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Theoretical studies of the physical processes in clusters of galaxies are mainly based on the results of numerical simulations, which in turn are often directly compared to X-ray observations. Although trivial in principle, these…

Astrophysics · Physics 2009-11-10 P. Mazzotta , E. Rasia , L. Moscardini , G. Tormen

(Abridged) We revisit the scaling relationships between the dark matter mass and observed X-ray luminosity and temperature of galaxy clusters and groups in the local Universe. Specifically, we compare recent observations with analytic…

The aim of the present work is to show that, contrary to popular belief, galaxy clusters are **not** expected to be self-similar, even when the only energy sources available are gravity and shock-wave heating. In particular, we investigate…

Astrophysics · Physics 2009-11-11 Y. Ascasibar , R. Sevilla , G. Yepes , V. Mueller , S. Gottloeber

In this review, we describe our current understanding of cluster formation: from the general picture of collapse from initial density fluctuations in an expanding Universe to detailed simulations of cluster formation including the effects…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Andrey Kravtsov , Stefano Borgani

Recently, Suzaku has produced temperature and entropy profiles, along with profiles of gas density, gas fraction, and mass, for multiple galaxy clusters out to ~r_200 (~= virial radius). In this paper, we compare these novel X-ray…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Jack O. Burns , Samuel W. Skillman , Brian W. O'Shea

Recent X-ray observations have been used to demonstrate that the cluster gas mass-temperature relation is steeper than theoretical self-similar predictions drawn from numerical simulations that consider the evolution of the cluster gas…

Astrophysics · Physics 2009-11-07 Ian G. McCarthy , Arif Babul , Michael L. Balogh

Studies of the X-ray surface brightness profiles of clusters, coupled with theoretical considerations, suggest that the breaking of self-similarity in the hot gas results from an `entropy floor', established by some heating process, which…

Astrophysics · Physics 2009-10-31 E. J. Lloyd-Davies , T. J. Ponman , D. B. Cannon

Evolution of the cluster temperature function is extremely sensitive to the mean matter density of the universe. Current measurements based on cluster temperature surveys indicate that Omega_M ~ 0.3 with a 1-sigma statistical error ~0.1,…

Astrophysics · Physics 2009-10-31 G. M. Voit

Pronounced core-halo patterns of dark matter and gas density profiles, observed in relaxed galaxies and clusters, were hitherto fitted by empirical power-laws. On the other hand, similar features are well known from astrophysical plasma…

Astrophysics · Physics 2009-11-11 M. P. Leubner

We present a simple model to describe the dark matter density, the gas density, and the gas temperature profiles of galaxy clusters. Analytical expressions for these quantities are given in terms of only five free parameters with a clear…

Astrophysics · Physics 2009-11-13 Y. Ascasibar , J. M. Diego

The thermodynamics of the diffuse, X-ray emitting gas in clusters of galaxies is linked to the entropy level of the intra cluster medium. In particular, models that successfully reproduce the properties of local X-ray clusters and groups…

Astrophysics · Physics 2009-10-31 Paolo Tozzi , Caleb Scharf , Colin Norman

We calibrate the galaxy cluster mass - temperature relation using the temperature profiles of intracluster gas observed with ASCA (for hot clusters) and ROSAT (for cool groups). Our sample consists of apparently relaxed clusters for which…

Astrophysics · Physics 2009-10-31 J. Nevalainen , M. Markevitch , W. R. Forman

The physics of the intracluster medium, in particular the values for the thermal conductivity and the viscosity are largely unknown and subject to an ongoing debate. Here, we study the effect of viscosity on the thermal state of the…

Astrophysics · Physics 2007-05-23 M. Brüggen , M. Ruszkowski

(Abridged) This is the second in a series of papers in which we derive simultaneous constraints on cosmology and X-ray scaling relations using observations of massive, X-ray flux-selected galaxy clusters. The data set consists of 238…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Adam Mantz , Steven W. Allen , Harald Ebeling , David Rapetti , Alex Drlica-Wagner

We use the galaxy cluster X-ray temperature distribution function to constrain the amplitude of the power spectrum of density inhomogeneities on the scale corresponding to clusters. We carry out the analysis for critical density universes,…

Astrophysics · Physics 2015-06-24 Pedro T P Viana , Andrew R Liddle

Observations of the evolution of the galaxy cluster X-ray luminosity function suggest that the entropy of the intra-cluster medium plays a significant role in determining the development of cluster X-ray properties. I present a theoretical…

Astrophysics · Physics 2015-06-24 Richard G Bower

We present a set of gas-dynamical simulations of galaxy groups and clusters aimed at exploring the effect of non-gravitational heating. We use GASOLINE, a parallel Tree+SPH code, to simulate the formation of four cosmic halos with…

Astrophysics · Physics 2008-11-26 S. Borgani , F. Governato , J. Wadsley , N. Menci , P. Tozzi , T. Quinn , J. Stadel , G. Lake

We present accurate mass and thermodynamic profiles for a sample of 56 galaxy clusters observed with the Chandra X-ray Observatory. We investigate the effects of local gravitational acceleration in central cluster galaxies, and we explore…

I review some important aspects of the structural and statistical properties of the nearby X-ray galaxy cluster population, discussing the new constraints on mass profiles, the mass-temperature relation, and the entropy of the intracluster…

Astrophysics · Physics 2007-05-23 G. W. Pratt

We discuss the energy density,temperature and entropy of dark matter (DM) and dark energy (DE) as functions of the scale factor $a$ in an expanding universe. In a model of non-interacting dark components we repeat a derivation from…

General Relativity and Quantum Cosmology · Physics 2017-03-27 Z. Haba