The evolution of the spatially-resolved metal abundance in galaxy clusters up to z=1.4

S. Ettori; A. Baldi; I. Balestra; F. Gastaldello; S. Molendi; P. Tozzi

doi:10.1051/0004-6361/201425470

paper

The evolution of the spatially-resolved metal abundance in galaxy clusters up to z=1.4

arXiv:1504.02107 · doi:10.1051/0004-6361/201425470

Abstract

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 3 bins (0-0.15, 0.15-0.4, >0.4) R500, as obtained with similar analysis using XMM-Newton data in Leccardi & Molendi (2008) and Baldi et al. (2012). 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. The average, redshift-independent, metal abundance measured in the 3 radial bins decrease moving outwards, with a mean metallicity in the core that is even 3 (two) times higher than the value of 0.16 times the solar abundance in Anders & Grevesse (1989) estimated at r>0.4 R500 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 given radius. A significant scatter, intrinsic to the observed distribution and of the order of 0.05-0.15, is observed below 0.4 R500. The nominal best-fit value of $γ$ is significantly different from zero in the inner cluster regions ( $γ = 1.6 \pm 0.2$ ) and in CC clusters only. These results are confirmed also with a bootstrap analysis, which provides a still significant negative evolution in the core of CC systems (P>99.9 per cent). No redshift-evolution is observed when regions above the core (r > 0.15 R500) 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 $(Z_{0}, β, γ) = (0.83 \pm 0.13, 0.55 \pm 0.07, 1.7 \pm 0.6)$ in CC clusters and $(0.39 \pm 0.04, 0.37 \pm 0.15, 0.5 \pm 0.5)$ for NCC systems. Our results represent the most extensive study of the spatially-resolved metal distribution in the cluster plasma as function of redshift.

arXiv comment5 pages. Research Note accepted for publication in A&A

The evolution of the spatially-resolved metal abundance in galaxy clusters up to z=1.4

Abstract

References in corpus (27)

Cited by in corpus (44)