Iron as a tracer in galaxy clusters and groups

We present the analysis of deep X-ray observations of 10 massive galaxy clusters at redshifts $1.05 < z < 1.71$, with the primary goal of measuring the metallicity of the intracluster medium (ICM) at intermediate radii, to better constrain models of the metal enrichment of the intergalactic medium. The targets were selected from X-ray and Sunyaev-Zel'dovich (SZ) effect surveys, and observed with both the \textit{XMM-Newton} and \textit{Chandra} satellites. For each cluster, a...

Using the guidelines on SN element production provided by XMM-Newton, we summarize the results of ASCA observations on the element abundance in groups and clusters of galaxies. We show that while the metal production in groups could be described by a stellar population with a standard local IMF, clusters of galaxies require a more top-heavy IMF. We attribute an excess heavy element production to an IMF evolution with redshift. Dating the galaxy formation in clusters by observ...

Most of the metals (elements heavier than helium) ever produced by stars in the member galaxies of galaxy clusters currently reside within the hot, X-ray emitting intra-cluster gas. Observations of X-ray line emission from this intergalactic medium have suggested a relatively small cluster-to-cluster scatter outside of the cluster centers and enrichment with iron out to large radii, leading to the idea that the metal enrichment occurred early in the history of the Universe. M...

Clusters of galaxies provide a closed box within which one can determine the chemical evolution of the gaseous baryons with cosmic time. We studied this metallicity evolution in the hot X-ray emitting baryons through an analysis of XMM-Newton observations of 29 galaxy clusters in the redshift range 0.3 < z < 1.3. Taken alone, this data set does not show evidence for significant evolution. However, when we also include a comparable sample of 115 clusters observed with Chandra ...

As building blocks of dust, rocky planets, and even complex life, the chemical elements heavier than hydrogen (H) and helium (He) - called "metals" in astronomy - play an essential role in our Universe and its evolution. Up to Fe and Ni, these metals are known to be created by stars and stellar remnants via nuclear fusion and to be ejected into their immediate surroundings to enrich new stellar generations. A spectacular finding, however, is that these processed elements are ...

Emission lines in X-ray spectra of clusters of galaxies reveal the presence of heavy elements in the diffuse hot plasma (the Intra Cluster Medium, or ICM) in virial equilibrium in the dark matter potential well. The relatively simple physical state of the ICM allows us to estimate, with good accuracy, its thermodynamical properties and chemical abundances. These measures put strong constraints on the interaction processes between the galaxies and the surrounding medium, and h...

We have analyzed the ASCA data of 29 nearby clusters of galaxies systematically, and obtained temperatures, iron abundances, and X-ray luminosities of their intracluster medium (ICM). We also estimate ICM mass using the beta model, and then evaluate iron mass contained in the ICM and derive the total gravitating mass. This gives the largest and most homogeneous information about the ICM derived only by the ASCA data. We compare these values with those of distant clusters whos...

The hot gas that fills the space between galaxies in clusters is rich in metals. In their large potential wells, galaxy clusters accumulate metals over the whole cluster history and hence they retain important information on cluster formation and evolution. We use a sample of 5 cool core clusters to study the distribution of metals in the ICM. We investigate whether the X-ray observations yield good estimates for the metal mass and whether the heavy elements abundances are co...

Using Chandra X-ray data of a sample of 15 X-ray bright galaxy groups, we present preliminary results of a coherent study of the radial distribution of metal abundances in the hot gas in groups. The iron content in group outskirts is found to be lower than in clusters by a factor of ~2, despite showing mean levels in the central regions comparable to those of clusters. The abundance profiles are used to constrain the contribution from supernovae type Ia and II to the chemical...

The large scale structure of the present Universe is determined by the growth of dark matter density fluctuations and by the dynamical action of dark energy and dark matter. While much progress has been made in recent years in constraining the cosmological parameters, and in reconstructing the evolution in the large--scale structure of the dark matter distribution, we still lack an understanding of the evolution of the baryonic component of the Universe. Located at nodes of...