The evolution of the spatially-resolved metal abundance in galaxy
  clusters up to z=1.4
  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 $Z(z) = Z_0 (1+z)^{-\gamma}$ 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 $\gamma$
is significantly different from zero in the inner cluster regions ($\gamma =
1.6 \pm 0.2$) 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 $Z(r,z)=Z_0 (1+(r/0.15 R500)^2)^{-\beta} (1+z)^{-\gamma}$, with $(Z_0,
\beta, \gamma) = (0.83 \pm 0.13, 0.55 \pm 0.07, 1.7 \pm 0.6)$ 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.
