相关论文: Testing Omega0 with X-ray Clusters: a Physical App…
We present a method from an X-ray observation of a galaxy cluster to measure the radial profile of the dark matter velocity dispersion, sigma_DM, and to compare the dark matter ``temperature'' defined as mu m_p sigma_DM**2 / k_B with the…
Recently, some very strong correlations between the distribution of dark matter and baryons (the dark matter-baryon relations) in galaxies with very different morphologies, masses, sizes, and gas fractions have been obtained. Some models…
We analysed XMM-{\it Newton} EPIC data for 53 galaxy clusters. Through 2D spectral maps, we provide the most detailed and extended view of the spatial distribution of temperature (kT), pressure (P), entropy (S) and metallicity (Z) of galaxy…
The rotation velocity profiles of galaxies (rotation curves) remain unexpectedly flat at large distances, where visible matter alone should make the rotation velocity decrease with radius. Conventionally, this requires a large amount of…
We present the study of three bright Early-Type galaxies hosted in groups or poor clusters: NGC 1399, NGC 1404 and NGC 507. We used ROSAT HRI, PSPC and, when available, higher resolution Chandra data to study the structure of the X-ray…
To distinguish between the different theories proposed to explain massive star formation, it is crucial to establish the distribution, the extinction, and the density of low-mass stars in massive star-forming regions. We analyze deep X-ray…
Studies of the diffuse X-ray emitting gas in galaxy clusters have provided powerful constraints on cosmological parameters and insights into plasma astrophysics. However, measurements of the faint cluster outskirts have become possible only…
The observed evolution of the galaxy cluster X-ray integral temperature distribution function between $z=0.05$ and $z=0.32$ is used in an attempt to constrain the value of the density parameter, $\Omega_{0}$, for both open and…
Recent results have suggested that the density of baryons in the Universe, OmegaB, is much more uncertain than previously thought, and may be significantly higher. We demonstrate that a higher OmegaB increases the viability of…
We introduce a new technique for following the formation and evolution of galaxies in cosmological N-body simulations. Dissipationless simulations are used to track the formation and merging of dark matter halos as a function of redshift.…
[Abridged] Since 1971 observations in X rays of thousands galaxy clusters have uncovered huge amounts of hot baryons filling up the deep gravitational potential wells provided by dark matter (DM) halos with sizes of millions light-years and…
Many approaches to obtaining cosmological constraints rely on the connection between galaxies and dark matter. However, the distribution of galaxies is dependent on their formation and evolution as well as the cosmological model, and galaxy…
We summarize a series of papers reporting studies of the ellipticities of X-ray images of five Abell clusters and two early type galaxies to learn about the shape of the gravitational potential and the underlying matter distributions. For…
We present precise measurements of the X-ray gas mass fraction for a sample of luminous, relatively relaxed clusters of galaxies observed with the Chandra Observatory, for which independent confirmation of the mass results is available from…
We review recent advancements in cosmology with galaxy clusters. Galaxy clusters are the most massive objects in the Universe. Consequently the cluster number density as a function of cluster mass, or cluster abundance, is sensitive to…
We present a self consistent method to perfom a joint analysis of Sunyaev-Zel'dovich and weak gravitational lensing observation of galaxy clusters. The spatial distribution of the cluster main constituents is described by a perturbative…
The distribution of offsets between the brightest cluster galaxies of galaxy clusters and the centroid of their dark matter distributions is a promising probe of the underlying dark matter physics. In particular, since this distribution is…
Determining the fundamental properties of the dark matter is one of the most important open problems in particle physics today. If the dark matter particle has spin zero, one of these properties is its CP nature. That is, whether it is…
A major fraction of the mass content of the universe is composed of dark matter (DM), i.e. particles not interacting significantly with electromagnetic radiation, with ordinary matter or self-interacting (cold dark matter). The axion is…
We have used a combination of high resolution cosmological N-body simulations and semi-analytic modelling of galaxy formation to investigate the processes that determine the spatial distribution of galaxies in cold dark matter (CDM) models.…