Related papers: Revisiting the Cosmic Cooling Crisis
We study the properties of X-ray galaxy clusters in four cold dark matter models with different baryon fraction $\Omega_{BM}$ ranging from 5 to 20 per cent. By using an original three-dimensional hydrodynamic code based on the piecewise…
We study the baryon mass fraction in a set of hydrodynamical simulations of galaxy clusters performed using the Tree+SPH code GADGET-2. We investigate the dependence of the baryon fraction upon the radiative cooling, star formation,…
(Abriged) We present the analysis of the baryonic content of 52 X-ray luminous galaxy clusters observed with Chandra in the redshift range 0.3-1.273. We use the deprojected X-ray surface brightness profiles and the measured values of the…
The universal baryonic mass fraction (Omega_b/Omega_m) can be sensitively constrained using X-ray observations of galaxy clusters. In this paper, we compare the baryonic mass fraction inferred from measurements of the cosmic microwave…
The Millennium Gas project aims to undertake smoothed-particle hydrodynamic resimulations of the Millennium Simulation, providing many hundred massive galaxy clusters for comparison with X-ray surveys (170 clusters with kTsl > 3 keV). This…
We investigate phenomenological models of star formation and supernova feedback in N-body/SPH simulations of galaxy formation. First, we compare different prescriptions in the literature for turning cold gas into stars neglecting feedback…
Baryon fraction in clusters, combined with constraints from primordial nucleosynthesis is currently used to provide a robust upper limit on the cosmological density parameter $\Omega_0$. Current analyses lead to gas fractions at virial…
I re-examine the relation between virial mass and concentration for groups and clusters of galaxies as measured in a number of recent works. As previously noted by several authors, low-mass clusters and groups of galaxies display…
We discuss an extended set of Tree+SPH simulations of galaxy clusters, with the goal of investigating the interplay between numerical resolution effects and star-formation/feedback processes. The simulated clusters span the mass range…
Clusters of galaxies are thought to contain about ten times as much dark matter as baryonic matter. The dark component therefore dominates the gravitational potential of the cluster, and the baryons confined by this potential radiate X-rays…
I report the current status on the determinations of the baryon fractions and dynamical/lensing masses of galaxy clusters as well as the $\sigma$ - $T$ relationship, making use of all the published data in literature which include 304…
The observed baryon fraction and velocity--temperature relation in clusters of galaxies are compared with hydrodynamic simulations in two cosmological models : standard (Omega = 1) and a low-density flat (Omega=0.45 and \lambda=0.55) CDM…
The baryon fraction in galaxy clusters is one of the most direct way to constrain $\omo$. The baryonic fraction is estimated to be in the range fb = (0.15 - 0 .20) h^{-3/2} which is several times higher than expected from the observed light…
We explore the near-infrared properties of galaxies within 27 galaxy clusters using data from the Two Micron All Sky Survey (2MASS). For a subsample of 13 clusters with available X-ray imaging data, we examine both the properties of the…
We show that the high local baryonic fraction, M(bar) ~ 1/3 M(tot), found in groups and clusters of galaxies does not reconcile the observed cosmological baryon density with the standard Big-Bang prediction. Taking into account recent…
Observations of clusters of galaxies suggest that they contain significantly fewer baryons (gas plus stars) than the cosmic baryon fraction. This `missing baryon' puzzle is especially surprising for the most massive clusters which are…
We review recent progress in the description of the formation and evolution of galaxy clusters in a cosmological context by using numerical simulations. We focus our presentation on the comparison between simulated and observed X-ray…
Several recent studies used the hot gas fraction of galaxy clusters as a standard ruler to constrain dark energy, which provides competitive results compared to other techniques. This method, however, relies on the assumption that the…
Galaxy groups are the least massive systems where the bulk of baryons begin to be accounted for. Not simply the scaled-down versions of rich clusters following self-similar relations, galaxy groups are ideal systems to study baryon physics,…
We propose a new cosmological test of gravity, by using the observed mass fraction of X-ray emitting gas in massive galaxy clusters. The cluster gas fraction, believed to be a fair sample of the average baryon fraction in the Universe, is a…