Thermo-dynamic and chemical properties of the intra-cluster medium

Leccardi, A.; Rossetti, M.; Molendi, S.

doi:10.1051/0004-6361/200913094

Cited by 55 publications

(111 citation statements)

References 117 publications

(133 reference statements)

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“…Our results are consistent with the discussion in Leccardi et al (2010). The non-cD clusters in this paper include merging clusters in various stages, from heavily distorted morphologies to relatively relaxed ones without cool cores.…”

Section: Mixing Of the Icm In Non-cd Clusterssupporting

confidence: 92%

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Radial profiles of Fe abundance in the intracluster medium of nearby clusters observed withXMM-Newton

Matsushita

2011

A&A

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Aims. The abundances of Fe in the intracluster medium of nearby (z < 0.08) clusters were measured up to 0.3 ∼ 0.5r 180 . Methods. We analyzed 28 clusters of galaxies observed with XMM-Newton. We derived Fe abundances from the flux ratios of Fe lines to the continuum within an energy range of 3.5−6 keV to minimize and evaluate systematic uncertainties. Results. The radial profiles of the Fe abundances of relaxed clusters with a cD galaxy at their X-ray peak have similar slopes. These clusters show similar enhancements in the Fe abundance within 0.1r 180 , and at 0.1−0.3r 180 , they have flatter Fe abundance profiles at 0.4 ∼ 0.5 solar, with a small scatter. Most other clusters, including merging clusters, also have similar Fe abundance profiles beyond 0.1r 180 . These clusters may have universal metal enrichment histories, and a significant amount of Fe was synthesized at a very early stage in cluster formation. Mergers of clusters can destroy the central Fe peak.

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Section: Mixing Of the Icm In Non-cd Clusterssupporting

confidence: 92%

“…Leccardi et al (2010) found that some medium-and high-entropy core systems have central abundance excess, most of which are undergoing a phase of rapid dynamical changes, and suggested that these clusters originate from low-entropy core systems.…”

Section: Mixing Of the Icm In Non-cd Clustersmentioning

confidence: 99%

Radial profiles of Fe abundance in the intracluster medium of nearby clusters observed withXMM-Newton

Matsushita

2011

A&A

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“…Leccardi et al 2010;Baldi et al 2012b). The data points are plotted as function as radius and redshift, separating between CC and NCC systems, in Fig.…”

Section: Results On the Spatially Resolved Abundance Evolutionmentioning

confidence: 99%

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

Ettori

Baldi

Balestra

et al. 2015

A&A

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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.

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“…The fraction of CC objects would then be computed from the subsample and not from HIFLUGCS. At variance with the cores, it has been found that in cluster outskirts the surface-brightness profiles are essentially self-similar (Neumann 2005;Croston et al 2008;Leccardi et al 2010), so the selection based on the fluxes in the outer regions should be unbiased. We define a new sample by selecting those objects for which the flux in an annulus excluding the core, and not the total flux, is above a given flux limit.…”

Section: Selection Of the Subsamplementioning

confidence: 99%

The cool-core bias in X-ray galaxy cluster samples

Eckert

Molendi²,

Paltani³

2010

A&A

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215

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Aims. When selecting flux-limited cluster samples, the detection efficiency of X-ray instruments is not the same for centrally-peaked and flat objects, which introduces a bias in flux-limited cluster samples. We quantify this effect in the case of a well-known cluster sample, HIFLUGCS. Methods. We simulate a population of X-ray clusters with various surface-brightness profiles, and use the instrumental characteristics of the ROSAT All-Sky Survey (RASS) to select flux-limited samples similar to the HIFLUGCS sample and predict the expected bias. For comparison, we also estimate observationally the bias in the HIFLUGCS sample using XMM-Newton and ROSAT data. Results. We find that the selection of X-ray cluster samples is significantly biased (∼29%) in favor of the peaked, cool-core (CC) objects, with respect to non-cool-core (NCC) systems. Interestingly, we find that the bias affects the low-mass, nearby objects (groups, poor clusters) much more than the more luminous objects (i.e massive clusters). We also note a moderate increase of the bias for the more distant systems. Conclusions. Observationally, we propose to select the objects according to their flux in a well-defined physical range excluding the cores, 0.2r 500 −r 500 , to get rid of the bias. From the fluxes in this range, we reject 13 clusters out of the 64 in the HIFLUGCS sample, none of which appears to be NCC. As a result, we estimate that less than half (35-37%) of the galaxy clusters in the local Universe are strong CC. In the paradigm where the CC objects trace relaxed clusters as opposed to unrelaxed, merging objects, this implies that to the present day the majority of the objects are not in a relaxed state. From this result, we estimate a rate of heating events of ∼1/3 Gyr −1 per dark-matter halo.

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Thermo-dynamic and chemical properties of the intra-cluster medium

Cited by 55 publications

References 117 publications

Radial profiles of Fe abundance in the intracluster medium of nearby clusters observed withXMM-Newton

Radial profiles of Fe abundance in the intracluster medium of nearby clusters observed withXMM-Newton

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

The cool-core bias in X-ray galaxy cluster samples

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