相关论文: Revisiting the Cosmic Cooling Crisis
The cold ($\sim 10^{4}\,{\rm K}$) component of the circumgalactic medium (CGM) accounts for a significant fraction of all galactic baryons. However, using current galaxy-scale simulations to determine the origin and evolution of cold CGM…
Baryonic effects such as AGN feedback can significantly impact the matter clustering, are harder to model from first principles, and emerge as a severe limiting factor in weak lensing cosmology. To tackle this issue, we propose a generic…
There is compelling evidence that black holes (BHs) in cluster centers vigorously interact with their surroundings, indicating that any realistic model of cluster formation needs to account for these processes. Here we use high-resolution…
We present results of including heating and cooling in cosmological simulations of the $\Lambda$CDM cosmology and demonstrate their effects on scaling laws of galaxy clusters. The scaling relations when radiative cooling is included are in…
The recent observational evidence for the current cosmic acceleration have stimulated renewed interest in alternative cosmologies, such as scenarios with interaction in the dark sector (dark matter and dark energy). In general, such models…
In the centers of many galaxy clusters, the hot ($\sim$10$^7$ K) intracluster medium (ICM) can become dense enough that it should cool on short timescales. However, the low measured star formation rates in massive central galaxies and…
Recent BOOMERANG and MAXIMA-I analyses of the angular power spectrum of the Cosmic Microwave Background put more stringent constraints on the cosmological parameters. I show that these constraints are consistent with the observed baryon…
Thanks to new technology of observations and fresh inputs from particle physics, cosmology has advanced on both observational and theoretical fronts. It is therefore opportune that we take stock of the cosmological situation today and…
We consider the possibility that the dark matter in the halos of galaxies may be in the form of clusters of \macho s within which are embedded cold, dense gas clouds. Microlensing experiments have found evidence that the Galactic halo…
We compute, including a current state-of-the-art treatment of hydrodynamical processes, heating and cooling, a variety of cosmological models into the extreme nonlinear phase to enable comparisons with observations. First, we note the…
We study the evolution of two fundamental properties of galaxy clusters: the luminosity function (LF) and the scaling relations between the total galaxy number N (or luminosity) and cluster mass M. Using a sample of 27 clusters (0<z<0.9)…
The combination of multiple observational probes has long been advocated as a powerful technique to constrain cosmological parameters, in particular dark energy. The Dark Energy Survey has measured 207 spectroscopically--confirmed Type Ia…
We derive constraints on the mass-temperature relation of galaxy clusters from their observed luminosity-temperature relation and X-ray temperature function. Adopting the isothermal gas in hydrostatic equilibrium embedded in the universal…
The angular power spectrum and polarization of the cosmic microwave background radiation (CMB), the relative abundances of primordial hydrogen, deuterium and helium isotopes, and the large-scale structure of the universe all indicate that…
Using Chandra data for a sample of 26 galaxy groups, we constrained the central cooling times (CCTs) of the ICM and classified the groups as strong cool-core (SCC), weak cool-core (WCC) and non-cool-core (NCC) based on their CCTs. The total…
We present the analysis of baryonic and non-baryonic matter distribution in a sample of ten nearby clusters (0.03<z<0.09) with temperatures between 4.7 and 9.4 keV. These galaxy clusters are studied in detail using X-ray data and global…
In the local universe, a large fraction of the baryon content is believed to exist as diffuse gas in filaments. While this gas is directly observable in X-ray emission around clusters of galaxies, it is primarily studied through its UV…
The masses of clusters of galaxies estimated by gravitational lensing exceed in many cases the mass estimates based on hydrostatic equilibrium. This may suggest the existence of nonthermal pressure. We ask if radio galaxies can heat and…
Numerical simulations with varying realism indicate an emergent principle -- multiphase condensation and large cavity power occur when the ratio of the cooling time to the free-fall time ($t_{\rm cool}/t_{\rm ff}$) falls below a threshold…
The properties of nearby galaxy clusters limit the range of cosmological parameters consistent with our universe. We describe the limits which arise from studies of the intracluster medium (ICM) mass fraction fICM and consideration of the…