Related papers: Dark matter in $R+R^2$ cosmology
The observational evidence for dark matter on progressively larger cosmic scales is reviewed in a rather pedagogical fashion. Although the emphasis is on dark matter in galaxies and in clusters of galaxies, its cosmological evidence as well…
The physical nature of most of the gravitating mass in the universe is completely mysterious. The astrophysical evidence for the presence of this dark matter and astrophysical constraints on its properties will be reviewed. The most popular…
Many independent high resolution simulations have indicated that the standard collisionless cold dark matter model does not reproduce the structure of observed present day galaxies well. Several possible solutions in the form of…
Progress in observational cosmology over the past five years has established that the Universe is dominated dynamically by dark matter and dark energy. Both these new and apparently independent forms of matter-energy have properties that…
The Large Volume Scenario for getting a non-supersymmetric vacuum in type IIB string theory leads, through the Weyl anomaly and renormalization group running, to an interesting phenomenology. However, for gravitino masses below 500 TeV…
Dark matter could have an electroweak origin, yet communicate with the visible sector exclusively through gravitational interactions. In a set-up addressing the hierarchy problem, we propose a new dark matter scenario where gravitational…
How much dark matter is there in the universe and where is it located? These are two of the most fundamental questions in cosmology. We use in this paper optical and x-ray mass determinations of galaxies, groups, and clusters of galaxies to…
It seems necessary to suppress, at least partially, the formation of structure on subgalactic scales. As an alternative to warm or collisional dark matter, I postulate a condensate of massive bosons interacting via a repulsive interparticle…
Till today, the nature of Dark Matter (DM) remains elusive despite all our efforts. This missing matter of the universe has not been observed by the already operating DM direct-detection experiments, but we can infer its gravitational…
A fine balance between dark and baryonic mass is observed in spiral galaxies. As the contribution of the baryons to the total rotation velocity increases, the contribution of the dark matter decreases by a compensating amount. This poses a…
All presently known stellar-dynamical constraints on the size and mass of the supermassive compact dark object at the Galactic center are consistent with a ball of self-gravitating, nearly non-interacting, degenerate fermions with mass…
Massive gravity previously constructed as the spin-2 quantum gauge theory leads in the mass zero limit to a modification of general relativity. As a relic from the massive theory a vector field v survives which couples to the metric only.…
The dark atoms $XHe$ are the composite Thomson like atomic dark matter candidates. We address two cosmological problems of this model. The excess of new superheavy particles with even negative charge $X^{-2n}$ over the corresponding…
The Universe evolution during the radiation-dominated epoch in the R^2-extended gravity theory is considered. The equations of motion for R and H are solved analytically and numerically. The particle production rate by the oscillating…
Astrophysics gives evidence for the existence of Dark Matter and puts constraints on its nature. The Cold Dark Matter model has become "standard" cosmology combined with a cosmological constant. There are indications that "Cold" Dark Matter…
We consider two problems that have vexed physicists for several decades -- dark matter and the cosmological constant. The problem has been that the former has not been detected while the latter gives a far higher value than detected by…
Light dark matter is a compelling experimental target in light of stringent constraints on heavier WIMPs. However, for a sub-MeV WIMP, the universe is sufficiently well understood at temperatures below 10 MeV that there is no room for it to…
Cold dark matter simulations appear to disagree with the observations on small distance scales. Here we consider a modified description of CDM particles which is implied by a new fundamental theory: In this picture, the dark matter is…
We motivate Higgsino dark matter from a solution to the cosmological moduli/gravitino problem. Cosmological moduli/gravitino should be heavy enough to decay before the onset of Big Bang Nucleosynthesis, and this requirement typically forces…
A widely accepted viewpoint is to consider candidates for cosmological dark matter as neutral and weakly interacting particles, as well as to consider only light elements in the pregalactic chemical composition. It is shown that stable…