Iron as a tracer in galaxy clusters and groups

We present the first large sample of accurate iron abundances and temperatures for clusters at redshifts greater than 0.14. We find that the Fe abundance shows little or no evolution out to redshift 0.3. This and the early formation epoch of elliptical galaxies in clusters indicate that most of the enrichment of the intracluster medium occurred at redshifts greater than 1. If clusters represent fair samples of the universe, then global metal production is 2-5 times greater th...

We present a study on the origin of the metallicity evolution of the intra-cluster medium (ICM) by applying a semi-analytic model of galaxy formation to N-body/SPH (smoothed particle hydrodynamic) non-radiative numerical simulations of clusters of galaxies. The semi-analytic model includes gas cooling, star formation, supernovae feedback and metal enrichment, and is linked to the diffuse gas of the underlying simulations so that the chemical properties of gas particles are dy...

Clusters of galaxies allow a direct estimate of the metallicity and metal production yield on the largest scale so far. The ratio of the total iron mass in the ICM to the total optical luminosity of the cluster (the iron mass-to-light-ratio) is the same for all clusters which ICM is hotter than $\sim 2$ keV, and the elemental proportions (i.e. the [$\alpha$/Fe] ratio) appear to be solar. From these evidences it is argued that both the IMF as well the relative contributions of...

The nature of star formation and Type Ia supernovae (SNIa) in galaxies in the field and in rich galaxy clusters are contrasted by juxtaposing the build-up of heavy metals in the universe inferred from observed star formation and supernovae rate histories with data on the evolution of Fe abundances in the intracluster medium (ICM). Models for the chemical evolution of Fe in these environments are constructed, subject to observational constraints, for this purpose. While models...

We compile X-ray data of clusters of galaxies at a wide range of redshift $z=0.0\sim1.0$ and compare X-ray luminosities, gas masses, iron abundances and iron masses of nearby clusters and those of distant clusters as a function of plasma temperature. All the date presented in this paper have been obtained only with \ASCA and/or \ROSAT. No evidence for a change in the \KT -\LX\ relationship or \KT - iron abundance at $z<0.6$ is found. No significant change in \KT -\LX relation...

We present a Chandra analysis of the X-ray spectra of 56 clusters of galaxies at $z>0.3$, which cover a temperature range of $3> kT > 15$ keV. Our analysis is aimed at measuring the iron abundance in the ICM out to the highest redshift probed to date. We find that the emission-weighted iron abundance measured within $(0.15-0.3) R_{vir}$ in clusters below 5 keV is, on average, a factor of $\sim2$ higher than in hotter clusters, following $Z(T)\simeq 0.88 T^{-0.47} Z_\odot$, wh...

This work measures the evolution of the iron content in galaxy clusters by a rigorous analysis of the data of 130 clusters at 0.1<z<1.3. This task is made difficult by a) the low signal-to-noise ratio of abundance measurements and the upper limits, b) possible selection effects, c) boundaries in the parameter space, d) non-Gaussian errors, e) the intrinsic variety of the objects studied, and f) abundance systematics. We introduce a Bayesian model to address all these issues a...

Results from a large set of hydrodynamical SPH simulations of galaxy clusters in a flat LCDM cosmology are used to investigate the metal enrichment and heating of the ICM. The physical modeling of the gas includes radiative cooling, star formation, energy feedback and metal enrichment that follow from the explosions of SNe of type II and Ia. The metallicity dependence of the cooling function is also taken into account. For a fiducial set of model prescriptions the results ind...

We present a Chandra analysis of the X-ray spectra of 56 clusters of galaxies at z>0.3, which cover a temperature range of 3>kT>15 keV. Our analysis is aimed at measuring the iron abundance in the ICM out to the highest redshift probed to date. We find that the emission-weighted iron abundance measured within (0.15-0.3)R_vir in clusters below 5 keV is, on average, a factor of ~2 higher than in hotter clusters, following Z(T)~0.88T^-(0.47)Z_o, which confirms the trend seen in ...

Hydrodynamical SPH simulations of galaxy clusters are used to investigate the metal enrichment of the intracluster medium. The final metallicity abundances of the simulated clusters are determined according to the numerical resolution and a number of model parameters. For a fiducial set of model prescriptions the results of the simulations indicate iron abundances in broad agreement with data. Final X-ray properties are not sensitive to the heating of the ICM. This supports a...