Related papers: Gravitational Lensing by Dark Matter Caustics

Dark Matter (DM) being the vital ingredient in the cosmos, still remains a mystery. Standard assumption is that the collisionless cold dark matter (CCDM) particles are represented by some weakly interacting fundamental fields which can not…

Matter in the universe has become ``dark'' or ``missing'' through misconceptions about the fluid mechanics of gravitational structure formation. Gravitational condensation occurs on non-acoustic density nuclei at the largest Schwarz length…

Caustics are a generic feature of the nonlinear growth of structure in the dark matter distribution. If the dark matter were absolutely cold, its mass density would diverge at caustics, and the integrated annihilation probability would also…

Gravitational collapse of dark matter, merger of dark matter haloes and tidal disruption of satellites are among processes which lead to the formation of fine and dense dark matter shells, also known as dark matter caustics. The putative…

Dark matter is an important ingredient of galaxies, as was recognised early on by Ken Freeman himself! Evidence for dark matter halos is still indirect, based on analysing motions of tracers such as gas and stars. In a sense the visible…

We present theoretical and observational studies of strong gravitational lenses produced by clusters of galaxies. Our purpose is to test the Cold Dark Matter (CDM) model at small and highly non-linear scales where it has been claimed that…

Ordinary baryonic particles (such as protons and neutrons) account for only one-sixth of the total matter in the Universe. The remainder is a mysterious "dark matter" component, which does not interact via the electromagnetic force and thus…

There is good evidence that most of the baryons in the Universe are dark and some evidence that most of the matter in the Universe is nonbaryonic with cold dark matter (cdm) being a promising possibility. We discuss expectations for the…

The detailed distribution of mass within clusters of galaxies can be used to probe the nature of dark matter. We show that constraints on the extent of the mass distribution around galaxies in the rich cluster Abell 2218 obtained from…

In the generic CDM cosmogony, dark-matter halos emerge too lumpy and centrally concentrated to host observed galactic disks. Moreover, disks are predicted to be smaller than those observed. We argue that the resolution of these problems may…

The distribution of the non-luminous matter in galaxies of different luminosity and Hubble type is much more than a proof of the existence of dark particles governing the structures of the Universe. Here, we will review the complex but…

This paper argues that there is a large population of dark galaxies which reveals its presence by the gravitational lensing of quasars, and outnumbers normal galaxies by around 3:1. There are 8 double quasars with a separation greater than…

Unveiling the true nature of Dark Matter (DM), which manifests itself only through gravity, is one of the principal quests in physics. Leading candidates for DM are weakly interacting massive particles (WIMPs) or ultralight bosons (axions),…

It is now, generally, believed that the presence of some form of dark matter is essential to explain the flat rotation curves of galaxies, and anomalous large velocities of galaxies in the clusters and superclusters. This dark matter turns…

According to the current concordance cosmological model, the dark matter (DM) particles are collision-less and produce self-gravitating structures with a central cusp which, generally, is not observed. The observed density tends to a…

The cold dark matter (CDM) cosmological model has been remarkably successful in explaining cosmic structure over an enormous span of redshift, but it has faced persistent challenges from observations that probe the innermost regions of dark…

The current knowledge of cosmological structure formation suggests that Cold Dark Matter (CDM) halos possess a nonspherical density profile, implying that cosmic structures can be potential sources of gravitational waves via power transfer…

We study the problem of gravitational lensing by an isothermal elliptical density galaxy in the presence of a tidal perturbation. When the perturbation is fairly strong and oriented near the galaxy's minor axis, the lens can produce image…

One of the principal discoveries in modern cosmology is that standard model particles (including baryons, leptons and photons) together comprise only 5% of the mass-energy budget of the Universe. The remaining 95% consists of dark energy…

Gravitational lensing studies suggest that the Universe may contain a population of dark galaxies; we investigate this intriguing possibility and propose a mechanism to explain their nature. In this mechanism a dark galaxy is formed with a…