Related papers: Modified Dust and the Small Scale Crisis in CDM
The Cold Dark Matter (CDM) model, wherein the dark matter is treated as a pressureless perfect fluid, provides a good fit to galactic and cosmological data. With the advent of precision cosmology, it should be asked whether this simplest…
We perform numerical evolutions of cosmological scenarios using a standard general relativistic code in spherical symmetry. We concentrate on two different situations: initial matter distributions that are homogeneous and isotropic, and…
Modified dark matter (MDM) is a phenomenological model of dark matter, inspired by gravitational thermodynamics. For an accelerating Universe with positive cosmological constant ($\Lambda$), such phenomenological considerations lead to the…
Currently, most of the numerical simulations of structure formation use Newtonian gravity. When modelling pressureless dark matter, or `dust', this approach gives the correct results for scales much smaller than the cosmological horizon,…
A smooth unclustered dark matter component with negative presure could reconcile a flat universe with the many observations that find a density in ordinary, clustered matter well below the critical density and also explain the recent high…
Modified Dark Matter (MDM) is a phenomenological model of dark matter, inspired by gravitational thermodynamics, that naturally accounts for the universal acceleration constant observed in galactic rotation curve data; a critical…
We introduce a higher-derivative action for dark matter whose energy-momentum tensor describes an imperfect fluid with nonzero pressure, energy flux, and anisotropic stress. In the limit where the higher-derivative couplings are switched…
Modified dark matter (MDM, formerly known as MoNDian dark matter) is a phenomenological model of dark matter, inspired by quantum gravity. We review the construction of MDM by generalizing entropic gravity to de-Sitter space as is…
We explore a cosmological model in which dark matter is non-minimally coupled to gravity at the fluid level. While typically subdominant compared to Standard Model forces, such couplings may dominate dark matter dynamics. We show that this…
Emergent modified gravity is a canonical theory based on general covariance where the spacetime is not fundamental, but rather an emergent object. This feature allows for modifications of the classical theory and can be used to model new…
As one of the fundamental unknowns of our Universe, the mass of dark matter remains to be a topic of great interest. We consider the possibility of a time-variation of the dark matter mass. We study the cosmological constraints on a model…
The widely accepted dark matter hypothesis offers a seductive solution to missing mass problems (galaxies, clusters of galaxies, gravitational collapse in structure formation,...). However the physical nature of the Dark Matter itself is…
The possibility of dark matter being a dissipative component represents an option for the standard view where cold dark matter (CDM) particles behave on large scales as an ideal fluid. By including a physical mechanism to the dark matter…
Cold dark matter (CDM) models predict small-scale structure in excess of observations of the cores and abundance of dwarf galaxies. These problems might be solved, and the virtues of CDM models retained, even without postulating {\it ad…
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…
Cold Dark Matter (CDM) has become the standard modern theory of cosmological structure formation. Its predictions appear to be in good agreement with data on large scales, and it naturally accounts for many properties of galaxies. But…
Cold Dark Matter (CDM) has become the standard modern theory of cosmological structure formation. Its predictions appear to be in good agreement with data on large scales, and it naturally accounts for many properties of galaxies. But…
We report the existence of horizonless compact object solutions supported by dust in the Minimal Exponential Measure (MEMe) model, a theory which modifies the couplings between gravity and matter without introducing dynamical degrees of…
We investigate the characteristic modifications in the evolving cosmological perturbations when dark energy interacts with dust-like matter, causing the latter's background energy density fall off with time faster than usual. Focusing in…
The dark energy plus cold dark matter ($\Lambda$CDM) cosmological model has been a demonstrably successful framework for predicting and explaining the large-scale structure of Universe and its evolution with time. Yet on length scales…