Related papers: A Dynamically Driven, Universal Thermal Profile of…
We discuss hydrostatic models of galaxy clusters in which heat diffusion balances radiative cooling. We consider two different sources of diffusion, thermal conduction and turbulent mixing, parameterized by dimensionless coefficients, f and…
The temperature and density of the hot diffuse medium pervading galaxy groups and clusters combine into one significant quantity, the entropy. Here we express the entropy levels and profiles in model-independent forms by joining two…
X-ray observations of hot gas in galaxy groups indicate higher entropies than can be achieved in the accretion shocks as it fell into the dark halos. It has been proposed that this entropy excess results from some universal external heating…
Recent X-ray observations have revealed a universal temperature profile of the intracluster gas of non-cooling flow clusters which is flat for r \le 0.2 r_{180}. Numerical simulations, however, obtain a steeper temperature profile in the…
We have performed a series of N-body/hydrodynamical (TreeSPH) simulations of clusters and groups of galaxies, selected from cosmological N-body simulations within a $\Lambda$CDM framework: these objects have been re-simulated at higher…
We examine profiles and scaling properties of the entropy of the intergalactic gas in a sample of 66 virialized systems, ranging in mass from single elliptical galaxies to rich clusters, for which we have resolved X-ray temperature…
The density profile of a cool core of intracluster gas is investigated for a cluster of galaxies that is initially in the virial equilibrium state, and then undergoes radiative cooling. The initial gas profile is derived under the…
Dynamical parameters like average velocity dispersion and temperature profile of galaxy clusters are determined using a quasi equilibrium thermodynamic theory. The calculated velocity dispersion results from theory and simulations shows a…
Using deep photometric data from WFC@INT and [email protected] we measure the outer number density profiles of 19 stellar clusters located in the inner region of the Milky Way halo (within a Galactocentric distance range of 10-30 kpc) in order to…
Cosmological N--body simulations have revealed a remarkable similarity in the structure of dark matter halos formed in hierarchically clustering universes. Regardless of halo mass, cosmological parameters, and power spectrum of initial…
Using the standard dynamical theory of spherical systems, we calculate the properties of spherical galaxies and clusters whose density profiles obey the universal form first obtained in high resolution cosmological N-body simulations by…
We carry out a comparison between observations and hydrodynamic simulations of entropy profiles of groups and clusters of galaxies. We use the Tree+SPH GADGET code to simulate four halos of sizes in the M_500 = 1.0 - 16.e13 h^-1 Msun range,…
The relaxed motion of stars and gas in galactic discs is well approximated by a rotational velocity that is a function of radial position only, implying that individual components have lost any information about their prior states.…
We present first results on the cooling properties derived from Chandra X-ray observations of 83 high-redshift (0.3 < z < 1.2) massive galaxy clusters selected by their Sunyaev-Zel'dovich signature in the South Pole Telescope data. We…
We present hydrodynamical N-body simulations of clusters of galaxies with feedback taken from semi-analytic models of galaxy formation. The advantage of this technique is that the source of feedback in our simulations is a population of…
We present an analysis of 20 galaxy clusters observed with the Chandra X-ray satellite, focussing on the temperature structure of the intracluster medium and the cooling time of the gas. Our sample is drawn from a flux-limited catalogue but…
We propose that turbulent heating, wave pressure and gas exchanges between different regions of disks play a dominant role in determining the preferred, quasi-equilibrium, self-similar states of gas disks on large-scales. We present simple…
On the basis of the universal gas fraction in clusters of galaxies, we estimate that the effective thermal conductivity required to balance radiative cooling in the cores, where the gas temperature is 3-10keV, is about one tenth of the…
The relationship between the X-ray determined temperature $T$ of the intracluster gas and the optical measured velocity dispersion $\sigma$ of the cluster galaxies is often believed to be not only a straightforward but also robust test for…
We present results from a new set of 30 cosmological simulations of galaxy clusters, including the effects of radiative cooling, star formation, supernova feedback, black hole growth and AGN feedback. We first demonstrate that our AGN model…