Lorenzo Lovisari

X-Ray Morphological Analysis of the Planck ESZ Clusters

X-ray observations show that galaxy clusters have a very large range of morphologies. The most disturbed systems which are good to study how clusters form and grow and to test physical models, may potentially complicate cosmological studies because the cluster mass determination becomes more challenging. Thus, we need to understand the cluster properties of our samples to reduce possible biases. This is complicated by the fact that different experiments may detect different cluster populations. For example, SZ selected cluster samples have been found to include a greater fraction of disturbed systems than X-ray selected samples. In this paper we determined eight morphological parameters for the Planck Early Sunyaev-Zeldovich (ESZ) objects observed with XMM-Newton. We found that two parameters, concentration and centroid-shift, are the best to distinguish between relaxed and disturbed systems. For each parameter we provide the values that allow one to select the most relaxed or most disturbed objects from a sample. We found that there is no mass dependence on the cluster dynamical state. By comparing our results with what was obtained with REXCESS clusters, we also confirm that indeed the ESZ clusters tend to be more disturbed, as found by previous studies.

X-ray analysis of the galaxy group UGC 03957 beyond R200 with Suzaku

Context. In the last few years, the outskirts of galaxy clusters have been studied in detail and the analyses have brought up interesting results such as indications of possible gas clumping and the breakdown of hydrostatic, thermal, and ionization equilibrium. These phenomena affect the entropy profiles of clusters, which often show deviations from the self-similar prediction around R 200 . However, significant uncertainties remain for groups of galaxies. In particular the question, of whether entropy profiles are similar to those of galaxy clusters. Aims. We investigated the gas properties of the galaxy group UGC 03957 up to 1.4 R 200 ≈ 1.4 Mpc in four azimuthal directions with the Suzaku satellite. We checked for azimuthal symmetry and obtained temperature, entropy, density, and gas mass profiles. Previous studies point to deviations from equilibrium states at the outskirts of groups and clusters and so we studied the hydrodynamical status of the gas at these large radii. Methods. We performed a spectral analysis of five Suzaku observations of UGC 03957 with ~138 ks good exposure time in total and five Chandra snapshot observations for point source detection. We investigated systematic effects such as point spread function and uncertainties in the different background components, and performed a deprojection of the density and temperature profile. Results. We found a temperature drop of a factor of ~3 from the center to the outskirts that is consistent with previous results for galaxy clusters. The metal abundance profile shows a flat behavior towards large radii, which is a hint for galactic winds as the primary ICM enrichment process. The entropy profile is consistent with numerical simulations after applying a gas mass fraction correction. Feedback processes and AGN activity might be one explanation for entropy modification, imprinting out to larger radii in galaxy groups than in galaxy clusters. Previous analyses for clusters and groups often showed an entropy flattening or even a drop around ~ R 200 , which can be an indication of clumping or non-equilibrium states in the outskirts. Such entropy behavior is absent in UGC 03957. The gas mass fraction is well below the cosmic mean but rises above this value beyond R 200 , which could be a hint for deviations from hydrostatic equilibrium at these large radii. By measuring the abundance of the α -elements Si and S at intermediate radii we determined the relative number of different supernovae types and found that the abundance pattern can be described by a relative contribution of 80%−100% of core-collapse supernovae. This result is in agreement with previous measurements for galaxy groups.

Correlation between the Total Gravitating Mass of Groups and Clusters and the Supermassive Black Hole Mass of Brightest Galaxies

Supermassive black holes (BHs) residing in the brightest cluster galaxies are over-massive relative to the stellar bulge mass or central stellar velocity dispersion of their host galaxies. As BHs residing at the bottom of the galaxy clusters potential well may undergo physical processes that are driven by the large-scale characteristics of the galaxy clusters, it is possible that the growth of these BHs is (indirectly) governed by the properties of their host clusters. In this work, we explore the connection between the mass of BHs residing in the brightest group/cluster galaxies (BGGs/BCGs) and the virial temperature, and hence total gravitating mass, of galaxy groups/clusters. To this end, we investigate a sample of 17 BGGs/BCGs with dynamical BH mass measurements and utilize XMM-Newton X-ray observations to measure the virial temperatures and infer the

RELICS: Strong Lens Models for Five Galaxy Clusters from the Reionization Lensing Cluster Survey

M_{\rm 500}

CHEERS: The chemical evolution RGS sample

mass of the galaxy groups/clusters. We find that the

Metal distribution in the intracluster medium: a comprehensive numerical study of twelve galaxy clusters

M_{\rm BH} - kT

RELICS: Strong Lensing Analysis of the Galaxy Clusters Abell S295, Abell 697, MACS J0025.4-1222, and MACS J0159.8-0849

relation is significantly tighter and exhibits smaller scatter than the

The Double Galaxy Cluster A2465. III. X-Ray and Weak-lensing Observations

M_{\rm BH} - M_{\rm bulge}

RELICS: Strong-lensing analysis of the massive clusters MACS J0308.9+2645 and PLCK G171.9-40.7

relations. The best-fitting power-law relations are

XMM-Newton X-ray and HST weak gravitational lensing study of the extremely X-ray luminous galaxy cluster Cl J120958.9+495352 (z = 0.902)

\log_{10} (M_{\rm BH}/10^{9} \ \rm{M_{\odot}}) = 0.20 + 1.74 \log_{10} (kT/1 \ \rm{keV})