Related papers: Enhanced Peculiar Velocities in Brane-Induced Grav…
We extend the earlier linear studies of cosmological peculiar velocities to Friedmann universes with nonzero spatial curvature. In the process, we also compare our results with those obtained in cosmologies with Euclidean spatial sections.…
Heavy particles suspended in a turbulent flow settle faster than in a still fluid. This effect stems from a preferential sampling of the regions where the fluid flows downward and is quantified here as a function of the level of turbulence,…
We explore the detectability of bulk motions in the X-ray emitting intracluster medium (ICM) using a catalog of 1,836 mock Astro-E2 observations of simulated clusters of galaxies. We generate high resolution mock spectra for two observing…
We investigate the cosmological properties of an "induced gravity" brane scenario in the absence of mirror symmetry with respect to the brane. We find that brane evolution can proceed along one of four distinct branches. By contrast, when…
We discuss a Brane World scenario where we live on a 3-brane with massive gravity in infinite-volume bulk. The bulk graviton can be much heavier than the inverse Hubble size, as heavy as the bulk Planck scale, whose lower bound is roughly…
We propose an interpretation for the cosmological constant problem based on modeling the universe as a 3-brane embedded in the bulk of 5-dimensional supergravity with hypermultiplets. When solving the modified Friedmann equations the…
Modified gravitational forces in models that seek to explain cosmic acceleration without dark energy typically predict deviations in the abundance of massive dark matter halos. We conduct the first, simulation calibrated, cluster abundance…
Cosmological data from the cosmic microwave background (CMB), baryon acoustic oscillations, and Type Ia supernovae suggest that the component driving the accelerated expansion of the Universe may be dynamical at the $\sim 2.5$-$3\sigma$ CL.…
The gravitational potential of clusters of galaxies acts as a cosmic telescope allowing us to find and study galaxies at fainter limits than otherwise possible and thus probe closer to the epoch of formation of the first galaxies. We use…
3D-Particle Tracking (3D-PTV) and Phase Sensitive Constant Temperature Anemometry in pseudo-turbulence--i.e., flow solely driven by rising bubbles-- were performed to investigate bubble clustering and to obtain the mean bubble rise…
The observed incidence of strongly lensing clusters exceeds the predictions of a Lambda-CDM model by about a factor of 10. We revisit the observational side of this discrepancy by measuring the incidence of strong lensing in a subsample of…
A maximum-likelihood method, tested as an unbiased estimator from numerical simulations, is used to estimate cosmic bulk flow from peculiar velocity surveys. The likelihood function is applied to four observational catalogues (ENEAR, SFI++,…
The recent detection of Doppler shifts of X-ray spectral lines in the intracluster gas of the Centaurus and Perseus clusters of galaxies with ASCA has raised the question of the frequency of such velocity gradients and their relation to…
In the late 1990's, observations of 93 Type Ia supernovae were analysed in the framework of the FLRW cosmology assuming these to be `standard(isable) candles'. It was thus inferred that the Hubble expansion rate is accelerating as if driven…
Recent combined analyses of the CMB and galaxy cluster data reveal unexpectedly large and anisotropic peculiar velocity fields at large scales. We study cosmic models with included vorticity, acceleration and total angular momentum of the…
The Bullet Cluster has provided some of the best evidence for the $\Lambda$ cold dark matter ($\Lambda\rm{CDM}$) model via direct empirical proof of the existence of collisionless dark matter, while posing a serious challenge owing to the…
We address the issue of whether extra dimensions could have an infinite volume and yet reproduce the effects of observable four-dimensional gravity on a brane. There is no normalizable zero-mode graviton in this case, nevertheless correct…
Comparing the observed peculiar velocities of the Local Group and of nearby Abell clusters of galaxies with those predicted using linear perturbation theory and the 3-D reconstruction algorithm of Branchini \& Plionis (1995) the value of…
We explore a new class of braneworld models in which the scalar curvature of the (induced) brane metric contributes to the brane action. The scalar curvature term arises generically on account of one-loop effects induced by matter fields…
The SMAC project is a Fundamental Plane peculiar velocity survey of 56 clusters of galaxies to a depth of cz ~ 12000 km/s. We present here some results from the analysis of the SMAC velocity field, focussing on three specific features: the…