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Surveys of galaxy clusters provide a promising method of testing models of structure formation in the universe. Within the context of our standard structure formation scenario, surveys provide measurements of the geometry of the universe…

Astrophysics · Physics 2007-05-23 Joseph J. Mohr

We predict the biasing and clustering properties of galaxy clusters that are expected to be observed in the catalogues produced by two forthcoming X-ray and Sunyaev-Zel'dovich effect surveys. We study a set of flat cosmological models where…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-02 C. Fedeli , L. Moscardini , S. Matarrese

The correlation function of galaxy clusters has often been used as a test of cosmological models. A number of assumptions are implicit in the comparison of theoretical expectations to data. Here we use an ensemble of ten large N-body…

Astrophysics · Physics 2015-06-24 Vincent R. Eke , Shaun Cole , Carlos S. Frenk , Julio F. Navarro

We quantify the morphologies and dynamical states of 59 galaxy clusters using the power-ratio technique of Buote & Tsai applied to ROSAT PSPC X-ray images. The clusters exhibit a particularly strong $P_2/P_0 - P_4/P_0$ correlation in the…

Astrophysics · Physics 2009-10-28 David A. Buote , John C. Tsai

We present an analysis of the 2-point correlation function, of the X-ray Brightest Abell-type Cluster sample (XBACs; Ebeling et al. 1998) and of the cosmological constraints that it provides. If \xi(r) is modelled as a power-law, we find…

Astrophysics · Physics 2009-10-31 S. Borgani , M. Plionis , E. Kolokotronis

Galaxy morphologies and star-formation rates depend on environment. Galaxies in under-dense regions are generally star-forming and disky whereas galaxies in overdense regions tend to be early-type and not actively forming stars. The…

Astrophysics of Galaxies · Physics 2015-11-04 Ian D. Roberts , Laura C. Parker , Ananthan Karunakaran

Using the simulation of Katz & White we have tested the viability of X-ray analysis for constraining the intrinsic shapes of clusters of galaxies considering the effects of both substructure and steep temperature gradients. We restrict…

Astrophysics · Physics 2009-10-22 D. A. Buote , J. C. Tsai

Precise determination of galaxy cluster masses is crucial for establishing reliable mass-observable scaling relations in cluster cosmology. We employ graph neural networks (GNNs) to estimate galaxy cluster masses from radially sampled…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-14 Asif Iqbal , Subhabrata Majumdar , Elena Rasia , Gabriel W. Pratt , Daniel de Andres , Jean-Baptiste Melin , Weiguang Cui

Cosmological simulations are fundamental tools to study structure formation and the astrophysics of evolving structures, in particular clusters of galaxies. While hydrodynamical simulations cannot sample efficiently large volumes and…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-01 Fabio Zandanel , Mattia Fornasa , Francisco Prada , Thomas H. Reiprich , Florian Pacaud , Anatoly Klypin

Evolution of the cluster population has been recognized as a powerful cosmological tool. While the present--day abundance of X-ray clusters is degenerate in $\sigma_8$, $n$ and $\Omega_0$, Oukbir and Blanchard (1992, 1997) have pointed out…

Astrophysics · Physics 2007-05-23 A. Blanchard , J. G. Bartlett

This talk reviews the scientific motivations, the potential difficulty and recent advances in cosmology using cluster number-counts in the X-ray band. Our forward modelling approach shows that many of the practical and conceptual…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-12 Marguerite Pierre

The exploitation of clusters of galaxies as cosmological probes relies on accurate measurements of their total gravitating mass. X-ray observations provide a powerful means of probing the total mass distribution in galaxy clusters, but…

Astrophysics · Physics 2009-11-13 Rocco Piffaretti , Riccardo Valdarnini

We investigate the cosmological implications of studying galaxy clustering using a tomographic approach applied to the final BOSS DR12 galaxy sample, including both auto- and cross-correlation functions between redshift shells. We model the…

We present a deep UBI CCD survey using the Palomar 5-m telescope of a sample of high X-ray luminosity, distant clusters selected from the ROSAT All-Sky Survey. The 10 clusters lie at z=0.22-0.28, an era where evolutionary effects have been…

Astrophysics · Physics 2009-10-30 Ian Smail , Alastair C. Edge , Richard S. Ellis , Roger D. Blandford

Comparisons between observed and predicted strong lensing properties of galaxy clusters have been routinely used to claim either tension or consistency with $\Lambda$CDM cosmology. However, standard approaches to such cosmological tests are…

We explore the use of strong lensing by galaxy clusters to constrain the dark energy equation of state and its possible time variation. The cores of massive clusters often contain several multiply imaged systems of background galaxies at…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Anson D'Aloisio , Priyamvada Natarajan

As the largest gravitationally bound structures known, clusters provide clear constraints on the formation of structure and on the composition of the universe. Despite their extreme importance for cosmology the number of clusters at high…

Astrophysics · Physics 2007-05-23 I. M. Gioia

The X-ray emission from a simulated massive stellar cluster is investigated. The emission is calculated from a 3D hydrodynamical model which incorporates the mechanical feedback from the stellar winds of 3 O-stars embedded in a giant…

Solar and Stellar Astrophysics · Physics 2015-06-19 H. Rogers , J. M. Pittard

In galaxy clusters, the relations between observables in X-ray and millimeter wave bands and the total mass have normalizations, slopes and redshift evolutions that are simple to estimate in a self-similar scenario. We study these scaling…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 S. Ettori

Context: We present the first Cosmological Parameter inferences from eROSITA X-ray observations of galaxy clusters using a Machine Learning algorithm. Methods: We train a Random Forest using mock catalogs of clusters from Magneticum…

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