相关论文: Local Void vs Dark Energy: Confrontation with WMAP…

The recent observations support that our universe is flat and expanding with acceleration. A quintessence model with a general relation between the quintessence potential and the quintessence kinetic energy was proposed to explain the…

We compute the Bayesian evidences for one- and two-parameter models of evolving dark energy, and compare them to the evidence for a cosmological constant, using current data from Type Ia supernova, baryon acoustic oscillations, and the…

We investigate the clustering of dark energy within matter overdensities and voids. In particular, we derive an analytical expression for the dark energy density perturbations, which is valid both in the linear, quasi-linear and fully…

We investigate the possibility of a dark energy component that is scaling with epochs. A phenomenological model is introduced whose energy density depends on the redshift in such a way that a smooth transition among the three dominant…

We place observational constraints on a coupling between dark energy and dark matter by using 71 Type Ia supernovae (SNe Ia) from the first year of the five-year Supernova Legacy Survey (SNLS), the cosmic microwave background (CMB) shift…

We present a simple mechanism which can mimic dark energy with an equation of state w < -1 as deduced from the supernova data. We imagine that the universe is accelerating under the control of a quintessence field, which is moving up a very…

We have studied constraints on the equation of state, $w$, and speed of sound, c_s, of the dark energy from a joint analysis of data from the cosmic microwave background, large scale structure and type-Ia supernovae. We find that current…

Recently there have been suggestions that the Type Ia supernova data can be explained using only general relativity and cold dark matter with no dark energy. In "Swiss cheese" models of the Universe, the standard Friedmann-Robertson-Walker…

Using recent precision measurements of cosmological paramters, we re-examine whether these observations alone, independent of type Ia supernova surveys, are sufficient to imply the existence of dark energy. We find that best measurements of…

The formation of large voids in the Cosmic Web from the initial adiabatic cosmological perturbations of space-time metric, density and velocity of matter is investigated in cosmological model with the dynamical dark energy accelerating…

The possibility that we live in a special place in the universe, close to the center of a large, radially inhomogeneous void, has attracted attention recently as an alternative to dark energy or modified gravity to explain the accelerating…

Two new one-parameter tracking behavior dark energy representations $\omega=\omega_0/(1+z)$ and $\omega=\omega_0 e^{z/(1+z)}/(1+z)$ are used to probe the geometry of the Universe and the property of dark energy. The combined type Ia…

The anomaly in the Cosmic Microwave Background known as the "Cold Spot" could be due to the existence of an anomalously large spherical (few hundreds Mpc/h radius) underdense region, called a "Void" for short. Such a structure would have an…

Hints of a dynamical dark-energy equation of state have appeared in several combined cosmological probes. However, such indications may instead arise from the intrinsic likelihood geometry of individual datasets, residual inter-probe…

The distance duality relation (DDR) between luminosity and angular diameter distances holds if gravity is described by a metric theory and the universe is transparent. Recent cosmological inferences using Type Ia supernovae (SNe~Ia), baryon…

The satellite experiment WMAP has produced for the first time a high-coverage, high resolution survey of the microwave sky, releasing publicly available data that are likely to remain unrivalled for years to come. Here we compare the WMAP…

We find that if we live at the center of an inhomogeneity with total density contrast of roughly 0.1, dark energy is not a cosmological constant at 95% confidence level. Observational constraints on the equation of state of dark energy, w,…

(Abridged) The WMAP 5-year data strongly limit deviations from the minimal LCDM model. We constrain the physics of inflation via Gaussianity, adiabaticity, the power spectrum shape, gravitational waves, and spatial curvature. We also…

Observations reveal a `bulk flow' in the local Universe which is faster and extends to much larger scales than is expected around a typical observer in the standard $\Lambda$CDM cosmology. This is expected to result in a scale-dependent…

Recently Perlmutter et al. suggested a positive value of Einstein's cosmological constant Lambda on the basis of luminosity distances from type-Ia supernovae. However, Lambda world models had earlier been proposed by Hoell & Priester and…