter among the haloes is represented by the blue and red shaded areas for the cool core and non-cool core clusters, respectively. The simulations are compared to the fits to observational data for CC (blue dot-dashed line) and NCC (red dotted line) clusters from Ettori et al (2015).…”